Product Reviews (82)

Search term may appear only in full report available to members. Sign in or Join now for full access.

CL Answers (168)

Search term may appear only in full report available to members. Sign in or Join now for full access.

Recalls & Warnings (200)

Search term may appear only in full report available to members. Sign in or Join now for full access.

Clinical Updates (314)

Search term may appear only in full report available to members. Sign in or Join now for full access.

7/21/2013

Vitamin D May Protect Bones From Aging

Researchers recently analyzed bone samples from people who were deficient in vitamin D and found changes indicating that the bone had "aged" and was more brittle than bone from people not deficient in vitamin D. For details about this study -- including the levels of vitamin D associated with Vitamin D May Protect Bones from Aging -- Researchers recently analyzed bone samples from people who were deficient in vitamin D and found changes indicating that the bone had "aged" and was more brittle than bone from people not deficient in vitamin D. For details about this study -- including the levels of vitamin D associated with these changes, studies of other effects of vitamin D, as well as test results and comparisons for 55 vitamin D supplements, see the updated Vitamin D Supplements Review >>   
3/29/2014

Vitamin D for Weight?

A study of overweight women who were dieting and exercising found that taking vitamin D did not increase the amount of weight they lost. Those attaining the highest blood levels of vitamin D did lose more weight than other women, but this may not have been due to vitamin D. For details about the study, information about other uses of vitamin D, and our tests of vitamin D supplements, see the updated Vitamin D Supplements Review >> 
6/24/2014

Vitamin D May Help Lower Blood Pressure

A recent study in people with mild to moderate high blood pressure showed that taking a vitamin D supplement helped lower blood pressure. Subjects in the study were already taking a calcium channel blocker (nifedipine), but taking vitamin D reduced blood pressure by several additional points. For details, including the dose of vitamin D used, as well as our tests of vitamin D supplements which can provide this dose, see the updated Vitamin D Supplements Review (Including Calcium, Vitamin K, and Magnesium) >>    
8/06/2014

When Vitamin C May Curb a Cold

A recent small study among men with low to adequate levels of vitamin C showed that supplementing with vitamin C reduced the incidence of colds compared to placebo. The men taking vitamin C also reported having more energy -- although this finding was not statistically significant. Learn more about what vitamin C can and cannot do, the dose used in this study, and results of our tests of vitamin C supplements, in the update to the Vitamin C Supplements Review >>
7/18/2020

Vitamin D and Risk of Death

Increasing vitamin D blood levels was associated with a lower risk of death over time in a recently published long-term study, but only up to a certain level. Find out at what vitamin D blood level the benefit ended in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D and be aware of how much is too much vitamin D.
2/02/2019

Does Vitamin D Reduce Risk of Falls?

Vitamin D can reduce the risk of falls when given to people deficient in vitamin D. But what happens when you give high-dose vitamin D to people who are not deficient? Find out in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
6/27/2020

Signs of Too Much Vitamin D

Doctors were surprised to discover that symptoms exhibited by a 64-year old woman were due to very high levels of vitamin D from supplements. Learn about the symptoms of too much vitamin D in the Concerns and Cautions section of the Vitamin D Supplements Review. Also see our Top Picks among vitamin D supplements and learn How Much Is Too Much vitamin D.
3/04/2017

Statin Drugs and Vitamin D

If you take a statin drug to lower cholesterol, take note that recent studies show it is particularly important that you keep up your level of vitamin D. Also be aware that vitamin D supplements may not raise your vitamin D level quite as much as if you were not taking a statin. For details, see the "Statin Drugs and Vitamin D" section of the Vitamin D Supplements Review (which includes our tests of products) >>
12/03/2014

Vitamin D for COPD

A study of people with chronic obstructive pulmonary disease (COPD) found that taking vitamin D significantly reduced the risk of moderate to severe exacerbation, but only among people who began the study deficient in vitamin D. Get the details and information about other uses of vitamin D, along with our quality ratings of vitamin D supplements, in the Vitamin D Supplements Review >> 
7/24/2018

Vitamin D and Leg Muscle Strength

Giving a moderate amount of vitamin D to women deficient in vitamin D was shown to improve leg muscle strength. A much higher dose did not. Get the details, including dosage, and learn about vitamin D for strength and balance in the Muscle, Balance, and Falls section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
12/17/2019

What Happens With Too Much Vitamin D

A 50-year-old woman learned the hard way about the risks of taking far too much vitamin D. If you take a very high dose of vitamin D, be aware of the symptoms of vitamin D toxicity, as explained in the Concerns and Cautions section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
2/08/2020

Vitamin D for Hives

If you suffer from chronic hives (or chronic urticaria) and are deficient in vitamin D, taking vitamin D may be helpful, according to a new study. (Vitamin D may also be helpful for other skin conditions such as eczema and psoriasis.) Get the details in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
6/30/2013

Vitamin D & Depression

Women with depression and type 2 diabetes were given high-dose vitamin D for several weeks in a small, pilot study. By the end of the study, vitamin D levels in the blood had risen considerably and mood was significantly improved, as was blood pressure. Although just a pilot study, this is not the first study to suggest that vitamin D may help with depression. For more details, as well as test results and comparisons for 55 vitamin D supplements, see the updated Vitamin D Supplements Review >>
8/02/2012

Is Vitamin D2 or D3 Better?

Over the years, studies have shown vitamin D3 to be either equal to or better than vitamin D2 for raising vitamin D blood levels. A new study further tips the scales. Get the details, as well as our tests of vitamin D supplements, in the updated Vitamin D Supplements ReviewMore >>
7/22/2012

Vitamin D Prevents Hip Fracture

We recently reported that a U.S. Task Force found it unclear if vitamin D prevented hip fracture, but a more recent report found otherwise. The new report suggests a specific minimum blood level of vitamin D to help prevent fractures, the dosage found most effective, and the frequency at which vitamin D should be taken. Get the details in the recent update to the Vitamin D Supplements Review, which includes our tests of vitamin D supplements.  More >>
7/01/2012

Vitamin D Tests Unreliable

A preliminary report suggests that many vitamin D blood tests are incorrect, often yielding low results. This can lead to the diagnosis of vitamin D deficiency when it does not exist. Certain people may be more prone to a false low reading due to their source of vitamin D. Learn more in the update to the Vitamin D Supplements Review entitled Vitamin D Tests -- Not Always Reliable >>
6/17/2012

Don't Take Vitamin D?

Recommendations were published this week by an expert panel against the use of certain combinations of vitamin D and calcium in postmenopausal women to prevent fractures -- as the risks outweighed the benefits. However, this does not mean you shouldn’t take vitamin D. In fact the experts recommended that people at increased risk for falls should take vitamin D.  

Find out exactly what was recommended! Read the update to the Vitamin D Review. You’ll get a more complete picture of what vitamin D supplements can and can’t do, the latest information on what levels of vitamin D in your body seem optimal for overall health, and our test findings for vitamin D supplements. More >>
1/13/2013

Vitamin D and Knee Arthritis?

Can taking vitamin D reduce the pain and progression of osteoarthritis of the knee? A new study found no benefit for people who already had sufficient levels of vitamin D. In fact, these people needed more anti-inflammatory medication during the study than those given placebo. However, as seen in many other studies of vitamin D, people who entered the study deficient in vitamin D appeared to benefit from being given vitamin D, experiencing reduced pain. For more details, see the update in the Vitamin D Supplements Review, which includes our tests of vitamin D supplements. If you suffer from osteoarthritis of the knee or other joints, also read about glucosamine and chondroitin, as supplements with these ingredients may help. We have tested many of these products.
11/29/2011

More Vitamin D for Obese Adolescents

Vitamin D is fat soluble, so obese people who are deficient in it need more than other people to increase their vitamin D levels. A recent study in obese adolescents showed just how much more they need. It also determined that a relatively high dose of vitamin D was safe in these adolescents. For details, including the dosage used, see the update to the Vitamin D Supplements Review, which includes ConsumerLab.com's quality ratings and comparisons of vitamin D supplements.
1/17/2015

Vitamin D and Colorectal Cancer

Higher blood levels of vitamin D are associated with a reduced risk of colon cancer, and a new study shows this association to be strongest with a particular subtype of colon cancer. The risk of this cancer in those with higher vitamin D levels is only 10% of that in those with low levels. For details about this and the uses of vitamin D, as well as our ratings of vitamin D supplements, see the Vitamin D Supplements Review >>   
8/02/2015

Vitamin D and Inflammation

A new study of elderly people given vitamin D showed little effect on markers of inflammation in the body. Correcting very low levels of vitamin D may be helpful, but further raising vitamin levels does not seem necessary for proper immune function. In fact, there may be some downside. For details about this and other uses for vitamin D (and our product test results), see the Vitamin D Supplements Review >>
11/08/2015

Too Much Vitamin D Can Increase Colds

A recent study in people with asthma found that giving high-dose vitamin D increased the risk of developing a cold among those who achieved higher levels of vitamin D or were African-American. Nearly half of those in the study were not vitamin D deficient to start. In contrast, studies have found that giving moderate doses of vitamin D to people who are vitamin D deficient decreases the risk of colds. The point, in our opinion: Maintain an adequate, but not excessive, level of vitamin D. For details (including dosage, levels, and our tests of products) see the Vitamin D Supplements Review >>
4/06/2014

Reduced Risk of Death with Vitamin D

A recent review of clinical studies involving vitamin D concluded that supplementation with vitamin D-3 significantly reduced overall mortality among older individuals by 11%, while vitamin D-2 had no overall effect. The review did not define exactly when or how much vitamin D is most effective, but you can find sensible guidelines in the Summary section of the Vitamin D Supplements Review >> 
8/08/2014

Up To a Point, Alzheimer's Risk Falls with Vitamin D

A new study shows that, up to a point, the risks of developing Alzheimer’s disease and other forms of dementia fall with higher blood levels of vitamin D. However, the research also clarifies that exceeding a certain blood level of vitamin D provides no further benefit. In fact, additional research suggests that too much vitamin D can have negative effects. The message: Make sure you have a sufficient, but not excessive level of vitamin D. For details about these levels, as well as results of our tests of vitamin D supplements, see the updated Vitamin D Supplements Review >> 
1/22/2012

Vitamin D and Inflammation

A new study found that raising low levels of vitamin D appears to reduce inflammation in the body (based on measurements of C-reactive protein, or CRP, a marker of inflammation). However, once vitamin D levels reached what some people consider to be barely sufficient, CRP slowly but progressively increased, suggesting an inflammatory action of vitamin D at higher levels. The study raises the question of what is the ideal level of vitamin D in the body. 

Be sure you have the latest information! See the update to the Vitamin D Supplements Review, which includes details on this and other vitamin D studies, as well as our latest product tests.
4/01/2012

Vitamin D and the Risk of Death

In a six-year study of over 10,000 people in Kansas, the risk of death was found to be 164% higher among those with lower levels of vitamin D in their blood. These people were also more likely to suffer from hypertension, coronary artery disease, cardiomyopathy, and diabetes than those with higher levels. Only 29% of the people in the study had the higher level of vitamin D. For details, including the level of vitamin D associated with lower risk of death, ways to boost vitamin D, tests of vitamin D supplements, and more, see the Vitamin D Review >>
6/08/2017

How To Get Vitamin K From Food

Many of the benefits of vitamin K - such as proper blood clotting and calcium utilization for bone and heart health - are associated with getting adequate vitamin K from foods. The good news? Brand new research has found much higher amounts of vitamin K2 (the form associated with cardiovascular benefits) in dairy foods than previously known. However, the amounts vary tremendously depending on whether these foods are full-fat, or reduced-fat or fat-free. Get the details in the "Vitamin K from food" section of the Vitamin K Supplements Review. If you’re interested in a vitamin K supplement, see our Top Picks among brands.
5/05/2013

Lower Risk of Fibroids With Vitamin D

A study of women in Washington, D.C. showed that those with higher blood levels of vitamin D had a 32% lower risk of uterine fibroids -- the most common reason for hysterectomy. Unfortunately, most of the women had less than sufficient levels of vitamin D. Find out the levels associated with lowest risk of fibroids, learn how to improve vitamin D levels (without overdoing it), and get the results of our latest product tests in the Vitamin D Supplements Review >>
1/06/2013

Vitamin D and Pregnancy

A recent study shows that low levels of vitamin D in pregnant women are associated with a higher risk of babies born small for their gestational age. For details, see the update in the Vitamin D Supplements Review, which includes our tests of vitamin D supplements and extensive information about the use of vitamin D. More >>
1/08/2012

Vitamin D and Pancreatic Cancer

A lower risk of developing pancreatic cancer was recently associated with higher levels of vitamin D in the body. See the update to the Vitamin D Supplements Review for the vitamin D levels associated with decreased pancreatic cancer risk, as well as our ratings of vitamin D supplements.
4/30/2012

Cancer Findings with Natural Vitamin E

Clinical studies have raised doubts, and even concerns, about the relationship between vitamin E supplements and cancer. However, recent studies in animals suggest the tocopherols found in natural forms of vitamin E may help prevent cancer -- although the results are preliminary. For more about this, and our tests of vitamin E supplements, see the updated Vitamin E Supplements ReviewMore >>
10/07/2012

Does Vitamin D Prevent Colds?

