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Question: What is the difference between forms of vitamin K2?
Answer: Two forms of vitamin K2 are typically found in supplements: MK-4 (synthetic) and MK-7 (natural, from natto). There are significant differences between them: in paticular, MK-7 has a longer half-life, so a smaller dose can be used. Two newer forms of MK-7 are available that are synthetic. Get the details in the Review of Vitamin K Supplements, which includes our tests and comparisons of products containing both forms of K2 as well as vitamin K1.
Question: Is it better to get vitamins from foods or supplements, and are natural vitamins better than synthetic vitamins?
Answer: It is generally best to get your vitamins (as well as minerals) naturally from foods or, in the case of vitamin D, controlled sun exposure. For example, recent research on the mineral calcium suggests that it is safest to get your calcium from foods that are naturally rich in calcium than from supplements. Older women who get high amounts of calcium from supplements seem to have a higher risk of kidney stones, strokes, and even a greater risk of dying over periods of time. A small increased risk of death has also been seen in studies of people taking supplements containing vitamin A and beta-carotene compared to those who did not.
Exceptions to the "foods are better" rule are two B vitamins. Ten to thirty percent of older people don't properly digest and absorb natural vitamin B-12 from foods, so it is recommended to get B-12 from a supplement if you are over age 50. Folic acid (vitamin B-9) from supplements and fortified foods is absorbed better -- about 70% better -- than folate from regular foods such as spinach. Consequently, pregnant woman are advised to get folic acid from a supplement (or fortified food) as well as regular foods. Also keep in mind that if you get your iron from plant foods, it is absorbed only half as well as iron from meat -- although eating your spinach (or iron supplement) with a source of vitamin C will boost the absorption of its iron.
Using supplements made from whole foods won't necessarily give you more vitamins (in fact, they typically contain more modest amounts of vitamins than other dietary supplements), but you will get other plant compounds which could be of potential benefit (as well as some grams of fiber if you are consuming, for example, spoonfuls of a whole food powder as opposed to a pill). Paying a premium price for this, however, may not be worthwhile and ConsumerLab.com has found lead contamination in some whole food and "greens" products.
Regarding natural vs. synthetic forms of vitamins in dietary supplements, sometimes natural is better, sometimes synthetic is better, and sometimes it doesn't matter. Keep in mind that all can help prevent or treat deficiencies and other conditions, and nearly all are known to be harmful at too high a dose.
Natural may be better in the case of vitamin E. At low doses, either natural (d-alpha-tocopherol) or synthetic (dl-alpha-tocopherol) can be fine, although you need more IUs of synthetic (1.6 IU) to get the same amount of active vitamin E as from 1 IU of natural vitamin E. There is also a greater risk of bleeding problems with synthetic vitamin E at high doses, so that the upper limit for vitamin E for adults is 1,100 IU of synthetic vitamin E, but 1,500 IU of natural vitamin E. Naturally, vitamin E also contains other tocopherols and tocotrienols, which may have benefit. However, ConsumerLab.com tests show that not all "natural" vitamin E products contain these additional natural compounds.
Natural may also be better with vitamin K. A form of vitamin K-2, known as MK-7, naturally derived from fermented soy beans and used in supplements is better at raising vitamin K levels than supplements with synthetic K-1 or synthetic K-2, known as MK-4.
Natural or synthetic sources are both fine for getting vitamin C. Rose hips or acerola or synthetically produced vitamin C all provide the same compound -- ascorbic acid. The inclusion of citrus bioflavonoids (naturally present or added) may improve absorption.
Sometimes synthetic forms of vitamins offer advantages over natural forms. A synthetic form of niacin (vitamin B-3) called inositol hexanicotinate, for example, causes less flushing of the skin than niacin.
Use the links above to get more information about each vitamin or mineral, including ConsumerLab.com's tests and reviews of supplements containing those nutrients. For recommended daily intakes of these and other vitamins and minerals also see the Recommended Daily Intake tables, which includes upper intake limits.
Question: Sometimes my powdered supplements get clumpy. Should I be concerned?
Question: Are supplements which claim increased absorption or improved bioavailability telling the truth? Is it worth paying more for these? Are there concerns?
It is true that some supplements contain special ingredients, or enhancers, which can improve the absorption or bioavailability (amount of ingredient circulating in your blood) of certain supplements, such as CoQ10, curcumin, milk thistle, green tea, grape seed, ginkgo, and resveratrol. Enhancers typically act in the gut to either improve solubility or reduce the amount of enzymatic breakdown which occurs there. By allowing you to absorb more active ingredient, the supplement may be more potent, meaning that a smaller dose may be used. At the same time, enhancers may increase the absorption or otherwise interact with other supplements or drugs which you take, so it is important to use caution.
The four main types of enhancers currently found in supplements are emulsifying agents, like lecithin; self-emulsifying systems, which involve an oil; phytosomes made from phosphatidylcholine; and enzyme inhibitors, like black pepper extract. Liposomes and nanoparticles have also shown promise for improving absorption. Pros and cons of these enhancers, and the types of ingredients with which they may be useful, are discussed below (and in many of ConsumerLab.com's Product Reviews). See the full answer >> >>
Question: Which supplements are important after bariatric surgery (i.e., weight loss or stomach-reducing surgery)? Are there any I should avoid?
Answer: Weight loss surgeries such as gastric bypass, gastric sleeve, and gastric band procedures, reduce the amount of food and liquid a person comfortably digest in one sitting, leading to smaller meals and potentially, inadequate nutrient intake. Gastric bypass (re-routing around the stomach) and gastric sleeve surgery (removing a portion of the stomach) also reduce stomach acid and normal digestive action, leading to reduced absorption of various vitamins and minerals. The use of supplemental vitamins and minerals is recommended for gastric bypass and gastric sleeve patients, and sometimes for gastric band patients. However, for bypass and sleeve patients, the changes in digestion and nutrient absorption also mean that some supplements may not be tolerated or absorbed as well as others. For details about supplements to take or avoid, see the full answer >>
Question: Are enteric coated supplements better than non-enteric coated ones?