A recent study found vitamin D supplementation did not reduce the number or severity of colds, but a closer look suggests that it can, depending on your vitamin D level. Get the details and our ratings of 51 vitamin D supplements in the updated Vitamin D Supplements Review >>
8/02/2012

Vitamin E and Liver Cancer

A study has shown a dramatic decrease in the risk of liver cancer among people taking vitamin E supplements or getting higher amounts of vitamin E from their diets. But don't necessarily rush out to get vitamin E. Read the details in the update to the Vitamin E Supplements ReviewMore >>
5/19/2013

Optimum Level of Vitamin D

New research shows that blood levels which are too low or too high for vitamin D are associated with increased risk of heart attack and earlier death. Find the "sweet spot" for vitamin D levels as well as test results for 55 vitamin D supplements in the updated Vitamin D Supplements Review >>
3/21/2015

Vitamin D for Blood Pressure?

Low levels of vitamin D in the blood are associated with high blood pressure. However, a recent review of many studies concludes that giving vitamin D doesn't help lower blood pressure. For more details about this and other potential uses of vitamin D, as well as our test-based reviews of products, see the Vitamin D Supplements Review >>
4/01/2015

Vitamin D for Diabetic Neuropathy

Supplementing with vitamin D can reduce pain and symptoms of diabetes-related peripheral neuropathy in people with type 2 diabetes who are vitamin D deficient, a recent study reports. More about the use of vitamin D in diabetes and many other conditions, as well as our product test results, are found in the Vitamin D Supplements Review >>
4/15/2015

Vitamin D and Statin-Related Muscle Pain

Taking high doses of vitamin D may reduce statin-related muscle pain in people with low blood levels of vitamin D, according to a new study. Get more information and our test reports on vitamin D supplements in the Vitamin D Supplements Review >>
11/21/2015

Ideal Vitamin D Levels to Reduce Cardiovascular Risk?

A study of a large group of Americans found that the risk of developing cardiovascular disease was 35% higher in people with low levels of vitamin D. Get the details, plus more about maintaining healthful blood levels of vitamin D, and our tests of products, in the Vitamin D Supplements Review >>

Be aware that there is also a risk of getting too much vitamin D >>
9/27/2014

Risk of Bone Fracture Higher With Too Much and Too Little Vitamin D

A large study in elderly men identified a range of vitamin D blood levels associated with the lowest risk of experiencing a bone fracture. Risk nearly tripled among men with higher levels of vitamin D as well as among those with very low levels. For details, including the range of vitamin D associated with lowest risk of fracture, see the update in the Vitamin D Supplements Review >>  
9/02/2015

Vitamin D Increases Strength

A recently published review of clinical studies found that supplementing with vitamin D can improve muscle strength in young, healthy men and women. This has also been found in older individuals and may relate to the fact that vitamin D receptors occur in skeletal muscle. However, this benefit may be limited to vitamin D deficient individuals. Get the details in the "Muscle, balance and falls" section of the Vitamin D Supplements Review >>
5/03/2014

Vitamin D Deficiency May Predict Advanced Prostate Cancer

According to a new study, prostate biopsies in men who are deficient in vitamin D are more likely to show a higher grade and stage of cancer than biopsies in men with higher levels of vitamin D. For more details, as well as our tests of vitamin D supplements, see the Vitamin D Supplements Review >> 
5/11/2014

Study Suggests Vitamin D Level for Blood Sugar Control

A certain minimum level of vitamin D in the blood is associated with normal control of blood sugar, according to a recently published study. The study focused on women who were overweight or obese but not diabetic. The vitamin D level is consistent with the range suggested by many other studies. For more details, as well as our tests of vitamin D supplements, see the updated Vitamin D Supplements Review >> 
1/18/2014

Vitamin D Helps Fibromyalgia

Fibromyalgia is an inflammation of the muscle and soft tissue which causes pain and fatigue. A recent study found that giving vitamin D reduced the pain associated with fibromyalgia. For details about the dose and target vitamin D blood level in the study, as well as our tests of vitamin D supplements, see the updated  Vitamin D Supplements Review >>   
8/18/2013

Vitamin D for Hypertension?

Some studies have suggested a modest reduction in high blood pressure with vitamin D supplementation. However, a recent study did not find such a benefit - although a closer look reveals why these results may not tell the full story. Get the details, plus more information about vitamin D and cardiovascular health, and test results for 55 vitamin D supplements, in the updated Vitamin D Supplements Review >>
10/23/2011

Vitamin E Risk

A study of healthy men who had taken a high-dose vitamin E supplement for several years showed a 17% increase in the risk of prostate cancer compared to men who took a placebo. See the Vitamin E Supplements Review for details, extensive information about vitamin E, and our quality ratings of vitamin E supplements.  More >>
3/16/2019

Vitamin D for Overactive Bladder?

Vitamin D supplementation may help vitamin D-deficient people who suffer from urinary urgency or frequency. Get the details in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
11/14/2018

Vitamin D May Prevent Cancer Deaths

A major 5-year study in which a cross-section of Americans were given high-dose vitamin D daily found no overall reductions in cardiovascular disease or cancer or death from these causes. However, when excluding the first two years of the study, the rate of death from cancer was 25% lower with vitamin D than with placebo – a finding consistent with other studies. See the details in the Cancer section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D.)
8/06/2019

Vitamin A and Skin Cancer

A study showed that people with higher intakes of vitamin A have a lower risk of developing squamous cell cancer of the skin. Does mean that taking a vitamin A supplement will help? Find out in the What It Does section of the Vitamin A Supplements Review, where we also discuss the risk of melanoma. (Also see our Top Picks for vitamin A supplements.)
8/13/2019

Vitamin D for Breast Cancer?

Some evidence suggests that having higher blood levels of vitamin D lowers the risk of breast cancer. Can very high-dose vitamin D slow tumor growth in women with breast cancer? See what a new study found in the Cancer section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
10/15/2019

Vitamin D & Blood Sugar Control

Maintaining moderate levels of vitamin D may aid blood sugar control, but, according to a recently published study, high-dose vitamin D supplementation may not help. For details, see the Diabetes, insulin resistance and glucose control section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
7/08/2020

Vitamin D & Osteoarthritis

Vitamin D may, in certain situations, reduce knee pain and improve function in people with knee osteoarthritis (due to worn cartilage). Vitamin D may also reduce foot pain associated with knee osteoarthritis, according to a recently published study. For details, see the Osteoarthritis section of the Vitamin D Supplements Review. Also see our Top Picks among vitamin D supplements.
6/24/2020

Does Vitamin D Harden Arteries?

Vitamin D regulates calcium levels in the body but does taking high-dose vitamin D lead to arterial calcifications (hardening of the arteries)? Find out what a 3-year study showed in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks among vitamin D supplements.
6/02/2020

Vitamin D for COVID-19 Patients

A study evaluated the effects of giving vitamin D, magnesium, and vitamin B12 to COVID-19 patients. See the results in the COVID-19 section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
7/28/2020

How Much Vitamin D from Sunshine?

Does exposure to midday sun increase already sufficient vitamin D blood levels? Get the surprising answer from a new study in the Getting vitamin D from sunlight section of the Vitamin D Supplements Review. Also see our Top Picks among vitamin D supplements.
1/14/2020

Vitamin D & Bone Density

Does taking vitamin D improve bone mineral density in older men and women who are not deficient in vitamin D? See what a major study found in the Bones and fractures section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
1/31/2020

Not Enough Vitamin C

Vitamin C deficiency is known to cause scurvy, characterized by bleeding gums and other connective tissue problems. But vitamin C deficiency was recently reported to cause a very different array of symptoms in several people. Learn more in the What It Does section of the Vitamin C Supplements Review. Also see our Top Picks for vitamin C.
8/08/2020

Vitamin D and Vertigo

A common form of vertigo has been linked to vitamin D deficiency, but can taking a vitamin D supplement help prevent episodes of vertigo? Find out what a recent study showed in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
12/15/2018

Magnesium for Optimal Vitamin D Level

Magnesium intake significantly affects levels of active vitamin D in the blood, according to a new study. This helps keep vitamin D in an optimal range and is another reason to get sufficient magnesium – which many people don't. For details, see the new information in the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D and magnesium supplements).
12/25/2018

Vitamin D for Muscle

Vitamin D increased muscle mass in older men and women with low levels of vitamin D in a recent study. Get the details in the Muscle, balance and falls section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D.)
4/09/2019

Vitamin D & Kidney Failure

Although rare, excess intake of vitamin D can lead to kidney failure. This recently happened to a man taking a higher dose of vitamin D than he thought. Learn more in the Concerns and Cautions section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
5/15/2019

Vitamin D and Sunscreen

Is it possible to protect your skin from sunburn but still produce vitamin D? See what a recent study found in the Getting vitamin D from sunlight section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
8/07/2018

Vitamin D and Blood Sugar Control

A recent study adds to the growing evidence that obtaining and maintaining adequate vitamin D levels can help with blood sugar control. For details about this and studies regarding vitamin D and diabetes, see the Diabetes, insulin resistance and glucose control section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D supplements.)
4/01/2018

Type 2 Diabetes and Vitamin D

Maintaining an adequate level of vitamin D is associated with a lower risk of type 2 diabetes. But does giving vitamin D to people with existing type 2 diabetes help them with glucose control? Find out what research is showing in the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
6/23/2018

Vitamin D for Strength?

Muscles contain vitamin D receptors, but does giving high-dose vitamin D to women deficient in vitamin D improve their muscle strength? Get the answer in the recent update to the Muscle, balance and falls section of the Vitamin D Supplements Review.
9/22/2018

Vitamin C and Prostate Cancer

Does taking vitamin C reduce the chance of developing prostate cancer? Find out what studies are showing, including one reported this month, in the What It Does section of the Vitamin C Supplements Review. (Also learn about vitamin C and cataracts and see our Top Picks for vitamin C.)
11/27/2018

Can Vitamin D Boost Cognition?

Middle-aged people with low levels of vitamin D were given high-dose vitamin D for four months. Find out if this boosted their cognitive performance in the Alzheimer's disease, dementia, memory and cognitive decline section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D.)
2/18/2020

Vitamin K for Bone Density?

Vitamin K (as MK-7) was given daily for one year to older men and women to see if it would improve bone mineral density. Some also received vitamin D and calcium. Find out if it helped, as well as the results of related studies, in the What It Does section of the Vitamin K Supplements Review. Also see our Top Picks among vitamin K supplements.
2/29/2020

How Much Sun for Vitamin D?

Is sun exposure to the hands, arms, and legs enough to boost or maintain adequate vitamin D levels? See what a recent study showed in the Getting Vitamin D from Sunlight section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
12/14/2019

High-Dose Vitamin D for the Critically Ill?

Critically ill patients with vitamin D deficiency were given an extremely high dose of vitamin D to see if it would reduce deaths. Find out if it helped in the How Much Do You Need and How Much is Too Much? section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
9/24/2019

Vitamin D Sprays

Are oral vitamin D sprays better than vitamin D capsules? Find out what studies are showing in the Oral Sprays section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
7/27/2019

Vitamin D for Depression?

Low blood levels of vitamin D are associated with a higher risk of depression. But does taking vitamin D reduce this risk or improve mood in depressed people? Find out what recent studies have shown in the What It Does: Depression section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D among products.
3/25/2015

Vitamin D and Reducing Injuries From Falls

Although vitamin D may be able to reduce the risk of falls in women deficient in vitamin D, a new study shows that, among women with sufficient vitamin D, it does not help and may have a negative effect. At the same time, the study showed that an exercise regime cut the rate of injuries from falls by half. Get more details in the Vitamin D Supplements Review >>
9/27/2014

Vitamin D for Asthma

A pilot study in older people with asthma found that daily supplementation with vitamin D improved symptoms among those with uncontrolled asthma. These people were also most likely to have had low blood levels of vitamin D to start. Get the details, including the dose used, and more information about the role of vitamin D in asthma, in the updated Vitamin D Supplements Review >> 
10/24/2017

Vitamin D Toxicity

Getting too much vitamin D is associated with negative effects. With continued use of enormous doses of vitamin D, toxic effects can occur, as has been reported with the use of a protein supplement containing vitamin D. See the details in the "Concerns and Cautions" section of the Vitamin D Supplements Review >>
8/20/2016

Vitamin D, Blood Sugar & Insulin Resistance

Vitamin D, Blood Sugar & Insulin Resistance --A moderate, daily dose of vitamin D had positive effects on blood glucose and insulin sensitivity in healthy men and women who largely were deficient in vitamin D, according to a new study. Get the details in the Vitamin D Supplements Review >>
12/02/2017

Autism Risk With Low Vitamin D

Babies born with very low blood levels of vitamin D are more likely to be autistic, according to a new study. This is consistent with a study published last year showing a higher rate of autistic children in mothers with very low vitamin D blood levels during pregnancy. Get the details in the "What It Does" section of the Vitamin D Supplements Review >> (Also see our Top Picks among vitamin D supplements.)
3/11/2017

Can High-Dose Vitamin D Backfire?

A recent study found that taking very high doses of vitamin D increases the production of an enzyme which inactivates vitamin D in the body -- which may help to explain why taking very high-dose vitamin D has been linked with adverse effects such as muscle weakness and increased risk of fractures and falls in previous studies. For details, see the "How Much Do You Need?" section of the Vitamin D Supplements Review (which includes our tests of products) >>
4/28/2017

Vitamin D for Muscle and Balance?

Why did a recent study show that both high and low-dose vitamin D didn’t improve muscle strength or balance in women despite the fact that other studies have shown vitamin D to help? The likely answer has to do with the vitamin D status (i.e., blood levels) of the people chosen to participate in these studies. To find out what you should do to improve your balance and reduce your chance of falling, see the "Muscle, Balance and Falls" section of the Vitamin D Supplements Review >>
5/20/2015

Vitamin D Strengthens Muscle

In a recent study, a modest daily dose of vitamin D led to impressive gains in leg strength in women who were deficient in the vitamin. Details about this study (including dosage) and other studies of vitamin D, along with our reviews of products, are found in the Vitamin D Supplements Review >>
6/17/2015

High-Dose Vitamin D Increases Upper Respiratory Infections

A study among older people found that taking a high dose of vitamin D every 2 months increased the risk of upper respiratory infection by 48% compared to taking low-dose vitamin D daily. Infections lasted two days longer for those taking the high dose versus the low dose. For details, including dosage, as well as our test reports on vitamin D supplements, see the Vitamin D Supplements Review >>
7/12/2014

Vitamin D & Calcium for Diabetes Due to Pregnancy

A new study found supplementation with a combination of vitamin D and calcium improved fasting blood sugar levels, serum insulin levels, and insulin sensitivity in women with gestational (pregnancy-related) diabetes. For more details, including dosage, as well as our tests and comparisons of vitamin D and calcium supplements, see the update to the Vitamin D Supplements Review (Including Calcium, Vitamin K, Magnesium) >>   
12/08/2016

Vitamin D Keeping You Up?

A study of women given daily doses of vitamin D found that those who achieved the highest blood levels of vitamin D experienced a deterioration in the quality of their sleep. This is consistent with an earlier study showing decreased production of melatonin with high-dose vitamin D. For details, see the "Concerns and Cautions" section of the Vitamin D Supplements Review >>
6/22/2011

Does Taking Vitamin D Reduce the Risk of Heart Disease?

Earlier research has suggested an association between higher vitamin D levels in the blood and reduced risk of heart attack. But blood levels are affected by both sun exposure as well as intake of vitamin D. A new study shows that men with higher vitamin D intakes from foods and supplements have a 14% reduction in their risk of cardiovascular disease and stroke. However, the study found no reduction among women. The amount of vitamin D intake shown to be beneficial and possible reasons why a benefit was not found in women are provided in the updated "What It Does" section of our Product Review of Vitamin D SupplementsMore >>
12/02/2012

Vitamin D and Diabetes Risk

A new study shows a strong association between lower levels of vitamin D in the blood and a higher risk of developing type 1 diabetes (i.e., requiring insulin). The risk of diabetes was more than 3.5 times as great among people with low levels of vitamin D compared to those with higher levels -- although no additional benefit was found for people with the highest levels of vitamin D. Find out more -- including the specific level associated with the lowest risk of type 1 diabetes -- in the updated Vitamin D Supplements Review, which includes our test results for 51 vitamin D supplements. More >>
4/28/2020

A Role for Vitamin K in COVID-19?

A new study showed a link between vitamin K and the development of COVID-19. Learn what this means in the What It Does section of our Vitamin K Supplements Review. Also see our Top Pick among vitamin K supplements.
8/02/2020

Magnesium Helps Vitamin D

Magnesium can boost blood levels of an important form of vitamin D, according to a recent study. For details on how much magnesium to take and when, see the Magnesium affects vitamin D levels section of the Vitamin D Supplements Review. To find a good magnesium supplement, see our Top Picks for magnesium.
8/25/2020

B-12 Supplements vs. Injections

Can taking a B-12 supplement work as well as an injection to correct vitamin B-12 deficiency? See what a new study found in the B-12 section of the B Vitamin Supplements Review. Also see our Top Picks for vitamin B-12 and other B vitamin supplements.
8/26/2020

Vitamin K & Heart Health

Can taking vitamin K supplements improve vascular stiffness or lower blood pressure in people with kidney disease? Find out what a recent study showed in the What It Does section of our Vitamin K Supplements Review. Also see our Top Picks for vitamin K.
8/29/2020

Vitamin D for Asthma?

Does giving high-dose vitamin D to children with asthma reduce their need for inhaled steroids or allow them to go longer between attacks? Find out what a recent study showed in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
7/08/2020

Vitamin D and COVID Severity

Another study suggests a link between having an adequate level of vitamin D and the severity of COVID-19 in patients. For details, see the COVID-19 section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
5/05/2020

Does Too Much Vitamin D Hurt Muscle?

A study among women given moderately high doses of vitamin D found that they lost strength. Further analysis of the data suggests why. Get the details in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
8/18/2020

Vitamin D Deficiency & COVID Death Risk

A new study suggests a link between vitamin D deficiency and higher risk of death in COVID-19 patients. For details, see the COVID-19 section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
9/08/2020

Vitamin D and Risk of Death

Middle-aged men with very low blood levels of vitamin D were found to be much more likely to die over the next dozen years than men with the highest levels, according to a recent study. Learn more in the What It Does section of Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
9/08/2020

Vitamin D for Autism Spectrum Disorder?

Can vitamin D improve symptoms of autism spectrum disorder? Find out what a recent study showed in the What It Does section of Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
10/14/2017

Fatty Liver and Vitamin D

A recent study showed that it is difficult to raise vitamin D levels in some people who have non-alcoholic fatty liver disease -- a condition affecting 30% of Americans. This is concerning, as there may be benefits to raising low levels of vitamin D in such people. Learn more in the "What It Does" section of the Vitamin D Supplements Review >>
6/15/2018

Vitamin D & Colorectal Cancer Risk

What level of vitamin D is associated with the lowest risk of colorectal cancer according to a recent study? Find out in the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
12/01/2018

Vitamin D for Restless Legs?

Does high-dose vitamin D help women and men with restless legs syndrome? Find out what a recent study reported in the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D.)
8/03/2019

Vitamin D & Diabetes

Vitamin D supplementation can improve insulin sensitivity in some people at risk for type 2 diabetes according to a recent clinical study. For details about this, as well as related research, see the Diabetes, insulin resistance and glucose control section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
8/27/2019

Effect of High-Dose Vitamin D on Bones

A 3-year study among people with osteoporosis compared the effects of moderate vs. high doses of vitamin D on bone density and bone strength. The results may surprise you. Get the details in the How Much Do You Need and How Much is Too Much? section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
12/03/2019

Vitamin C and Kidney Damage

High doses of vitamin C have been reported to cause a form of kidney damage, although this is more common in people with certain pre-existing medical conditions. For details, see the Concerns and Cautions section of the Vitamin C Supplements Review. Also see our Top Picks for vitamin C supplements.
6/13/2020

Vitamin D and COVID-19 Risk

Vitamin D deficiency was associated with an increased risk of testing positive for coronavirus according to a recent study. For details see the COVID-19 section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
7/04/2020

Vitamin D & Coronavirus

Studies are linking low blood levels of vitamin D to higher risk of testing positive for the coronavirus and/or developing more severe disease. Find out what blood levels appear to be protective, as well as the results of the most recent study, in the COVID-19 section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
8/04/2020

Vitamin D and Depression

Can taking 2,000 IU of vitamin D daily lower the chance of developing depression? Find out what a major study showed in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks among vitamin D supplements.
9/04/2020

Seasonal Use of Vitamin D

The airway's ability to fight infections is reduced during the winter/spring and vitamin D might help, according to a recent study. For details, see the What It Does section of vitamin D Supplements Review. Also see our Top Picks for vitamin D.
12/13/2016

Vitamin D for Autism

A recent study among young children with autism found that high-dose vitamin D reduced autism symptoms from moderate to mild. This is a preliminary study and more research is required. For details about this study and other uses of vitamin D, as well as our tests and comparisons of products, see the "What It Does" section Vitamin D Supplements Review »
12/17/2016

Vitamin D and Autism Risk

Children whose mothers are vitamin D deficient during pregnancy are much more likely to have autistic traits by age six than those whose mothers have sufficient levels during pregnancy, according to a new study. Get the details, as well as our reviews of vitamin D supplements, in the "What It Does" section of the Vitamin D Supplements Review »
5/27/2015

Adding Vitamin D to Statin Treatment

A recent study among people taking statin medication for high cholesterol showed significant improvements in cholesterol levels when daily vitamin D was added as treatment. Improvements were greatest among those who began with lower blood levels of vitamin D. More details, along with our reviews of products similar to the one used in this study, are found in the Vitamin D Supplements Review >>
7/23/2016

Vitamin C and Breast Cancer

Higher intakes of vitamin C from foods are linked to lower risk of postmenopausal breast cancer in women, but getting vitamin C from supplements on top of that may increase the risk, says a new study. Get the details in the Vitamin C Supplements Review >>
7/12/2016

Vitamin D & Fatty Liver

Vitamin D supplementation may decrease fat accumulation in the liver in people with non-alcoholic fatty liver disease who are vitamin D deficient. Get the details in the "What It Does" section of the Vitamin D Supplements Review >>
4/17/2016

Vitamin D and Allergy

Vitamin D is known to modulate the immune system. Having sufficient levels is associated with reduced risk of allergy and asthma. A recent study showed that giving vitamin D to pregnant women and their infants resulted in fewer infants being allergic to house dust mites and needing to see a doctor for asthma. For details, see "Allergy," as well as "Asthma," in the What It Does section of the Vitamin D Supplements Review >>
8/03/2016

Is Ester-C Better?

One of the forms of vitamin C in supplements is Ester-C. In addition to being non-acidic, a recent study suggests another possible benefit over regular vitamin C (ascorbic acid). Get more information about this and other forms of vitamin C in the "ConsumerTips" section of the Vitamin C Supplements Review >>
4/01/2017

Vitamin D and Cancer

Although studies have shown that sufficient vitamin D in the blood is associated with lower risk of developing and dying from cancer, a new study among women found no cancer benefit from taking vitamin D supplements. However, the study had a major weakness. For details, see the "What It Does -- Cancer" section of the Vitamin D Supplements Review >>
4/13/2019

Does Vitamin D Improve Cancer Survival?

Does giving high-dose vitamin D to people with cancer of the colon or other parts of the digestive tract improve survival rates? Find out what recent studies are showing in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
2/16/2017

Vitamin D Reduces Risk of Colds & Flu

A study released today shows that taking vitamin D in a certain way reduces the risk of cold and flu infections by up to 70%. The benefits are greatest for people very deficient in vitamin D. For details, see the "What It Does" section of the Vitamin D Supplements Review (which includes our tests of products) >>
12/17/2017

Vitamin A & Autism

Giving vitamin A to young children with autism spectrum disorders and low blood levels of vitamin A (as retinol) seemed to improve some symptoms of ASD, according to a pilot study. For details, see the "What It Does" section of the Vitamin A Supplements Review >>
1/06/2018

Vitamin D's Cardiovascular Effect

Taking vitamin D can improve aspects of cardiovascular function in certain situations, as shown in a recently published study. Get the details in the "Cardiovascular disease, blood pressure, and cholesterol" section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
1/16/2018

Link Between Vitamin D and Multiple Sclerosis?

Although some studies suggest vitamin D deficiency is a risk factor for developing multiple sclerosis, a recent review found vitamin D intake was not associated with a reduced risk. Learn more in the "What It Does" section of the Vitamin D Supplements Review >>
10/24/2017

Vitamin D for Asthma

Taking vitamin D can reduce the number of asthma exacerbations that require corticosteroid treatment, according to a recent study. Get the details in the "What It Does" section of the Vitamin D Supplements Review >> [Also see our Top Picks among vitamin D supplements in the Review.]
7/09/2019

Vitamin D for Depression?