Answer: Enteric coatings help protect supplement ingredients from being released in the stomach and keep them away from stomach acid and enzymes. This allows the supplement to stay intact until it reaches the less acidic small intestine (where most nutrient absorption takes place). An enteric coating may also be desirable for ingredients which, for some people, otherwise cause an unpleasant aftertaste. Consequently, with ingredients that need protection it is sometimes worthwhile to purchase an enterically coated supplement. However, enteric coatings are not always necessary or beneficial, and, in some case, may just be an expensive gimmick. There are also some concerns about enteric coatings of which you should be aware. See the full answer (with information about enteric coatings for fish oil, marine oils, probiotics, garlic, and SAMe)>>
Question: Which supplements can help lower cholesterol and keep my heart healthy? Are there any to avoid?
Answer: Heart disease remains the leading cause of death for both women and men in the U.S. Some supplements may help keep your heart healthy, but others may potentially contribute to heart disease.
Heart Healthy Supplements:
There is strong evidence that sterol esters (like the phytosterol beta-sitosterol) and stanol esters, available in supplements and in some "heart healthy" margarines and spreads, can significantly lower LDL cholesterol. (There is also some evidence that taking curcumin may increase the cholesterol-lowering effects of phytosterols.) You can get more information about this, plus our tests and reviews of products in the Cholesterol-Lowering Supplements Review >>
Garlic has been shown to reduce total cholesterol and triglycerides, and may slow the development of atherosclerosis. One brand of garlic in particular has been shown to lower triglycerides more than others. You can get more information about these, including our tests and reviews of products in the Garlic Supplements Review >>
Replacing some saturated fat in the diet with olive oil may help lower risk factors for heart disease, such as high blood pressure and high cholesterol. You can get more information about extra virgin olive oil and see our Top Picks among products in the Extra Virgin Olive Oil Review >>
Oats and oat-based cerealscan be a good source of soluble fiber, which can help to lower cholesterol reduce the risk of heart disease. See our Oat Cereals Review for the clinical evidence, including how much you need to consume in order to significantly reduce cholesterol.
Soy protein, in adequate dosage, has been shown to modestly lower total cholesterol and improve LDL/HDL ratio. Preliminary research suggests lunasin, a specific protein peptide isolated from soy, may play a major role in soy's effects. Our Review of Cholesterol-Lowering Supplements includes information about these and other supplements for reducing cholesterol — also see the Soy article.
Some, but not all studies suggest that pantethine (which is not a B vitamin but is often included as an ingredient in B vitamin supplements) may help to lower LDL cholesterol.
CoQ10 has been shown to significantly reduce the risk of adverse cardiovascular events by 50% in people with moderate to severe heart failure, and may be helpful in reducing some of the side-effects of cholesterol-lowering statin drugs. You can get more information about CoQ10 (and ubiquinol, a related compound), including our tests and reviews of products, in the CoQ10 and Ubiquinol Supplements Review >>
Vitamin D may lower the risk of cardiovascular disease in those with low blood levels of vitamin D but not be of benefit for people who do not have a vitamin D deficiency. You can get more information about vitamin D, including our tests and reviews of products in the Vitamin D Supplements Review >>
Certain probiotics may modestly lower systolic and diastolic blood pressure, and "bad" LDL cholesterol — although they do not appear to increase "good" HDL cholesterol. There is mixed evidence as to whether probiotics reduce triglyceride levels. More information, plus our tests of popular products, is found in the Probiotic Supplements and Kefirs Review >>
Supplements That May Be Harmful: Vitamin E supplements, once touted for heart health, have not been found to provide a benefit for people with cardiovascular disease, and could actually be harmful for some heart disease patients, since they could reduce the effectiveness of cholesterol-lowering agents.
There is reason to believe that L-carnitine and lecithin could actually contribute to atherosclerosis in certain people, and it may be wise to avoid long-term supplementation with either one.
Supplements That May Not Help: Calcium -- Although getting sufficient calcium may decrease your risk of dying fromcardiovascular disease, too much may be harmful. A study found that calcium (800 mg) given once daily to post-menopausal women with high cholesterol caused a significant increase in serum cholesterol (up by about 50 mg/dL) and an increase in the thickness of lining of the carotid artery - changes associated with heart disease. Only if you don't get enough calcium should you consider a supplement, and it generally recommended that calcium supplementation not exceed 500 mg per dose, or more than 900 mg per day. You can get more information about these supplements, including our tests and reviews of products, in the Calcium Supplements Review >>
Fish Oil -- Despite the fact that omega-3 fatty acids that have been linked to some heart healthy effects, it seems that the benefits come from consumption of fish, and not supplements. Only if you don't eat fish might fish oil supplements provide some heart benefit. Also, because fish oil supplements can have a blood-thinning effect, they should be used with caution in people taking other blood-thinning supplements or medications. You can get more information about these supplements, including our tests and reviews of products, in the Fish/Marine Oil Supplements Review >>
Policosanol -- Although there is some evidence from several studies from Cuba suggesting a cholesterol-lowering effect, other studies have failed to find this effect, as noted in our Cholesterol-Lowering Supplements Review>>
Question: I take levothyroxine (Synthroid), a thyroid hormone to treat hypothyroidism. Are there supplements I should avoid, or be taking, due to this drug?