Can supplementing with vitamin D help people who suffer from depression? Recent studies suggest it may benefit some. See the details in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
8/05/2015

More Evidence Against Too Much Vitamin D

A well-controlled study has shown that post-menopausal women do not benefit from taking vitamin D when they are not truly deficient. Get the details on appropriate dosage and use of vitamin D, as well as product test results, in the Vitamin D Supplements Review >>
9/09/2015

Vitamin C: The Exercise Replacement?

A small clinical study recently found that taking vitamin C had a positive effect on blood vessels similar to a daily walk. The study focused on overweight and obese individuals, in whom blood vessel tone is compromised. Long-term effects were not studied. Get details about the study (including dose) and other pros and cons of vitamin C in the Vitamin C Supplements Review >>
4/12/2016

Too Much Vitamin D Weakens Legs

In recent months we have reported that giving too much vitamin D to people who don’t need it increases the risk of falls. A major study now shows that it also weakens leg muscles – apparently to the surprise of the researchers. Keep in mind that giving vitamin D to people who are deficient in it can decrease the risk of falls. Get the details in the Vitamin D Supplements Review >>
4/05/2017

Don't Bother with High-Dose Vitamin D

Taking a moderate dose of vitamin D (particularly if you are deficient) can be very helpful, but a growing number of studies show a lack of benefit (and some adverse effects) with high-dose vitamin D. The latest study, released this morning, focused on cardiovascular disease. For details, see the "Cardiovascular disease" section of the Vitamin D Supplements Review >>
6/10/2017

Vitamin D & Alzheimer's Disease

Older people with insufficient levels of vitamin D had nearly triple the risk of developing Alzheimer’s disease that those with sufficient levels, according to a recent study. Those with the lowest levels also experienced a faster rate of cognitive decline. Get the details and information about optimal vitamin D levels in the "What It Does" section of the Vitamin D Supplements Review, which includes our Top Picks among supplements.
10/31/2016

Vitamin D Spray

A study found that vitamin D oral spray was no better than capsules in raising vitamin D levels in healthy men and women. However, a similar study in people with intestinal conditions that can affect absorption suggests a spray may be better. For details (as well as our ratings of products), see the ConsumerTips section of the Vitamin D Supplements Review >>
7/09/2017

Vitamin D2 or D3?

Although both the D2 and D3 forms of vitamin D can raise blood levels of vitamin D, a new study showed one to be significantly better than the other – and there are some interesting explanations for this. Learn more in the "What to Consider When Using" section of the Vitamin D Supplements Review, which includes our Top Picks.
7/26/2017

How Vitamin B6 May Backfire

Supplementing with high-dose vitamin B6 can sometimes cause the same nerve toxicity associated with deficiency of B6. New research explains why this may happen and suggests how to avoid it. For details, see the "Vitamin B6" section of the B Vitamin Supplements Review >>
11/21/2017

Vitamin D and Cardiovascular Disease

Can high doses of vitamin D improve cardiovascular function? A large, one-year study in England recently sought to answer this question. Learn what the researchers discovered in the "What It Does" section of the Vitamin D Supplements Review (which includes our Top Picks for vitamin D supplements).
7/27/2019

Vitamin D for Allergies?

If you already take an antihistamine for allergies, will adding vitamin D provide further benefit? Find out what a recent study showed in the What It Does: Allergies section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D among products.
4/06/2019

Vitamin D for Depression?

Can supplementation with vitamin D help people diagnosed with depression? Learn what the latest studies are showing in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.
6/02/2019

Vitamin D for Psoriasis?

A recent study evaluated the effects of giving high-dose vitamin D to people with plaque psoriasis. See the results in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
6/09/2019

Vitamin D for Diabetes Prevention

Does high-dose vitamin D help prevent people with pre-diabetes from progressing to type 2 diabetes? See the results of a major new study in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
10/20/2016

Vitamin D Sweet Spot

Having the right blood levels of vitamin D has many proven benefits, but too little and too much vitamin D can be problematic. A new study shows this also to be true in people with diabetes with regard to a type of nerve damage that can affect blood pressure and heart rate. For details see the "What It Does" section of the Vitamin D Supplements Review >>
12/07/2019

Vitamin D & Muscle

If you are looking to increase muscle mass, make sure you're getting adequate vitamin D. Raising deficient levels has been shown to increase muscle in seniors, and more recently, in men and women in their 40s. For details see the Muscle, balance and falls section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
2/11/2020

Vitamin C & Lungs

Supplementing with vitamin C to correct deficiency can reverse a form of lung disease, as exemplified in a recent report. For details, see the What It Does section of the Vitamin C Supplements Review. Also see our Top Picks for vitamin C.
8/09/2019

Vitamin D During Pregnancy

Does giving expectant mothers a high dose of vitamin D reduce the risk of tooth defects in their children? Find out in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
10/01/2019

Vitamin D and Risk of Cancer Death

Are you more likely to survive colorectal cancer if you have higher blood levels of vitamin D? Find out in the Cancer section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
2/25/2020

Vitamin D for Mom Affects Baby's Bones

Taking high-dose versus very-low-dose vitamin D during pregnancy led to greater bone density in offspring, according to a recent study. But, there are important caveats. Get the details in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
7/17/2018

Lower Cancer Risk With High Vitamin D?

A recent analysis suggests that breast cancer risk is lowest with vitamin D blood levels at or above 60 ng/mL -- an unusually high level. Before you try this at home, be sure to read our commentary in the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D.)
9/11/2018

High-Dose Vitamin D Risk

A new study suggests that very high-dose vitamin D may increase the risk of kidney stones. For details, see the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
10/05/2018

Vitamin D and Cognition

Does taking vitamin D help older individuals with mild cognitive impairment? Learn what a new study found in the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
12/11/2018

How Important Is Vitamin D for Bones?

Many women take vitamin D supplements to maintain bone mineral density, but does it really help? A new study provides an answer. See What It Does in the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D).
9/25/2018

Vitamin D for Eczema?

Can vitamin D help with eczema? See what a new study found in the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks among Vitamin D supplements).
10/09/2018

No Bone Benefit with Vitamin D -- Really?

You may have read that a recent analysis of 81 controlled studies concluded that "vitamin D supplementation does not prevent fractures or falls, or have meaningful benefits on bone mineral density." In general, this is true, but there are important caveats. Learn more in the What It Does section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D.)
7/07/2018

Vitamin D & Headache

Recent studies suggest a connection between vitamin D blood levels and the frequency of headaches, including migraine. Get the details in the Headache section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
7/21/2018

Cancer & High-Dose Vitamin D

Does taking high-dose vitamin D reduce the risk of cancer? Find out what a major new study found in the Cancer section of the Vitamin D Supplements Review. (Also see our Top Picks for vitamin D.)
9/04/2018

Vitamin D for Mood?

Can supplementing with vitamin D improve mood during the winter? Find out what a recent study showed in the Depression & Mood section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
9/18/2018

Vitamin D for Back Pain?

Can taking vitamin D reduce back pain? Read what a recent study found in the Back Pain section of the Vitamin D Supplements Review. (Also see our Top Picks among vitamin D supplements.)
5/07/2019

Vitamin D for Vertigo?

Vitamin D may be beneficial in preventing recurrence of a common form of vertigo known as benign paroxysmal positional vertigo (or BPPV) according to a preliminary study. For details, see the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
5/11/2019

Gummies vs. Tablets for Vitamin D

Are gummy supplements better than tablets for getting vitamin D? See the results in the What to Consider When Buying section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
8/03/2018

Vitamin C for Colds?

Taking vitamin C may modestly help with colds, according to a new study -- but there's a catch. Find out in the What It Does section of the Vitamin C Supplements Review. (Also see our Top Picks for vitamin C supplements.)
2/12/2019

Vitamin C for Blood Sugar Control

High-dose vitamin C was found to help control blood sugar levels in people with type 2 diabetes in a recent study. For details, see the What It Does section of the Vitamin C Supplements Review. Also see our latest Top Picks for vitamin C.
12/14/2017

Danger from Too Much Vitamin B6

A women who was consuming large amounts of an energy drink as well as a B-vitamin complex developed symptoms of vitamin B6 (pyridoxine) toxicity (which may not be reversible), according to a recent report. Get the details in the "B6" section of B Vitamin Supplements Review >>

CL has long warned that energy drinks and shots often contain large amounts of B6 and other B vitamins.
6/09/2013

Does Vitamin D Prevent Ear Infection?

Maintaining adequate levels of vitamin D in children appears to reduce mild ear infections, but too much vitamin D may have a downside. Find out the details in our updated Vitamin D Supplements Review >>
11/04/2012

Vitamin D and Bladder Cancer

A new study looked at vitamin D levels and the risk of developing bladder cancer. Find out which levels were best, as well as which vitamin D supplements pass our tests, in the updated Vitamin D Supplements ReviewMore >>
7/01/2012

Does Vitamin D Help Manage Weight?

If you've been reading our recent newsletters, many reports are being published about the effects of vitamin D. Here's one more: People with higher levels of vitamin D tend to put on less weight than people with lower levels. See the details in the update to the Vitamin D Supplements ReviewMore >>
4/30/2012

Vitamin C and Blood Pressure

Vitamin C supplements may modestly reduce blood pressure, particularly among people with elevated blood pressure, according to a review of the latest clinical studies. Get the details, as well as our tests of vitamin C supplements, in the updated Vitamin C Supplements ReviewMore >>
6/03/2012

Too much vitamin D may increase the risk of dying

A recent study of nearly a quarter million people found those with vitamin D levels above that considered sufficient, but not much higher, had the lowest risk of dying over the study period. People with high levels of vitamin D were more likely to have died. Some earlier research suggests the same. What does this mean for you? See our update to the Vitamin D Supplements Review for more information. More >>
3/11/2012

Vitamin D to Prevent Menstrual Pain

A new study found that taking a very high dose of Vitamin D reduced pain by 41% for two months among women who suffer from painful menstrual cramps. However, there are potential concerns with such a high dose of vitamin D. For more information, including the dose used and potential concerns, see the update to the Vitamin D Supplements ReviewMore >>
3/31/2013

Low Dose of Vitamin K Helps Bone

Using a much lower dose of vitamin K than in previous studies, a new study found that intake of a particular form of vitamin K decreased age-related decline in bone mineral content and density in certain bones in postmenopausal women. Get the details, as well as our ratings of these supplements, in the updated Vitamin K Supplements Review >>
3/18/2012

Lower Melanoma Risk with Vitamin A

A study of people ages 50 to 76 found the risk of developing melanoma (over an average of 6 years) was 40% lower among those who took a vitamin A supplement than among those who did not. The protective effect appeared strongest and most statistically significant among women, and only occurred with vitamin A from retinol and, not beta-carotene. For details, including the dose (which matters), see the updated information in the Vitamin A Supplement ReviewMore >>
9/21/2011

How to Boost Your Vitamin D!

A study of people whose vitamin D levels did not rise enough despite taking a supplement found that just changing when the supplement was taken boosted vitamin D levels by 50%. To find out how and to get more details, see the recent update to the Vitamin D ReviewMore >>
9/11/2011

Vitamin D - Depression Link

A study of postmenopausal women found the risk of depression to be 21% lower among those consuming higher amounts of vitamin D. For details, including the vitamin D source and amounts associated with decreased risk, see the update to the Vitamin D ReviewMore >>
8/02/2011

Vitamin D and Diabetes Risk

A recent report showed that the risk of developing type 2 diabetes increases when vitamin D intake is low. The increased risk of diabetes is even more dramatic when vitamin D in the blood is below adequate levels. Get the details in the update to the Vitamin D Supplements Review >>.
9/16/2012

Vitamin D & Alzheimer's

A seven-year study of women over age 75 found those with higher intakes of vitamin D from their diets were 77% less likely to develop Alzheimer's disease. The amount of vitamin D intake associated with this large benefit was actually fairly modest. Get the details in the updated Vitamin D Supplements Review, which includes our product tests and quality ratings. More >>
9/16/2012

Vitamin D Speeds Recovery from Tuberculosis

A study in London found that adding vitamin D to standard antibiotic treatment for tuberculosis significantly reduced inflammation and speeded recovery. The majority of these patients, however, had been extremely deficient in vitamin D. Get the details in the updated Vitamin D Supplements ReviewMore >>
8/19/2012

Low Vitamin D Levels and Obesity -- A Dangerous Combination

A new study links low blood levels of vitamin D in obese individuals to a greatly increased risk of insulin resistance (a condition linked to type 2 diabetes). The results add to the growing list of reasons to make sure you maintain a sufficient level of vitamin D. Get the details in the latest update to ConsumerLab.com’s Vitamin D Supplements ReviewMore >>
2/27/2011

Vitamin D and Allergy?

Recent analyses of data from thousands of individuals across the U.S. show an association between serum vitamin D levels and certain allergies. The association was found in children and adolescents for 11 different allergens, but no association was found in older individuals. See the Vitamin D Product Review for the types of allergies and level of vitamin D at which risk was reduced. More >>
2/02/2011

Calcium and Vitamin D for Girls

In a recently published study, girls ages 9 to 13 were given, twice a day, a supplement with calcium and vitamin D. After 6 months, significant increases were found in bone density and strength compared to girls who received placebo. Get the amounts and types of calcium and vitamin D taken, as well as more information, in the Review of Calcium Supplements or the Review of Vitamin D Supplements.
9/29/2013

When Vitamin D Doesn't Help

A recent study in postmenopausal women in New York showed that taking a vitamin D supplement did not reduce bone loss (based on measurements of markers of bone turnover). However, calcium supplementation did appear to help. Why? It all has to do with how much vitamin D and calcium the women were already getting without the supplements. You can find out the amounts and get more details in the update to the Vitamin D Supplements Review >>
10/06/2013

Vitamin D for Adolescents

A study found that vitamin D supplementation increased bone density in the hips of adolescent girls, but not of boys. Interestingly, a high dose appeared to have less effect than a low dose. For details, including dosage and our tests of vitamin D supplements, see the updated Vitamin D Supplements Review>>
11/28/2013

Lower Vitamin D in Blacks May Be Sufficient

The traditional method of assessing vitamin D levels may not be appropriate for most black people, according to a new study. Due to a genetic variant, this approach classifies many black individuals as "deficient" in vitamin D although their levels may be adequate. For details see the update to the  Vitamin D Supplements Review >> 
2/07/2014

Vitamins C & E Blunt Exercise Effect

A recent study found that giving high-dose vitamin C or vitamin E to people involved in intensive exercise training blunted cellular changes thought to be important for improving muscular endurance. These and similar results recently reported with resveratrol raise concerns about high-dose antioxidant supplementation during exercise training. For details, see the updates to the "Concerns and Cautions" sections of the Vitamin C Supplements Review >>  and the Vitamin E Supplements Review >> 
3/08/2014

Vitamin D and Breast Cancer Survival

A new analyses of clinical studies found that women with the highest blood levels of vitamin D had a much higher rate of survival from breast cancer than women with the lowest levels. Details on what may be the most beneficial levels, as well as our test results for vitamin D supplements, are found in the updated Vitamin D Supplements Review >>  
9/16/2015

Adequate Vitamin D May Lower Risk of Alzheimer's

A study showed that men and women with adequate levels of vitamin D in their blood were less likely to experience declines in cognitive functioning associated with Alzheimer’s dementia than those with lower levels. More about the study, including the vitamin D level considered adequate, as well as our reviews of supplements, is found in the Vitamin D Supplements Review >>
10/03/2015

Vitamin D Reduces Risk of Falls

A study found that giving a modest daily dose of vitamin D significantly reduced the rate of falls in women who were prone to falls and were deficient in vitamin D. Get details about this and other studies, as well as results of our product tests, in the Vitamin D Supplements Review >>
8/19/2015

Vitamin D Reduces Risk of Falls

A recent study found that in older adults, many of whom had insufficient levels of vitamin D and a history of falls, vitamin D supplementation reduced the number of reported falls by almost half. Get the details, including dosage, and our tests of popular products, in the Vitamin D Supplements Review »
1/23/2016

Vitamin D Reduces PMS Symptoms

A recent study found that taking vitamin D significantly improved symptoms of premenstrual syndrome (PMS) in young women who were deficient in vitamin D. Get the details in the Vitamin D Supplements Review >>
2/06/2016

Football & Vitamin D

The outcome of today's Super Bowl 50 may be influenced by players' levels of vitamin D. Several studies show that having the right amount of vitamin D in the body reduces the risk of falls in the elderly, but research also shows benefits for younger adults – including fewer injuries among NFL football players. Get the details in the Vitamin D Supplements Review and enjoy the game!
3/05/2016

Vitamin D and Prostate Cancer

A recent study looked at the association between vitamin D blood levels and the risk of advanced prostate cancer. Based on the findings from this and related studies, there seems to be a reasonable approach with vitamin D to potentially lower prostate cancer risk. Get the details (as well as our tests of products) in the Vitamin D Supplements Review >>
3/08/2016

Knee Arthritis & Vitamin D

People with knee osteoarthritis (worn joints) and generally low vitamin D levels given vitamin D for 2 years showed greater improvement in some, but not all, symptoms compared to those given a placebo. Get the details (as well as our product test results) in the Vitamin D Supplements Review >>
6/04/2016

Osteoarthritis and Vitamin D

A large, long-term study among older people with knee osteoarthritis found no benefit from taking vitamin D. More details about this -- and about vitamin D for many other conditions -- are found in the "What It Does" section in our Vitamin D Supplements Review >>
4/27/2019

Vitamin D & Incontinence

Does giving high-dose vitamin D help women who have urinary incontinence? See what a recent study found in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
8/20/2014

Lower Risk of Surgical Complications with Sufficient Vitamin D

A recent study found that higher blood levels of vitamin D were associated with lower risk of developing serious post-operative complications, including death. As in other studies, the apparent benefit of higher levels of vitamin D increased only up to a point. Get the details in the update to the Vitamin D Supplements Review >> 
3/07/2015

Vitamin D Helps in Pregnancy

A new study showed that giving vitamin D to women with low levels of vitamin D resulted in a dramatic reduction in pre-term labor, pre-eclampsia, and gestational diabetes compared to untreated women. For details, see the Vitamin D Supplements Review >>
6/13/2014

Vitamin D and Rheumatoid Arthritis

A recent study shows that people with rheumatoid arthritis tend to have significantly lower levels of vitamin D in their blood than healthy individuals of the same age, gender and body weight. More details, including the vitamin D levels in these groups, is found in the update to the Vitamin D Supplements Review >>   
11/17/2013

Latest Supplement Recommendations

New draft recommendations on vitamin and mineral supplement use were published this week by the U.S. Preventive Services Task Force. The recommendations apply only to healthy adults without nutritional deficiencies. They focus only on the use of supplements for the prevention of cardiovascular disease and cancer at doses not exceeding tolerable upper intake levels. The recommendations are based on existing science and are generally consistent with information already presented in ConsumerLab.com’s Product Reviews.  We have summarized the recommendations below, with links to more information in ConsumerLab.com’s reports:

- Beta-Carotene and Vitamin E:  Supplementation with either does not provide a benefit. Vitamin E does not pose a risk of harm, but beta-carotene increases the risk of lung cancer in people at risk for lung cancer.

- Other Single Vitamins, Minerals, Pairs, and Multivitamins: There is inadequate evidence regarding a benefit or a risk of harm.

The task force stressed that at excessive doses (above tolerable upper intake levels) there is evidence of harm with supplementation, such as with vitamin A and vitamin D
1/04/2014

Vitamin E Helps Alzheimer's Patients

A new study suggests that high-dose vitamin E can help people with Alzheimer's disease retain their ability to perform activities of daily living (such as dressing) for several months longer than those given placebo, reducing caregiver time. A similar dose of vitamin E has been shown in other studies to slow the progression of the disease in some people and to reduce the rate of conversion to Alzheimer's among people with mild cognitive impairment. For details -- including the dose and form of vitamin E used and our tests of supplements on the market which can provide this dose -- see the update to the Vitamin E Supplements Review >>
10/28/2012

Large Study Suggests Best Vitamin D Level

What's the best level of vitamin D in your body for overall health? One way to answer this question is to compare mortality rates (deaths per year) associated different levels of vitamin D. A new study did just this, reviewing information about thousands of Americans. It concluded the best levels are between 20 and 40 ng/mL, as the risk of dying is fairly similar across this range. However, a closer look at the findings suggests an even smaller range actually associated with the lowest mortality. For the details, as well as our suggestions on how to use vitamin D, and quality ratings of products, see the Vitamin D Review.  More >>
10/21/2012

Vitamin D for Lupus

A recent small study found that vitamin D supplements helped people with lupus (systemic lupus erythematosus -- SLE), a long-term autoimmune disease. See the update to the Vitamin D Supplements Review which has details on who may benefit, dosage, and results of our product tests. More >>
12/16/2012

Higher Vitamin Level May Slow Cognitive Decline

An 8-year study of people in their 70's found that cognitive functioning (memory and other mental skills) declined faster among those with lower blood levels of vitamin B-12 compared to those with higher levels. Particularly surprising was that 40% of the people in the study fell into the lower B-12 group, many of whom had levels which would not normally define them as deficient in B-12. This and other recent studies suggest a role for vitamin B-12 in minimizing cognitive decline in older people. For details, see the updated B Vitamin Supplements Review. More >>
7/07/2013

Calcium and Vitamin D to Prevent Fractures

A large study among post-menopausal women receiving hormone therapy showed a much lower rate of hip fracture among those who received a specific calcium/vitamin D supplement compared to those who did not get the supplement. For details about the supplement, as well as test results and comparisons for 13 calcium/vitamin D supplements, see the updated Calcium Supplements Review >>
5/20/2012

B Vitamin May Lower Blood Pressure

According to a new study, approximately 10% of the population is genetically prone to high blood pressure which may respond dramatically to a low dose of riboflavin (vitamin B-2). Read the update to the B Vitamin Supplements Review for details, including the dose used and amount of blood pressure reduction achieved. More >>
3/11/2012

Vitamin D Effect on Body Fat and Cholesterol

As we have reported earlier, adequate intake of vitamin D may decrease the risk of cardiovascular disease. A new study may help explain why. A 12-week course of vitamin D given to overweight women lead to a boost in HDL ("good" cholesterol) as well as a decrease in body fat. However, total body weight did not change and there was an increase in LDL ("bad") cholesterol, although it appeared to be less plaque-forming in nature. For details, including the dose given, see the updated information in the Vitamin D Supplement ReviewMore >>
3/11/2012

Strength Improves with Vitamin D

A review of 13 studies found that vitamin D supplements may improve balance and muscle strength, but not gait, among older individuals. See the update to the Vitamin D Supplements Review for details, including dosage. More >>
5/12/2013

Vitamin D for Infants

How much is needed and how much is too much? A new study sheds light on what's appropriate for infants. Get the facts and our tests of 55 vitamin D supplements (including baby drops) in the updated Vitamin D Supplements Review >>
5/05/2013

Vitamin D & Pneumonia

A new study in men and women ages 53 to 73 found that a low vitamin D level in the blood was almost as strong a risk factor for pneumonia as smoking! Get the details, including the level with lowest risk of pneumonia, in the updated Vitamin D Supplements Review >>
10/06/2013

Vitamin D for Post-Menopausal Women

A study compared the effects of low-dose and high-dose vitamin D on bone mineral density in post-menopausal women who were also supplemented with calcium. Both dosages helped prevent loss of bone mineral density, but the higher dose was less efficient in reducing bone turnover, i.e., bone loss, contrary to what the researchers expected.  For details, including dosage, see the updated Vitamin D Supplements Review>>
5/02/2015

Too Much Vitamin D

A U.S. study showed a recent 26-fold increase in the percentage of people with excessive blood levels of vitamin D, driven by increased supplement use. Although acute toxic effects were rare, potential long-term risks exist with these high levels. See the details in Vitamin D Supplements Review >>
9/19/2014

Can Vitamin E and/or Selenium Help Prevent Cataracts?

A study in older men in the U.S. found that taking large daily doses of vitamin E and/or selenium did not significantly reduce the risk of developing cataracts. But could the dose have been too high to be helpful? Other research has shown that "less is more" when it comes to antioxidant supplementation for cataracts. For more information, see the updates to the Vitamin E Supplements Review and the Selenium Supplements Review >> 
6/27/2015

How Vitamin B-12 Causes Acne

Vitamin B-12 is a critical nutrient and many people, particularly those over 50, should supplement with B-12 to avoid deficiency. However, at doses higher than those used to prevent deficiency, B-12 may occasionally trigger acne. A new study appears to explain the B-12/acne connection. For details, see the "Cobalamin (B-12)" section of the B Vitamin Supplements Review >>
10/17/2015

Headlines Saying "Vitamin D and Calcium Don't Prevent Colon Cancer" Are Not Quite Right

A study released this week found that vitamin D and calcium supplements did not reduce the risk of developing colorectal polyps in people prone to them. A closer look at the study, however, suggests that this may not be true for everyone. Get the details in the update in the Vitamin D Supplements Review >> and the Calcium Supplements Review >>
4/20/2016

Vitamin D and Cancer

Several studies, including one published this month, show that sufficient levels of vitamin D in the body are associated with decreased risk of various forms of cancer. What’s the best level? See "Cancer" in the What It Does section of the Vitamin D Supplements Review >>
11/16/2014

Do B Vitamins Boost Memory?