Answer: Levothyroxine (Synthroid, Levoxyl), liothyronine (Cytomel), and other thyroid hormone drugs for hypothyroidism (underactive thyroid), can be affected by taking supplements and can affect your ability to absorb certain vitamins and minerals. These interactions are explained in the Hypothyroidism article in the Conditions section of our website, and Thyroid Hormone article, which is part of the extensive Drug Interactions section (where you can look up interaction for other drugs you may be taking). Care must be taken with regard to using these supplements, which include calcium, iron, and soy (including soy protein powders and soy isoflavones -- found in some menopause supplements) (which can affect absorption of thyroid hormone drugs), alpha-lipoic acid (which may lower levels of thyroid hormone T3 and increase levels of TSH) and L-carnitine and acetyl-l-carnitine (which can inhibit the activity of thyroid hormones -- and may help people with hyperthyroidism, or overactive thyroid).
Resveratrolhas been shown to increase TSH levels and cause thyroid enlargement in animals, although it's not known whether it effects thyroid function in people.
Long term exposure to high or even moderate amounts of lithium can affect thyroid function.
Also, be aware that some thyroid-boosting supplements, including herbal supplements, have been found to contain thyroid hormones at significant levels, which are not listed and may be due to drug spiking. See the details in our Warnings section.
Certain foods and drinks may also interfere with absorption or bioavailability of levothyroxine. Soybean flour, cottonseed meal, walnuts, and dietary fiber may bind and decrease the absorption of levothyroxine from the gastrointestinal tract; grapefruit juice may delay the absorption and reduce its bioavailability (Synthroid Prescribing Information 2017). There is also some evidence that drinking coffee at the same time as taking levothyroxine can reduce intestinal absorption of this drug; the evidence suggests it may be best to wait one hour after taking levothyroxine before drinking coffee (Benvenga, Thyroid 2008; American Thyroid Association).
Cruciferous vegetables such as broccoli, brussel sprouts and cabbage contain compounds that can interfere with thyroid function. However, these compounds appear to be deactivated in vegetables that are cooked (McMillan, Hum Toxicol 1986).
Question: How much calcium from supplements is too much?
Answer: Maintaining adequate calcium intake is important for bone and cardiovascular health. However, getting too much calcium, particularly from supplements, can be harmful, and has been associated with an increased risk of prostate cancer, kidney stones, and heart attack -- especially in post-menopausal women. Getting too much calcium from supplements has also been associated with an increased risk of age-related macular degeneration. Use of calcium supplements may increase the risk of dementia in elderly women who have evidence of cerebrovascular disease or who have a history of stroke.
For adults over age 50, 1,200 mg is the recommended daily intake of calcium from food and supplements combined (for adults under 50, it's 1,000 mg, while for older kids and teenagers it's 1,300 mg). If you can get it all from food, great. If you can get most of it from food, then limit your calcium supplement to just the amount you need. It is generally felt that calcium supplementation should not exceed 500 mg per dose and no more than 900 mg per day.
More information about calcium, including amounts of calcium in foods and our tests of calcium supplements, is found in the Calcium Supplements Review >>
Question: I was surprised when my doctor told me to stop taking supplements because my kidney function was low. But after stopping the supplements, my kidney function returned to normal. Can taking a lot of supplements really damage the kidneys?
Answer: The effect of supplements on kidney health depends, in part, on an individual's underlying health issues, and which supplements are taken. However, there are reports of certain supplements causing kidney problems. A 2012 review of supplement-induced kidney dysfunction lists 15 herbs and supplements reported to have caused kidney problems, including chromium, creatine, licorice, willow bark, vitamin C and yohimbe (Gabardi, Clin J Am Soc Nephrol 2012).
Taking high doses of vitamin C (1 gram or more daily), for example, has been associated with an increased risk of kidney stones, especially in people with a history of kidney stones (see the Cautions section of the Vitamin C Review for more information). Supplementation with cranberry tablets may pose a similar risk in people with a history of kidney stones (Terris, Urology 2001).
In diabetes patients with advanced kidney disease, high daily doses of B vitamins (folate, B6 and B12) were found in one study to worsen kidney function and double the risk of heart attack stroke and death (see the Cautions section of the B Vitamins Reviewfor more information).
If you are on an immunosuppressive drug, taking very large amounts of turmeric/curcumin may lead to kidney damage -- possibly due to reduced metabolism of the drug).
The National Kidney Foundation advises people with kidney disease, people who are on dialysis, and people who have received a kidney transplant to avoid all herbal supplements, and provides a list of supplements that may be the most harmful. The foundation also warns that some minerals, like potassium, may be present in supplements in which you may not expect them, like turmeric rhizome, evening primrose, noni and garlic leaf can all contain potassium.
Heavy metal contamination from supplements is another potential cause of kidney problems (Gabardi, Clin J Am Soc Nephrol 2012). Long-term exposure to excessive cadmium (which accumulates in kidneys), for example, can cause irreversible kidney damage and may also weaken bones. ConsumerLab.com has reported surprisingly high concentrations of cadmium in some popular cocoa powders. To avoid unnecessary exposure, it's best to use supplements that have been tested by an independent testing organization, like ConsumerLab.com, to be sure that a supplement does not exceed heavy metal limits.
Question: I have low blood pressure. Are there any supplements I should avoid?
Answer: Certain supplements can cause decreases in blood pressure and should be used with caution if you already have low blood pressure. These are melatonin, arginine and large doses of magnesium. High doses of cannabidiol (CBD) can cause a modest decrease in blood pressure. Calcium may also cause a very small decrease in blood pressure. Preliminary studies have found black cohosh may lower blood pressure in animals, but it is unclear whether it has this effect in people.
There are also a number of supplements that have been shown to lower blood pressure in people with hypertension (high blood pressure). These include fish oil and omega-3 fatty acids, garlic, potassium, flaxseed, certain strains of probiotics, and green coffee bean extract. While much of the evidence for these is focused on people with high blood pressure, they could potentially lower blood pressure in others. So, if you take one of these supplements and find your low blood pressure becomes even lower, try eliminating the supplement and see if your blood pressure improves.