This week, a study was reported in the media suggesting that taking vitamin B-12 and folic acid does not help with memory. But a closer look at this and related studies shows a benefit for some people. Get the details, plus our tests and comparisons of B-vitamin supplements, in the B Vitamin Supplements Review >> 
2/27/2014

Vitamin E, Selenium Can Increase Cancer Risk

In some men, taking high doses of vitamin E or selenium may double the risk of developing high-grade prostate cancer, according to a recent analysis. For details, including the dose, see the updates to the Vitamin E Supplements Review >> and the Selenium Supplements Review >>   
5/21/2014

Vitamin D Helpful for Asthma?

A recent study reported that giving high-dose vitamin D to asthma patients did not significantly reduce the rate of failure with conventional medications. However, a closer look at the study suggests that this conclusion is misleading and that a benefit may exist. Get the details in the update to the Vitamin D Supplements Review >> 
8/25/2013

Antioxidants: Too Much of a Good Thing?

A new, long-term study of Americans found the risk of dying over the course of the study (about 14 years) was lowest when antioxidant levels in the blood were above the lowest levels (the bottom 20% of the population). However, for people in the top 20% of blood levels for vitamins A and E, the risk of death increased compared to people with moderate levels. For selenium and beta-carotene, there was no significant difference in the death rate between moderate and high levels, although for vitamin C some additional benefit was seen at high, but not the highest, levels.
 
The results suggest that antioxidant supplements may be useful for those who are nutritionally deficient, but, as noted by the researchers, "beyond a certain threshold, higher levels do not lead to additional benefit, and may potentially be toxic." More details (including specific serum levels) are found in the linked updates to the following reviews, which include our test results and quality ratings of products:
 
 
  
  
10/30/2011

B Vitamins May Help Memory

A recently published study of individuals aged 70 years or more with mild cognitive impairment found that a daily dose of three B vitamins (folic acid, vitamin B-12, and vitamin B-6) over 2 years appeared to slow cognitive and clinical decline, particularly in those who started with elevated levels of plasma homocysteine. See the B Vitamin Product Review for details including the dosage used.  More >>
7/20/2011

Kidney Stones Linked to Calcium and Vitamin D Supplementation

A recent report showed that women taking a calcium and vitamin D supplement over a period of several years were 17% more likely to develop kidney stones than women who did not take the supplement. ConsumerLab.com reviewed this study. While the findings are correct, there seems to be no reason to give up vitamin D supplements and a small concern with calcium supplementation. Get the details in the update to the Calcium Supplements Review >>. The new information is also found in an update in the Vitamin D Supplements Review >>.
12/09/2018

Vitamin C and Kidney Damage

High doses of vitamin C can cause kidney stones and damage kidneys. People with certain diets or medical conditions may be more prone to these problems. Get the details, including those of a recent case, in the Concerns and Cautions section of the Vitamin C Supplements Review.
1/15/2019

B12 Tablet vs. Injection

Is a vitamin B12 tablet just as good as an injection for raising blood levels of B12? Find out in the Cobalamin (B12) section of the B Vitamin Supplements Review. Also see our Top Pick for vitamin B12.
7/16/2019

Is Methylfolate the Best Form of Folate?

Methylfolate has been promoted as a better form of folate (vitamin B9), particularly for people with certain common genetic variations. A clinical study recently put methylfolate to the test against folic acid and folinic acid. The results were surprising. Get the details in the Folate section of the B Vitamin Supplements Review. Also see our Top Picks among folate and other B vitamin supplements.
7/16/2019

Do Vitamin Patches Work?

We've added important new information to our answer to the question: Do Vitamin Patches Work?
5/15/2018

Too Much Vitamin B6

Be aware that you can get too much vitamin B6 from supplements and energy drinks. This can result in nerve damage and other adverse effects, as has been recently reported. For details, see the B6 section of the B Vitamin Supplements Review.
9/01/2020

Folate & Memory

Older people with high blood levels of folate are more likely to perform worse on tests of memory and cognition unless they have sufficient levels of another B vitamin, according to a recent study. Get the details in the What It Does section of our B Vitamin Supplements Review. Also see our Top Picks among B vitamin supplements.
9/21/2019

Vitamin B12 & Sleepiness

Vitamin B12 deficiency can cause a range of symptoms and, although rare, excessive daytime sleepiness is among them. Get the details about this, as well as information about other symptoms of B12 deficiency, in the B12 section of the B Vitamins Supplements Review. Also see our Top Pick for vitamin B12.
2/19/2019

Right Amount of D for Cognition

Three different doses of vitamin D were given to older women in a one-year study of cognition. Find out which dose resulted in the best performance on cognitive tests in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.
4/05/2016

Vitamin D Improves Heart Output

A recent study in people with chronic heart failure (poor heart output) found that vitamin D improved heart output. However, the study did not achieve its main objective – to increase walking distance. The dose may have been to blame. For details see the "What It Does" section of the Vitamin D Supplements Review >>
10/09/2018

Can a B Vitamin Lower High Blood Pressure?

A common mutation of the MTHFR gene is associated with an increased risk of hypertension. A recent study tested whether supplementing with a specific B vitamin could reduce blood pressure in affected individuals. Get the results in the MTHFR section of the B Vitamin Supplements Review. (Also see our Top Picks among B vitamins.)
11/16/2016

Understanding How Much Vitamin D You Need

Misunderstanding the daily requirement for vitamin D is common and can have adverse implications. To address this issue, leading experts recently published an article re-explaining the requirements. We've summarized this in the "How Much Do You Need and How Much Is Too Much?" section in the Vitamin D Supplements Review >>
11/12/2016

Vitamin D & Breast Cancer Survival

A new study making headlines this week found that women with "the highest" levels of vitamin D had better survival rates from breast cancer than women with the "lowest rates." What was left out of news stories – and may surprise you – is what these levels are. Find out in the "What It Does" section of the Vitamin D Supplements Review >>
12/05/2017

Biotin Interference With Vitamin D Test

Last week we reported that high doses of biotin (found in B complexes and hair and nail supplements) can interfere with certain blood tests. A study recently showed that biotin can also artificially inflate a test for vitamin D. Get the details in the "Biotin" section of the B Vitamin Supplements Review >>
5/20/2019

Vitamin D-Autism Study Retracted

A study that showed a benefit in giving high-dose vitamin D to children with autism spectrum disorder has been retracted due to a lack of confidence in the findings by the editors of the journal in which it appeared. For details, see the What It Does section of the Vitamin D Supplements Review.
2/11/2020

Vitamin B12 and Risk of Death

A study found higher blood levels of vitamin B12 to be associated with an increased risk of death -- suggesting caution when supplementing. For details, see the B-12 section of the B Vitamin Supplements Review. If you do need to supplement with B12, see our Top Pick among products.
2/25/2020

Cognitive Impairment From B12 Deficiency

Vitamin B12 deficiency can cause a wide range of symptoms. This includes cognitive impairment, as shown in a recent case. For details about the symptoms of B12 deficiency see the B12 section of the B Vitamin Supplements Review. Also see our Top Picks for B12 and other B vitamin supplements.
12/14/2019

B12 & the Vegetarian

Vegetarians and vegans are susceptible to vitamin B12 deficiency, which can be manifest by a range of health issues, including low blood pressure, as recently reported in an otherwise healthy young man. Learn more in the B12 section of the B Vitamin Supplements Review. Also see our Top Pick for vitamin B12.
8/26/2015

Do We Need More Vitamin E?

A study recently suggested that many Americans don’t get optimal intake of vitamin E from their diets. A closer look at this study, however, indicates that most people in the U.S. shouldn't worry. For details see the ConsumerTips section of the Vitamin E Supplements Review >>
6/10/2017

Hip Fracture Risk With Too Much B-6

A new study found that older men and women who took a high daily dose of vitamin B-6 had a 42% increased risk of hip fracture. Get the details in the "Vitamin B-6" section of the B Vitamin Supplements Review. Also, be aware that many supplements on the market contain the amount of B-6 used in this study, or more, in a daily serving! For help choosing a B-Complex or B-6 supplement that suits your needs without providing too much B-6, see our Top Picks among B vitamin supplements.
3/17/2018

High-Dose Vitamin D & Cholesterol

Giving high-dose vitamin D to people who are not deficient in it may backfire and increase cholesterol levels, as seen in a recent study. Get the details in the Concerns and Cautions section of the Vitamin D Supplements Review. (Also see our Top Picks among products).
3/06/2017

Better Executive Functioning with Vitamin D

Getting adequate vitamin D appears to help with executive functioning and attention in adolescents, according to a new study – similar to what has been preliminarily shown in men. For details, see the "What It Does" section of the Vitamin D Supplements Review (which includes our tests of products) >>
3/25/2017

Right Dose of Vitamin D to Reduce Falls

As we've reported in the past, vitamin D can reduce falls in older people, but too much can increase falls. A new study helps nail down the ideal dose and blood level to reduce falls. For details, see the "What It Does" section of the Vitamin D Supplements Review >>
8/02/2016

Vitamin D for Asthma

Short term supplementation with vitamin D improved symptoms of asthma in children, according to a new study. Get the details in the "What It Does" section in our Vitamin D Supplements Review >>
9/20/2015

Adequate Vitamin D Reduces Frequent Respiratory Infections

A study in people with frequent respiratory infections found that taking vitamin D for one year resulted in fewer infections than taking placebo. In contrast, a similar study did not find a benefit. Why the difference? Find out in the Vitamin D Supplements Review >>
5/11/2017

Early Menopause & Vitamin D

Women who get more vitamin D from their diets have a lower risk of early menopause, according to a recent study. However, supplements don't seem to help. Get the details in the "What It Does" section of the Vitamin D Supplements Review >>
9/07/2016

Vitamin D & Asthma

A daily, moderate dose of vitamin D reduces hospitalizations and use of steroid medication in people with mild to moderate asthma, according to a new study. Get the details in the "What It Does" section of the Vitamin D Supplements Review >>
9/14/2016

Raising Vitamin D Levels May Reduce Risk Factor For Breast Cancer

A study among postmenopausal women showed that raising vitamin D blood levels helps reduces blood estrogens, which are a known risk factor for breast cancer. And there’s something that reduces estrogen levels even more! For more details, see the "What It Does - Cancer" section of the Vitamin D Supplements Review >>
2/19/2016

Vitamin D Needed For Nursed Infants

A recent study found that the longer a child is nursed, the higher the risk of being deficient in vitamin D. See the details and recommendations in the Vitamin D Supplements Review >>
3/15/2016

Vitamin D and MS

A study found that children born to women significantly deficient in vitamin D during pregnancy were much more likely to develop multiple sclerosis as adults. For details, see the "What It Does" section of the Vitamin D Supplements Review >>
1/07/2017

Headache and Vitamin D

A large study of middle-aged men found that those with low levels of vitamin D in their blood were twice as likely to have frequent headaches as men with higher levels. For details, see the "What It Does" section of the Vitamin D Supplements Review >>
1/10/2017

Potential Risk with High B-12

Among people who are malnourished, those with elevated vitamin B-12 levels in their blood were twice as likely to die when hospitalized as those with lower B-12 levels, according to a new study. The study authors suggest caution with inappropriate supplementation. For more details about the study, and vitamin B-12, see the B Vitamin Supplements Review >>
1/10/2017

High-Dose Vitamin D Reduces Respiratory Infections, But With a Risk

A study among older men and women found those who took high-dose vitamin D had fewer acute respiratory infections, but a greater number of falls. Get the details in the "What It Does" section of the Vitamin D Supplements Review >>
12/14/2013

B-12 Deficiency and Acid Inhibitors

A large, new study found the risk of vitamin B-12 deficiency to be significantly higher among people taking proton pump inhibitors (e.g., Prevacid, Prilosec) or H2-blockers (e.g., Pepcid, Zantac) than among those not taking these medications. The drugs reduce acid production in the stomach, but acid is needed to release B-12 from foods, so deficiency can occur. B-12 supplements can help because acid is not needed for their absorption. For details -- and our reviews of supplements with vitamin B-12 -- see the updated B Vitamin Supplements Review >>   

Other supplements which should or should not be used with these medications are discussed in the Proton Pump Inhibitors article, which is part of the extensive Drug Interactions section of our website (where you can look up interactions for other drugs you may be taking.) 

6/09/2013

Vitamin C: Does It Fight Colds?

A new analysis says it can help – a little. Get the bottom line, plus test results for 27 products, in the updated Vitamin C Supplements Review >>
5/27/2013

Alzheimer's Changes Slowed with B Vitamins

A combination of B vitamins was found to slow brain loss in areas of the brain associated with Alzheimer's disease. This same combination of vitamins has also been shown to slow cognitive decline. Get the details on who may (or may not) benefit, dosage, plus test results for over 35 B vitamin supplements in the updated B Vitamin Supplements Product Review >>
1/08/2012

B-12 and Folic Acid for Memory

Small but significant improvements in short and long-term memory were found to occur in older people (aged 60 to 74) given modest daily amounts of vitamin B-12 and folic acid. But don't expect immediate results. Improvements were seen only after 2 years of supplementation. See the update in the B Vitamins Review for the dosage used, as well as our ratings of supplements with vitamin B-12 and folic acid.
9/21/2013

B Vitamin Supplements for Stroke?

A review of 14 clinical studies suggests that B vitamins may help prevent stroke. However, a deep reading of the report shows the benefit to be slight, at best.  For details about the study, other uses of B vitamins (including B6, B-12, folic acid, niacin and complexes), and tests of these supplements, see the B Vitamin Supplements Review>>  
9/01/2013

Calcium During Breast Cancer Treatment

A recent analysis of clinical studies concluded that supplementation with calcium and vitamin D during breast cancer treatment does not help maintain bone mineral density, although often given for this purpose. Calcium and vitamin D may certainly play other important roles. For more details, as well as test results and comparisons for 33 calcium supplements, see the updated Calcium Supplements Review >>
5/09/2011

Does folic acid affect the risk of colon cancer?

Supplementation with higher amounts of folic acid (vitamin B-9) has been shown to increase the risk of prostate cancer, but its effect on the risk of colon cancer has been unclear. A new study found no increase in colon cancer due to folic acid supplementation. But if you supplement with folic acid, be careful. See the B Vitamin Supplements Review for more >>
11/26/2014

Take Vitamin D with a Meal Containing Fats

We've been suggesting this for years and a new study re-emphasizes the point. Get the details in the ConsumerTips section of the Vitamin D Supplements Review >> 
6/20/2014

Too Much Calcium for Some?

A new study found that supplementing with even moderate amounts of calcium may cause abnormally high calcium levels in the urine (a risk factor for kidney stones) of some postmenopausal women, even when total calcium intake doesn't exceed the recommended daily allowance. Get the details in the update to the Calcium Supplements Review (Including Vitamin D, Vitamin K, and Magnesium) >>   
3/15/2015

Folic Acid Reduces Risk of Stroke

A large study in people taking blood pressure-lowering medication found that the addition of a daily folic acid (vitamin B-9 or folate) supplement significantly reduced the chance of having a stroke. This benefit is most likely to occur among people whose blood levels of folate are low. More details, including dosage and ConsumerLab.com's test-based quality ratings of folic acid supplements, are found in the B Vitamin Supplements Review >>
5/16/2015

Niacin Reduces Skin Cancer

A recent study suggests that high-dose niacin (vitamin B-3) may reduce the risk of developing certain types of skin cancer. A closer look at the study, however, raises questions about its relevance to people in North America. Get the details, as well as more information about niacin and our product test results & comparisons, in the B Vitamin Supplements Review >> 
4/28/2020

Early Sign of Thiamin Deficiency

Thiamin (vitamin B1) deficiency can cause lasting neurologic damage and affect heart function. It can occur with poor nutrition and as a result of taking certain diuretics. A recent case highlighted an early sign of thiamin deficiency that involves the eyes. We've added this information to the Thiamin section of the B Vitamin Supplements Review. Also see our Top Pick for thiamin and B complexes that contain thiamin. You can also get thiamin from a good multivitamin.
5/18/2019

Hip Fracture Risk with B6

Another study has shown a significantly increased risk of hip fracture with high intakes of vitamin B6 from supplements. For details, see the B-6 section of the B Vitamins Review. Also see how much B6 is in popular B vitamin supplements and our Top Picks.
5/18/2019

Misdiagnosed B12 Deficiency

Vitamin B12 is needed to make the genetic material in all cells. Consequently, B12 deficiency can cause a wide range of symptoms and may be misdiagnosed as other diseases. Read about two recent cases of misdiagnosed B12 deficiency in the Cobalamin (B12) section of the B Vitamin Supplements Review. Also see our Top Picks for B12.
8/13/2019

Folic Acid and Colon Cancer

Several studies have evaluated whether folate from food and/or folic acid from supplements affect cancer risk. Find out what a recent report suggests about long-term, high-dose folic acid supplementation in the Folate section of the B Vitamin Supplements Review. Also see our Top Picks for folic acid and other B vitamin supplements.
1/20/2017

Side-Effect With B-12

Certain formulations of vitamin B-12 contain additional ingredients that can cause diarrhea and bloating in some people – particularly if taking more than one pill. An apparent case of this was reported to us this week. To help you avoid this, read the details in the "What CL Found" section of the B Vitamin Supplements Review (which includes our tests of products) >>
7/19/2014

High-Dose Niacin with Statins Not Worth It

Further evidence was published this week showing that the addition of high-dose niacin (vitamin B-3) to cholesterol-lowering treatment with statin drugs provides no worthwhile benefit and appears to increase the risk of adverse side events. For details, see the Review of B Vitamin Supplements and Energy Drinks >> 
3/29/2017

Vitamin E/Selenium & Alzheimer's

A long-term study among men in the U.S. found that giving high doses of vitamin E and/or selenium did not significantly affect their risk of developing dementia. The study was part of a larger study which found that these supplements increased the risk of prostate cancer, type 2 diabetes, hair loss, and dermatitis. For details, see the "Alzheimer's disease/dementia" section of the Selenium Supplements Review >>
3/07/2018

B12 Dosage

A study compared the effects of a high weekly dose of vitamin B12 versus a much lower dose given daily. Both worked equally well. Find out why and get more details about B12 dosing in the B-12 section of B Vitamin Supplements Review.
6/20/2017

B12 Can Cause Acne

Taking very large doses of vitamin B12 can cause outbreaks of acne -- even in older people, according to a recent report. Learn more in the "B12" section of the B Vitamin Supplements Review >>
11/04/2017

B Vitamins for Memory

Many studies suggest that adequate intake of B vitamins slows age-related declines in memory and cognition. This was recently shown again in a study in England. Find out which B vitamins help, and how much you need, in the "What It Does" section of the B Vitamin Supplements Review >> [Also see our Top Picks for B vitamin supplements in the Review.]
8/26/2017

High-Dose B Vitamins & Cataract Risk

Taking high doses of B vitamins, including B vitamin complexes, folic acid and B6, was associated with a higher risk of age-related cataracts among middle-aged men and women, according to a new study. For details, see the "ConsumerTips" section of the B Vitamin Supplements Review >>
5/24/2017

POTS and Thiamin

A small study among people who suffer from POTS (postural tachycardia syndrome) suggested that supplementing with thiamin (vitamin B-1) may help some. For details, see the Thiamin (B-1) section of the B Vitamin Supplements Review >>
6/20/2017

Warning: Biotin Can Affect Thyroid Tests

Vitamins that contain megadoses of biotin (vitamin B7) can affect thyroid tests, according to recent studies. This can lead to an incorrect diagnosis of hyperthyroidism and improper treatment. See the "Biotin" section of the B Vitamin Supplements Review >>
2/03/2017

Cognitive Decline With Too Little B6

A recent study among men and women in their 60’s found that those getting inadequate amounts of vitamin B6 in their diets had much higher rates of cognitive decline. Get the details in the "What It Does" section of the B Vitamin Supplements Review (which includes our tests of products) >>
7/20/2019

Is Niagen Safe?

Niagen (nicotinamide riboside) was recently studied for its safety and ability to raise NAD+ in the body. See the results and learn more about this form of niacin (which is also in the product Basis) in the Niacin section of the B Vitamin Supplements Review. Also see our Top Picks for niacin and other B vitamin supplements.
11/29/2019

B Vitamins for Cognition

Increasing vitamin B-12 intake by those deficient in B-12 can help slow age-related declines in memory and cognition, but the dose needs to be sufficient, as suggested by a recent study. For details see the Memory, Cognition, and Alzheimer's Disease section of the B Vitamin Supplements Review. Also see our Top Picks for B-12 and other B Vitamins.
10/24/2018

B Vitamin Cancer Risk?

Giving high-dose vitamin B12 along with a modest amount of folic acid to older people was found to significantly increase the risk of colorectal cancer. See the B12 section of the B Vitamins Review for details. (Also see our Top Picks for B12 and other B vitamins.)
3/26/2019

Vitamin C Blunts Exercise Benefits

If you are trying to build muscle with resistance exercise, go easy on vitamins C and E, according to a recent study. Get the details in the Concerns and Cautions section of the Vitamin C Supplements Review.
5/28/2019

Vitamin B12 & Depression

Deficiencies in B vitamins, such as B12, can cause depression. A recent study suggests that, in pregnant women, even low-normal B12 levels are associated with a much higher risk of depression. For details, see the Depression section of the B Vitamin Supplements Review. Also see our Top Picks for B vitamins.
2/19/2019

Kidney Stones Due to Supplement?

An unusual type of kidney stone has been reported in several people who regularly consumed large amounts of a vitamin and amino acid supplement containing a particular form of choline and vitamin C. For details, see the Concerns and Cautions section of the Choline Supplements Review.
1/08/2019

B Vitamins & Breast Cancer

A reduced risk of breast cancer was associated with supplementing with certain amounts of folic acid and vitamin B12 for women predisposed to breast cancer in a new study. See the details in the "Breast cancer" section of the B Vitamin Supplements Review.
12/23/2017

Folic Acid for Cognition

Giving folic acid to older people with relatively low levels of blood folate resulted in improved cognitive performance, according to a recent study. For details, see the "Memory, Cognition, and Alzheimer's Disease" section in the B Vitamin Supplements Review >> (Also see our Top Picks for folate and other B vitamin supplements.)
10/29/2017

Best form of B12?

It’s important for many older adults and people using medications that reduce stomach acid to take a vitamin B12 supplement. Three different forms of B12 are sold. A recent study suggests that one may be better than another. Get the details in the B12 (cobalamin) section of the B Vitamin Supplements Review >> [Also see our Top Pick for B12 supplements in the Review.]
10/12/2011

Women-Vitamin Study - Key Points

You may have heard this week about a new study which found a higher risk of death among women who used certain supplements. It’s a complicated study, but we've summarized some key findings. Bear in mind that only white women ages 55 to 69 were enrolled in the study and they were followed for 22 years.

Those taking calcium supplements had a 3.8% reduced risk of death. The calcium benefit ended, however, when taking more than 900 mg per day from supplements. It's worth noting that experts suggest many older women who take calcium supplements may not need to -- see the Calcium Supplement Review for more.

The mineral most strongly associated with an increased risk of death was iron, which showed a risk increase of 3.9% -- and the risk increased as the dose increased, particularly over 50 mg per day. However, the study grouped dosages of under 50 mg together, making it hard to determine the risk of low dosages of iron, such as those in many multivitamins. However, there is very little reason why a postmenopausal woman should be taking iron -- see the Iron Supplement Review for more.

Although not as statistically meaningful, other supplements were associated with the following increases in the risk of death during the study: multivitamins (2.4%), vitamin B6 (4.1%), folic acid (5.9%), magnesium (3.6%), zinc (3.0%), and copper (18.0%). An abstract of the study is online.

The bottom line: Don't take a supplement you don't need. If you want to know how much of each vitamin and mineral you need from your total diet and how much is too much, see our chart at www.consumerlab.com/RDAs.
5/31/2011

Niacin Concern Stops Cardiovascular Study

A clinical trial using high dose niacin (vitamin B3) was recently stopped by the National Institutes of Health due to lack of benefit and a small increase in strokes. Patients in the study had cardiovascular disease and were already taking a statin drug to keep LDL ("bad") cholesterol levels low. The addition of high dose niacin was intended to increase HDL ("good") cholesterol, reduce elevated triglycerides, and, most importantly, reduce the risk of heart attacks and stoke. For more information, including the amount and type of niacin used in the study and additional information about niacin and niacin supplements, see the B Vitamin Supplements ReviewMore >>
8/06/2020

B Vitamins and Fracture Risk

High homocysteine levels have been linked with increased fracture risk in older people. Taking B vitamins can lower homocysteine levels, but does it lower fracture risk? Find out what a recent study using folic acid and B12 showed in the What It Does section of the B Vitamin Supplements Review. Also see our Top Picks for B vitamins.
11/01/2019

Eye Risk With High-Dose Niacin

Very high doses of niacin are sometimes used to lower high cholesterol, but there are risks -- including damage to the eye, as shown in a recent case. Get the details in the Niacin section of the B Vitamin Supplements Review.
3/25/2020

Surprising Role of Potassium in COVID-19

New research out of China suggests that many patients hospitalized with COVID-19 are low in potassium. For details see the information about Potassium in our answer to the question: What are natural remedies for coronavirus (COVID-19)? Do supplements like zinc, vitamin C, or herbals work?
5/15/2020

High Blood Pressure Risk With Too Much Folic Acid During Pregnancy

While it is important to take folate during pregnancy, a new study suggests that too much folic acid from supplements increases the risk of high blood pressure in mothers. See the details in the Folic Acid section of the B Vitamin Supplements Review.