Note that sexual enhancement supplements with undeclared drugs, such as sildenafil (Viagra) or tadalafil (Cialis) may also lower blood pressure (see the list of Recalls and Warnings for supplements found to contain these drugs).
For more about using these supplements, including the evidence, potential side effects, and our tests of products, use on the links above.
Question: Is there cause for concern with "gummy vitamins?" There are many different gummies out there. Are some better than others?
Answer: Tests by ConsumerLab.com have found that some gummy supplements -- particularly gummy multivitamins -- do not contain their listed amounts of vitamins or minerals, or contain impurities. We continue to find more problems with candy-like vitamins like gummies than with traditional forms, such as tablets and caplets.
Manufacturing challenges associated with candy-like products likely explain the higher incidence of problems. Gummies are notoriously difficult to manufacture because it is hard to measure in the correct amounts of vitamins and minerals (some are simply sprayed on a candy base) and the ingredients in a gummy are more likely to degrade, so manufacturers often put in more than the listed amount -- resulting in products with too much of a vitamin, such as folic acid, when first produced and decreasing amounts over the course of their shelf-lives. Some companies seem to do a better job making gummy vitamins than others.
A benefit of gummies is that they may be more palatable than a pill. Also, being chewable, there is not the risk that the product won't properly break apart, as there is with a tablet.
A risk with any candy-like supplement, particularly for children, is that too many will be consumed, potentially resulting in toxicity. It's therefore best to give young children vitamins as needed and not leave them out. Also, keep in mind that not all vitamins, minerals, and other ingredients are easily incorporated into gummies or are not included due to poor taste (such as iron, which would cause a metallic taste), so, if you are interested in a gummy supplement, check that it lists the ingredients you want. You can check the ingredients in gummy supplements in "Ingredients" table in each of our reports listed above.
Question: Does Prevagen really improve memory?
Answer: According to the company's website, people who use people Prevagen (Quincy Bioscience) can "experience improved memory, a sharper mind, and clearer thinking. However, a review of the evidence indicates that these effects are not well substantiated. In addition, the FDA has warned Quincy Bioscience in the past against claiming Prevagen could treat conditions such as head injuries and Alzheimer's disease and for failing to report adverse reactions. The FDA has also claimed that the key ingredient, apoaequorin, a synthetic protein, is not an acceptable ingredient in a dietary supplement.
For a more detailed look at the evidence, safety, ingredients, and history of Prevagen, see the full answer >>
Question: Can taking fish oil or calcium supplements increase my risk of prostate cancer? My doctor recommended that I stop taking them since I have an enlarged prostate.
Answer: The evidence regarding fish oil and prostate cancer is mixed: some observational studies have found an increased risk among men with high blood levels of omega-3 fatty acids DHA and EPA, but fish oil supplementation has not been found to increase the risk of prostate cancer. There are studies currently underway that are investigating this issue.
Similarly, the research on calcium supplementation and prostate cancer is far from conclusive. However, the evidence suggests that most men over the age of 50 can probably get all the calcium they need from foods and should limit their total intake from foods and supplements.
Question: Which supplements help reduce the risk of colorectal cancer?
Answer: There is good evidence that getting adequate folate and fiber from foods and supplements can reduce the risk of developing colorectal cancer. (Listen to ConsumerLab.com's Fiber Supplements Webinar for more on fiber and colon health).
In people with low blood levels of selenium, selenium supplements have been found to reduce the risk of colon cancer, and in people who smoke, taking curcumin can reduce early changes in the colon that can lead to cancer.
Maintaining higher levels of vitamin D in the body -- which can be achieved through exposure to sunlight or obtained from foods and supplements -- is associated with a reduced risk of developing colorectal cancer.
Although preliminary research had suggested that calcium supplements might reduce the risk of colon polyps or colon cancer, large clinical trials failed to show a benefit with high doses.
Observational studies have also found an association between higher olive oil intake and a reduced risk of colorectal cancer.
Green tea extract has been shown to reduce the recurrence of polyps, which can sometimes turn into colon cancer.
Although a high dietary intake of CLA (conjugated linoleic acid) from high-fat dairy foods has been associated with a reduction of colorectal cancer by up to 39% in women, it is not known if taking CLA supplements has this potential benefit.
For more information about each of these supplements, use the links above. Also see the Cancer Prevention article in our Natural Products Encyclopedia.
Question: Is calcium hydroxyapatite really better than other forms of calcium?
Answer: Calcium hydroxyapatite is a form of calcium derived from cow bone and typically includes an array of other minerals as well as bone proteins. However, it is not necessarily a safer form of calcium, as explained in the Calcium Supplements Review >>
Question: Is there a danger of getting too much calcium from Tums? I take them frequently for heartburn.
Answer: Taking Tums can significantly contribute to your daily calcium intake, and it can be easy to exceed the recommended daily intake for calcium if you take several tablets per day. Since getting more than 1,000 mg of calcium daily from sources other than food is associated with certain risks, it's important to consider how many tablets you are taking and what strength they are (i.e. regular, extra strength, "ultra," etc.). More information about this is found in the Calcium Supplements Review.
Calcium can also interfere with the absorption of certain medications and other minerals. See the Cautions section of the Calcium Review and the Encyclopedia article about Antacids for more about this.
Question: Do any supplements help for tinnitus? Is it true that some supplements can cause tinnitus?
For more information, use the links above. Also see the Encyclopedia article about Tinnitus.
Question: Is it important to take calcium and magnesium together?
Answer: No, it is not necessary to take calcium and magnesium together. In fact, if you need to take large amounts (250 mg or more) of either of these, you may be better off taking them at separate times, as they can compete with each other for absorption.
Question: Is it safer to get calcium from foods than from supplements? How about from calcium-fortified orange juice and non-dairy milks?
Answer: In general, it appears to be preferable to get most of your calcium from foods which contain it naturally, and to restrict the amount you get from supplements (including calcium-fortified drinks and foods like orange juice, soy milk, almond milk, and even calcium-fortified milks like certain lactose-free milks — which are like taking a supplement with food). For example, getting too much calcium from supplements has been associated with an increased risk of kidney stones, heart attack and death in women, and an increase in the risk of heart attack in men. Taking calcium supplements has also been associated with an increased risk of dementia in elderly women who have evidence of cerebrovascular disease or who have a history of stroke. Nevertheless, calcium from all sources counts toward the upper tolerable intake level (UL) above which the risk adverse effects increase — although it is rare to exceed this limit from food alone.
Question: Are plant-based calcium supplements, like AlgaeCal, better than regular calcium supplements?
Answer: AlgaeCal (Basic) contains calcium, magnesium and trace minerals derived from algae with added vitamin D. AlgaeCal Plus also includes added vitamins C and K, boron, and additional magnesium. Testing by ConsumerLab.com in 2011 found AlgaeCal Plus to contain a higher amount of lead (a toxic heavy metal) (5.2 mcg per daily serving of 4 capsules) than many other calcium-containing supplements. Testing in 2017 found less lead, although still higher than acceptable to CL, but also less magnesium than listed on the label.
Studies sponsored by the makers of AlgaeCal found that it increased bone mineral density in healthy men and women, although there were weaknesses to the study design. There do not appear to be any clinical studies comparing the effects of AlgaeCal to other forms of calcium, such as calcium carbonate or calcium citrate nor to other calcium + vitamin D supplements. For more about this, plus evidence for other forms of calcium, see the Calcium Supplements Review >>
CL members have contacted AlgaeCal about CL's findings of lead in its AlgaeCal product and have shared the responses they received with us. These are posted below along with our comments:
(11/17/15): We were recently informed by a CL member that AlgaeCal provided the following information in response to the member's inquiry about lead in AlgaeCal Plus. In its response, AlgaeCal appears to acknowledge the amount of lead found by ConsumerLab.com in 2011, but provides information which we consider misleading regarding how that amount of lead compares to what is found in the U.S. diet by stating:
"There are 5.2 mcg of lead in a daily dosage of 4 capsules of AlgaeCal Plus. It is just like taking a daily serving of other typical plant foods according to the FDA's publication, Total Diet Study Statistics on Elements Results (December 11, 2007): Food Amount of Lead in a 4 Ounce Serving Mixed nuts, roasted 10.2 mcg Brussels sprouts, fresh, boiled 7.9 mcg Sweet potato, fresh, baked 7.2 mcg Spinach, boiled 7.0 mcg Avocado, raw 4.5 mcg. Furthermore, the US Government's Centers For Disease Control publication 'Inorganic Lead Exposure, Metabolism and Intoxication' states that 'typical intakes of lead from food, beverages and inhaled air are in the order of 300 to 500 mcg per day.' "
The most recent Total Diet Study (FDA 2014) shows much lower amounts of lead in foods than AlgaeCal states above. The FDA found no detectable lead in peanuts or Brussels sprouts and, based 3 oz servings, only 1.1 mcg in sweet potatoes (0.013 mcg/gram or mg/kg), 0.3 mcg in spinach (0.004 mcg/g) and 0.085 mcg in avocado (0.001 mcg/g). We could not find the CDC publication referenced by AlgaeCal, but found another CDC publication (ATSDR Public Health Statement for Lead 2007) which states that, based on recent studies, "the average dietary intake of lead was about 1 microgram (a microgram is a millionth of a gram) per kilogram of body weight per day." For an adult weighing 70 kg (154 lbs), this would be 70 mcg -- nowhere near the 300 to 500 mcg stated above. In short, the amount of lead in AlgaeCal Plus is higher than in most foods and calcium supplements and adds significantly to one's intake of lead, although it would not be likely, in itself, to cause toxicity in an adult.
(6/12/18): AlgaeCal recently provided the following information in response to a CL member's inquiry about lead in AlgaeCal Plus:
"Lead is omnipresent, albeit in very minute amounts, in our environment, and thus our food. There are 0.23 ppm (0.556 mcg) of lead in a daily dosage of 4 capsules of AlgaeCal Plus. There is no extraction process with the raw Algae product, it is merely live harvested from the protected beaches, dried and ground. This is one of the many trace minerals and is far below any problematic amounts — well within international safety standards. The vast majority of environmental lead present is safely excreted from the body every day, save for times of unusually high exposure. A study of lead levels in the USA food supply, found HERE, states that "Data obtained on the lead content of milk, eggs, meat, fish, and shellfish indicate that the mean levels in these unprocessed foods varied from 0.02 to about 0.4 ppm, with the lowest level in milk." To attempt to remove this lead would damage the trace mineral content that makes AlgaeCal so effective for bone health. According to THIS Health Canada informational page, "In adults with a normal diet, 3-15% of ingested lead is absorbed into the blood by the intestine. Less than 5% of absorbed lead stays in the body". So you can see that AlgaeCal is a safe, natural way to increase bone density."
The amount of lead that AlgaeCal now claims to be in its product (0.556 mcg per 4 capsules) would pose little risk. However, it is about half the amount that ConsumerLab.com found in its most recent tests in 2017 of AlgaeCal Plus.
Question: Are there negative interactions between the following supplements I take twice each day, as well as 60 mg of beta-sitosterol with dinner: Vitamin C (500 mg), CoQ10 (100 mg), grape seed extract (100 mg), fish oil (500 mg), vitamin D3/calcium/magnesium/zinc (200 IU/333 mg/113 mg/5mg)?