Also see our Top Pick among prenatal vitamins, which provides adequate (but not too much) folic acid, in our Multivitamin and Multiminerals Supplements Review.
6/29/2017

Choline Missing From Prenatals

The American Medical Association recently voted to recommend that all prenatal vitamins include appropriate amounts of choline. Getting adequate choline may reduce the risk of birth defects in children, but most women don’t get enough and prenatal vitamins typically provide little to none. Find out how to get adequate choline from supplements and/or foods in the Choline Supplements Review, which includes our Top Picks. Also see the "Prenatal Vitamin" section of the Multivitamin Supplements Review.
2/16/2019

Energy Drinks & Aggression

Are people who frequently consume energy drinks (like 5-hour Energy) more likely to be aggressive or have mental health problems? Learn what a new study found, and learn more about the pros and cons of energy drinks in the Energy Drinks section of the B Vitamin Supplements Review.
11/28/2017

Growing Concern with Biotin Causing False Lab Results

Biotin (a B vitamin found in B-complex and hair and nail supplements) can interfere with laboratory results resulting in the missed diagnosis or misdiagnosis of cardiovascular and hormonal conditions, such as Graves' disease (a form of hyperthyroidism). Physicians and lab personnel may be unaware of this interference. For details, see the "Biotin" section of the B Vitamins Review >>
11/20/2018

Liver Toxicity With Niacin

The death of a woman from acute liver failure highlights the risk of a particular formulation of high-dose niacin. For details, see the Niacin section of the B Vitamin Supplements Review. (Also see our Top Picks for niacin and other B vitamins.)
4/03/2018

What Niagen Does

Niagen (nicotinamide riboside) has been promoted as an anti-aging supplement. Find out what's been shown in clinical studies, including one published recently, in the Niacin section of the B Vitamin Supplements Review.
5/22/2018

Hair & Nail Supplements Can Skew Lab Tests

There are reports of high-dose biotin (common in "hair and nail" supplements) causing false readings on blood tests. Be sure to tell your doctor if you're taking high-dose biotin. Get the details in the Biotin section of the B Vitamin Supplements Review.
11/26/2017

Signs of B12 Deficiency

B12 deficiency is not uncommon, most often affecting older people. Symptoms include anemia, fatigue, tingling in the arms and legs and loss of balance -- but a recent case report highlights a lesser-known sign of B12 deficiency. Find out more, plus how much B12 you should get in the "B12" section of the B Vitamins Review >> (Also see our Top Picks for vitamin B12 and other B vitamins.)
2/29/2020

Biotin May Skew Many Blood Tests

If you take a high-dose biotin supplement, be aware of the growing list of blood tests with which it may interfere. See the latest information in the Biotin section of the B Vitamin Supplements Review.
6/19/2019

NAD+ and Cancer?

Supplements that raise NAD+ levels in the body have been promoted for anti-aging effects. But there is a theoretical risk that they could stimulate cancerous cells, and a CL member reported this week that a supplement containing such an ingredient, nicotinamide riboside, appeared to increase his PSA level. Learn more in the Niacin section of the B Vitamin Supplements Review.
8/29/2017

High-Dose B Vitamins & Lung Cancer Risk

A recent study found that taking high doses of vitamins B6 and B12 was associated with an increased risk of lung cancer among men, particulary among those who smoke. For details, see the "ConsumerTips" section of the B Vitamin Supplements Review >>
11/11/2019

Platelet Concern With High-dose Niacin

Long-term use of high-dose niacin may lower platelet counts. Learn more in the Niacin section of the B Vitamin Supplements Review.
9/19/2017

Niacinamide for Alzheimer's Disease?

Niacinamide (a form of niacin) has been promoted as a way to protect against memory loss associated with Alzheimer's disease – a claim based on studies in mice. A recent study put this to the test in people. See the results in the "Niacin" section of the B Vitamin Supplements Review >>
3/02/2018

Calcium and Colon Polyp Risk

A large study evaluated the effects of taking calcium and/or vitamin D on the risk of developing precancerous colorectal polyps in people with previous polyps. While there was no effect during the study, a follow up study is now showing much higher rates of polyps among those who had taken certain supplements. Get the details in the What It Does section of the Calcium Supplements Review.
1/13/2018

B12 for Cognition

Numerous studies show that getting adequate intake of B vitamins, such as B12, and, perhaps, omega-3 fatty acids from fish, may slow age-related declines in memory and cognition. But not everyone should expect a benefit, as shown in a recent study. For details, see the Memory, Cognition, and Alzheimer's Disease section of the B Vitamin Supplements Review. (Also see our Top Picks among products.)
12/26/2017

Folic Acid & Risk of Autism

Supplementing with adequate (and not excessive) folic acid around the time of conception is associated with a lower risk of autism in offspring, and a recent study suggests this may be particularly important for women who take antiepileptic medication. For details, see the "Folate" section of the B Vitamin Supplements Review >> (Also see information about getting folic acid from prenatal vitamins in the "Prenatal" section of the Multivitamin Review.)
4/08/2017

Exercise Benefit Lost With High-Dose Vitamins

Older men asked to perform resistance (strength) training for 12 weeks showed less gain in bone density if they were given high daily doses of vitamins C & E than if they were given a placebo. This is not the first time that  high-dose antioxidant supplements have been shown to reduce benefits from exercise. For details, see the "Concerns and Cautions" section of the Vitamin C Supplements Review >>
4/19/2017

Niacin & Skin Cancer

People who don't get enough niacin each day may be able to lower their risk of developing squamous cell skin cancer by getting a bit more niacin from their food or supplements suggests a recent analysis. However, this doesn't mean you should overdo it. For details, see the "Niacin" section of the B Vitamin Supplements Review. You can also find foods high in niacin using the food table in the report.
8/20/2016

Biotin Caution

Very high-doses of biotin (vitamin B-7) can cause misleading laboratory results and lead to unnecessary antithyroid treatment, according to a new report. For details, see the Biotin section of the B Vitamins Supplements Review >>
10/11/2016

Niagen Form of Niacin May Cause Flushing

Niacin is known to cause flushing (redness) and skin tingling at moderate doses. Other forms of niacin are said cause less flushing. One of these is Niagen. However, results of a recently published study suggest that it can cause flushing and "hotness" after just a single dose. More details are in the "Niacin" section of the B Vitamin Supplements Review >>
6/12/2016

B Vitamins & Autism Risk

Excessive blood levels of B-12 and/or folate in pregnant women were found to be associated with an increased risk of autism in their children, according to a new study. While these vitamins are critical, too much may be problematic. Get the details in the B-12 and Folate sections of the B Vitamin Supplements Review >>
10/22/2016

Too Much Folate & Nerve Damage

One quarter of American men and women have a gene variation which puts them at higher risk of nerve damage if consuming too much of folate (vitamin B-9) daily, according to a new study. Considering that most older Americans consume more than this amount (largely due to excessive supplement use) this should be a warning to many. For more details, see the "Folate" section of the B Vitamins Review >>
11/20/2011

No Benefit of Niacin with Statins

According to a recently published study, high dose niacin added to statin drug treatment does not further reduce the risk of heart attacks and stroke despite improvements in levels of HDL cholesterol and triglycerides. In fact, there was a small increase in strokes among those taking niacin. However, a role remains for high dose niacin in lipid treatment. For details, see the update to the B Vitamin Supplements Review.
3/17/2013

Concern Over Niacin

You may have heard that a recent study suggests that supplementing with niacin at high doses does more harm than good. This appears to be true in only certain situations. Get the facts in the update to the B Vitamin Supplements Review >>
4/14/2013

Concern Over Carnitine Causing Cardiovascular Disease

Intake of L-carnitine from supplements (and from red meat) may foster atherosclerosis (hardening of the arteries), according to new research. Once ingested, L-carnitine is converted in some people to a compound which reduces the normal clearing of cholesterol from arteries.

For more details, see the updated reviews of B Vitamin Supplements & Energy Drinks and Protein Powders, as some of these products contain L-carnitine. The Acetyl-L-Carnitine Supplements review has also been updated because acetyl-L-carnitine is chemically similar to L-carnitine, suggesting a potential concern.
1/19/2014

Multivitamin Lowers Cataract Risk

A large, long-term study using a low-dose multivitamin found that it reduced the risk of developing cataract (a clouding of the lens of the eye) by 9% compared to placebo. Interestingly, the reduced risk of cataract was negated when a separate vitamin C supplement was also taken. For details about the study and dosage, as well as our tests and comparison of multivitamins, see the updated Multivitamin and Multimineral Supplements Review >>   

For more information about cataracts and supplements, see the Cataracts article in the Conditions section of ConsumerLab.com's Encyclopedia of Natural Products.
5/24/2015

Fish Oil Increases Muscle/Strength

Last week we reported that vitamin D could help increase strength -- this week it's fish oil. A recent study found that taking a high dose of fish oil led to increases in muscle and strength in older individuals -- without additional exercise. As reported earlier, a lower of dose of fish oil may improve results of exercise. For the details, including specifics about the fish oil used, see the Fish Oil Supplements Review >> 
10/08/2014

Energy Drinks: Athletic Performance & Side Effects

A recent study found that a caffeinated energy drink improved athletes' self-perceived muscle power, but also increased insomnia and nervousness. Get the details in the update to the B Vitamin Supplements and Energy Drinks Review >> 
10/14/2015

Calcium Supplements Increase Kidney Stone Growth

Calcium supplementation is known to increase the risk of kidney stones in postmenopausal women. A new study shows that taking calcium nearly doubles the monthly growth of such stones in women prone to getting them. The study also assessed the effects of vitamin D supplementation. Details are found in the Calcium Supplements Review >>
7/05/2016

Folic Acid Supplementation Mitigates Alzheimer's

A recent study in people with Alzheimer's disease found that folic acid supplementation decreased inflammation and slightly improved mental functioning. However, participants began the study unusually low in folic acid relative to normal U.S. levels. For more details see the B Vitamin Supplements Review >> Also see results of a folate/B-12 study which showed reduced brain shrinkage in Alzheimer’s patients.
8/05/2012

Be Careful with Iodine -- Especially If You're Pregnant

Unlike over-the-counter medicines, dietary supplements are generally not required to carry warning labels, even if they contain toxic amounts of ingredients. If you don't know how much of a vitamin, mineral, or other ingredient you really need, it's easily possible to get too much. This is what seems to have happened to some pregnant women taking a widely-sold iodine supplement, according to a recent medical report. Just one tablet contained 57 times the daily iodine they needed and more than ten times the limit associated with increased risk of toxicity. Their children were born with congenital hypothyroidism, apparently due to getting too much iodine from their mothers.

Find out which product these women took in the updated Iodine section of the Multivitamin Supplements Review. You'll also find appropriate levels of other vitamins and minerals and see which products in the Review did or did not exceed tolerable intake levels of vitamins and minerals. More >>
2/22/2017

Does Your Multivitamin Have Too Much Folic Acid?

Folic acid is in multivitamins because it is provides the essential B vitamin, folate. Getting too much folate, however, carries risks. What most people don't know is that you actually get 70% more folate from folic acid than labels currently reveal and many supplements expose you to amounts of folate which are not only way above what you need but over the daily limit for tolerable intake. Companies now have until mid-2018 or later correct their labels, but until then you may be in the dark.

To find out which multivitamins exceed the tolerable limit for folate, see the update in the Multivitamins Review. You'll also learn how the daily requirements for many other nutrients have changed and differ from what labels currently tell you.
9/06/2017

Lower Cognitive Function in Kids Linked to High Prenatal Folic Acid

Children of mothers who took high amounts of folic acid around the time of pregnancy had lower cognitive and verbal scores when tested at 4 to 5 years of age, according to a new study. Similarly, as we reported last year, pregnant women with higher levels of folate (from folic acid) had offspring with higher rates of autism. While it is important that pregnant women get a moderate amount of folic acid to prevent spinal cord defects, higher amounts should be avoided. See the Folate section of the B Vitamin Supplements Review for details.

News Releases (149)

Search term may appear only in full report available to members. Sign in or Join now for full access.