Answer: You may want to cut back on the vitamin C. The required daily intake is not even 100 mg and if you already get that, taking another 500 mg or 1,000 mg may actually reverse vitamin C's ability to reduce the risk of cataracts, as noted in the Vitamin C Supplements Review.
The amounts of the other supplements you take are generally safe and are at doses which may be helpful -- depending on your health conditions. It is also good that you have broken up your intake of calcium over the day, since you can't absorb more than 500 mg at a time, as discussed in the Calcium Supplement Review.
If you have high blood pressure, be aware that one study found the combination of vitamin C and OPCs (the active component of grape seed extract) to increase blood pressure (as noted in the Safety Issues section of the article on OPCs).
The beta-sitosterol which you take is at a dose which may help with symptoms of an enlarged prostate. Be aware that beta-sitosterol is also used at a much higher dose for lowering cholesterol (by competing with cholesterol for absorption in the gut) and, at this higher dose, you would not want to take it at the same time you take the fat-soluble supplements -- vitamin D and CoQ10, both of which are best taken with a meal containing some fat.
If you take also take prescription medications, be sure to look up the supplements with which they may interact using our Drug Interactions information.
Note: ConsumerLab.com staff is not able to regularly respond to requests from members to evaluate their supplement regimens. However, it tries to do so from time-to-time and often responds to questions of more general interest, such as those below.
Question: I've read of dangers from taking calcium supplements -- such as the risk of developing arterial calcifications. I can't seem to find a multivitamin without calcium. Can you help me?
As to finding a multivitamin without calcium, first be aware that most multivitamins provide less than 20% of the 1,000 - 1,200 mg adult daily requirement of calcium. There is little safety concern with this amount of calcium from a supplement if you're not getting quite enough from your diet. However, if you're sure that you get sufficient calcium from your diet and want to avoid getting more from a multivitamin, there are multivitamins that contain only tiny amounts (under 20 mg) of calcium -- usually as incidental part of another ingredient in the supplement. You can easily find products like this by comparing the amounts of calcium listed in the "Minerals" comparison table of ConsumerLab.com's Multivitamin/Multimineral Supplements Review >>
Question: Does taking one slow-release calcium tablet of 600 mg (such as Citracal) per day pose a risk for heart disease?
Answer: It depends on how much calcium you are already getting each day from other sources. As discussed in the "Heart attack risk" section of ConsumerLab.com's Calcium Supplements Review, a study determined that the risk of heart attack with calcium supplementation tends to be greater in those already getting more than 805 mg of calcium from their diet (excluding supplements).
It is generally thought that one can't absorb more than about 500 mg of calcium at time, so supplements with higher doses may not be worthwhile. However, an extended-release calcium supplement might help increase the amount absorbed. Nevertheless, 600 mg may still be more than you need.
Too much calcium also increases the risk of kidney stones, and 5% to 8% of men and women have idiopathic calciuria (too much calcium in the urine for unknown reasons), which is a risk factor for kidney stones. Even 600 mg of calcium may be too much for such people, despite a diet somewhat low in calcium, as discussed in the kidney stonessection of the report.
Also be sure you are getting adequate amounts of vitamin D, as it is necessary for your body to absorb and utilize calcium from both foods and supplements. For extensive information about vitamin D, see the Vitamin D Supplements Review.
Question: Which supplements reduce the risk of stroke? Which increase the risk of stroke?
Answer: Certain supplements have been shown to reduce the risk of stroke, while others may increase that risk. In addition, certain nutrients from foods may reduce the risk of stroke — although the benefit does not necessarily carry over to those nutrients when obtained from supplements, as discussed below. Also be aware that some supplements may increase the risk of stroke, as noted below.
Keep in mind that there are different causes of stroke. The most common type of stroke, called ischemic stroke, occurs when blood flow to a part of the brain is blocked, either by a blood clot or plaque build-up in arteries (atherosclerosis), depriving the brain of oxygen. The second, less common, type of stroke is hemorrhagic stroke, which occurs when a blood vessel inside the brain leaks blood or ruptures, creating pressure which damages brain cells. Risk factors for stroke include high blood pressure, diabetes, high cholesterol, atherosclerosis, atrial fibrillation, heart failure, and carotid artery disease (build up of plaque in the main artery in the neck which carries blood to the brain). Lack of physical exercise and being overweight, frequent use of NSAIDS (such as ibuprofen), stress and depression also increase the risk of stroke.
Supplements that may reduce the risk of stroke: (Use the links for more details such as dose.)
Getting a certain amount of vitamin D per day from food and/or supplements may reduce the risk of ischemic and hemorrhagic stroke in men, but this benefit has not been shown in women.
Folic acid (vitamin B-9) supplementation may decrease the risk of stroke in people who have very low or deficient levels of folic acid. However, be aware that there are risks associated with getting too much folate, and current supplement labels may mislead you to consume more folate than you need or is safe for you. It's also important to note that consuming high doses of other B vitamins from supplements, such as B-6 and B-12, may increase the risk of stroke, as well as heart attack and death, in people with diabetes who also have advanced kidney disease.
Nattokinase supplements may decrease blood-clotting factors in the blood, however, there are no published clinical studies in people showing that these supplements reduce the risk of blood clots (which, as discussed above, can cause ischemic stroke).
A daily dose of NAC (N-acetyl cysteine) was found to reduce the incidence of cardiovascular events, including ischemic stroke and heart attack, by 40% compared to placebo in people with end-state renal failure.
As discussed in the Encyclopedia article about Strokes, several other supplements, such as policosanol, vinpocetine and glycine have been proposed to help reduce the risk or improve recovery from stroke, although the evidence for these is not strong.
Be aware that taking a daily multivitamin has not been found to reduce the risk of stroke.
Foods that may reduce the risk of stroke:
The following types of foods may reduce the risk of stroke — although the substances in these foods have not been shown to provide the same benefit when given as supplements.
Higher intakes of calcium from foods are associated with a reduced risk of coronary artery calcification (a form of atherosclerosis), while the use of calcium supplements is associated with an increased risk.
Higher intakes of vitamin K2 from foods are also associated with a reduced risk of coronary calcification — while this benefit has not been shown from vitamin K supplements.
Eating fish has been associated with a 6% to 12% lower risk of ischemic and hemorrhagic stroke, depending on how many servings of fish per week were consumed. However, taking fish oil supplements has not been found to have the same benefit.
Getting more magnesium from your food can help reduce the risk of stroke: One study found that people who consumed more magnesium per day than average had an 8% lower risk of strokes of any kind and a 9% lower risk of ischemic stroke. However, this does not mean that magnesium supplements necessarily have the same risk-lowering effect.
In men and women at high risk for cardiovascular disease, consuming a certain amount of extra-virgin olive oildaily, as part of a Mediterranean diet was found to reduce the risk of ischemic and hemorrhagic stroke, heart attack and death by 30%.
In observational studies, drinking several cups of green tea per day was found to reduce the risk of ischemic stroke by up to 21%.
Supplements that may increase the risk of stroke:
There is concern choline from supplements and foods can increase the risk of stroke. However, a specific form of choline may help to improve recovery from stroke.
People who have had a stroke or are at risk for a stroke, should not take Ginkgo biloba.
Also, be careful if you choose to use a weight loss supplement — the FDA has issued many warnings about weight loss supplements found to contain undeclared sibutramine, a drug which can substantially increase blood pressure and pulse rate in some individuals, and may present a significant risk for people with a history of stroke (Scroll down to the "Warnings" section here for a list of some of these products).
Question: I have milk allergy and can't eat dairy. What's the best way for me to get calcium?
Answer: It can be a challenge to get sufficient calcium from your diet if you cannot eat dairy foods since they are typically the major source of calcium. For example, a cup of milk or yogurt provides 300 to 400 mg of calcium — about one-third of the daily requirement. However, other foods can provide significant amounts of calcium — although one must be aware that calcium is not well absorbed from certain plant-based foods. In addition, calcium supplements, if chosen and used properly, can help fulfill the daily requirement for calcium. See the full answer for details >>
Question: Do any supplements help reduce the symptoms of premenstrual syndrome (PMS)?
Answer: There is fairly good evidence that calcium supplements can significantly reduce the major symptoms of PMS, such as mood swings, pain, bloating, irritability, depression, back pain, and food cravings. There is also some evidence that magnesium, vitamin E, Gingko biloba, royal jelly, and chasteberry, may be helpful for reducing symptoms of PMS.
The evidence is mixed on whether or not other supplements which are commonly promoted for PMS, such as vitamin B6 and evening primrose oil, are helpful.
More about the evidence for these supplements, dosage, and information about other proposed treatments, is found in the Encyclopedia article about Premenstrual Syndrome.
In addition, be aware that women with a high intake of iron from certain sources have been shown to have a lower risk of suffering PMS than those with lower intakes -- while high intakes of potassium have been associated with an increased risk of PMS.
Question: Is it true that calcium interferes with iron absorption? Is it a problem to take a multivitamin containing both minerals?
Answer: Taking calcium can inhibit iron absorption by as much as 62%, but this depends on the dose of calcium. This interaction is of greatest concern for younger women, as they are the most likely to suffer iron deficiency. For more details about this interaction and how to avoid or minimize it, and about other minerals and foods that can inhibit iron absorption, see the "What to avoid when taking" section of the Iron Supplements Review >>
Question: After developing kidney stones, I was told to avoid tea -- but recently I've heard that green tea might actually be helpful for kidney stones. Is that true?
Answer: As discussed in the Green Tea Review, both black and green tea contain oxalate, high levels of which can contribute to the development of kidney stones in some people. However, for a number of reasons, this is not much of a concern with green tea (which may even help), and there are even ways to minimize the kidney-stone risk when drinking black tea. Get the details in the "Concerns and Cautions" section of the Green Tea Review >>
Be aware that too much calcium or vitamin C from supplements may increase the risk of kidney stones.
For information about other supplements that may be helpful or harmful regarding kidney stones, see the Encyclopedia article about Kidney Stones.
Question: What is Prelief? Does it really help for heartburn and/or bladder pain from acidic foods?
Answer: Prelief (from DSE Healthcare Solutions) is promoted as a "food de-acidfier" to reduce the acidity of foods which can trigger "painful bladder, frequent urination, indigestion, and occasional heartburn." While lowering the acidity of certain foods can potentially reduce the risk of heartburn, ConsumerLab.com found that the evidence for Prelief and its main ingredient, calcium glycerophosphate, in reducing heartburn and bladder pain is extremely limited. See the full answer >>
Question: I read an article stating that some of the ingredients in Centrum multivitamins may be dangerous or toxic. Is that true?
Answer: The safety of certain ingredients in some Centrum multivitamins - especially binders, fillers and coloring agents - has been questioned on various websites. These ingredients are not unique to Centrum vitamins but are found in many brands of multivitamins and other supplements and include polyethylene glycol, polyvinyl alcohol, BHT, modified corn starch, and coloring agents such as Yellow 6 Lake and titanium dioxide.
ConsumerLab.com has reviewed the evidence regarding the safety of these ingredients (which are listed as "Other ingredients" on supplements and as "Inactive ingredients" on medicines to distinguish them from "Active" ingredients). It is true that in amounts higher than that used in Centrum supplements, some of these ingredients can have dangerous or toxic effects. More information about these ingredients is found in our review article about Inactive Ingredients. Note that some ingredients, such as certain coloring agents, may cause allergic reactions in sensitive individuals.
In the amounts in which they occur in Centrum multivitamins, they are safe. By law, any inactive ingredient added to a supplement must be an FDA-approved food additive or generally recognized as safe (GRAS).
Centrum multivitamins also contain calcium in the form of calcium carbonate and this, too, has been mentioned as a concern on some websites. However, calcium carbonate (the form found in oyster shells and most commonly used in supplements and antacids), is not inherently unsafe. While there are some differences to consider when choosing which form of calcium to take, the potential for issues such as increased risk of heart attack with large servings of calcium and interactions with medications and other minerals is not limited to calcium carbonate, but includes any supplemental calcium.
You can check the full list of ingredients for each product tested in ConsumerLab.com's Review of Multivitamin and Multimineral Supplements (and in any of our many other Product Reviews) by clicking on "Ingredients" underneath the product name in the first column of the results table. In the results table, itself, we also point out if a product is free of artificial colors, flavors, and/or preservatives, or has other special features, such as being gluten-free.
Question: I am having trouble sleeping. I regularly take a multivitamin, fish oil, magnesium, calcium, vitamins D and K, and a protein supplement. I also take a low-dose blood pressure medication. Could any of these supplements be causing my insomnia?
Answer: Among these supplements, vitamin D seems the most likely cause. Multivitamins, fish oil, magnesium, calcium, vitamin K and protein supplements are not generally known to cause insomnia. High doses of vitamin D, as well as high blood levels of vitamin D have been associated a deterioration in sleep quality — and you seem to be supplementing with both vitamin D and a multivitamin that likely provides more vitamin D. High amounts of vitamin D may interfere with the body's production of melatonin.
Be aware that beta blocker medications, such as atenolol (Tenormin) and metoprolol (Lopressor, Toprol XL) that help lower blood pressure may also lower your body's nighttime production of melatonin and interfere with sleep. A small study suggests that melatonin supplementation may improve sleep in people taking these medications. However, be aware that melatonin may increase blood pressure in people taking another type of blood pressure lowering medication. See the Concerns and Cautions section of the Melatonin Supplements Review for more about this.
Question: Are the "% DV" numbers on vitamin supplement labels really based on what I need?
Answer: Yes and no. The most current DVs (Daily Values), updated by the FDA in 2016, do accurately reflect the basic daily intake requirements for vitamins and minerals. However, companies are not required to use the updated DVs on product labels until at least 2020. In the meantime, many vitamin and supplement labels will be misleading — providing "%DV" values based on terribly out-dated DVs establish in the 1960s. The new DVs include separate values for infants, very young children, and women who are pregnant and lactating.
Some important changes in 2016 to the DVs for most adults and children over age 4 include the following. (Keep in mind that your supplement label is most likely still based on old DVs):
Vitamin D: The DV doubled, from 400 IU (10 mcg) to 800 IU (20 mcg). (Note: Many people who are not deficient in vitamin D may already be taking too much.) Labels will also have to list vitamin D in different units (mcg), but can include the familiar IU (international units) values (1 mcg = 40 IU).
Folate: Recognizing that about 70% more folate is absorbed from supplements containing folic acid (synthetic folate) than from foods naturally containing folate, the DV (which remains at 400 mcg) is now based on "dietary folate equivalents," shown as "DFE". A supplement with 400 mcg of folic acid is to be labeled as providing 170% DV rather than 100% DV.
Tetracyclines (doxycycline (Bio-Tab, Doryx, Doxy-Caps), tetracycline hydrochloride (Achromycin V, Panmycin etc.):Calcium, magnesium, iron and zinc, Dong Quai, St. John's Wort, citrate (i.e. potassium citrate)
Trimethoprim/sulfamethoxazole (Bactrim, Cotrim, Septra, Sulfatrim): Folate, PABA (para-aminobenzoic acid), potassium, white willow, St. John's wort
Interestingly, some of the supplements noted above (folate and vitamin K) may, at times, be helpful when taking certain antibiotics, as can probiotics.
Question: Which supplements can help treat constipation?
Answer: A number of supplements may be helpful in treating or preventing constipation. Fiber supplements, such as psyllium and glucomannan (a water-soluble fiber) may help to relieve constipation (Note: there is a safety concernwhen using glucomannan). Ground flaxseed, another source of fiber, may also be helpful. (See ConsumerLab.com's Fiber Supplements Webinar for more information about these supplements for constipation as well as for other uses.)
A specific probiotic product was found to significantly increase the number of bowel movements per week in people with chronic constipation. (Other strains have been found to be helpful for constipation associated with IBS).
Magnesium and aloe vera juice (with latex) can help to relieve constipation due to their laxative effects (Note: There are safety concerns with aloe latex -- see the "Concerns and Cautions" section of the Aloe Vera Review before using).
See the Encyclopedia article about Constipation for information about other proposed treatments.
Be aware that constipation may be a side-effect of certain supplements, especially iron, and to a lesser degree, calcium (see the "ConsumerTips" sections of the respective ConsumerLab.com Reviews for more about forms of these minerals which may be less likely to have this effect). Other supplements reported to cause constipation, although less frequently, include nattokinase, chlorella, NAC (N-acetyl cysteine) and beta-sitosterol.
Excessive intake of vitamin D as a supplement can cause hypercalcemia (too much calcium in the blood) with symptoms including constipation.
Question: I've heard that soaking dried beans for 24 hours reduces the phytate level, allowing for greater access to nutrients. Is this true?
Question: I bought a lactose-free milk that is "calcium-fortified" and provides 50% of the Daily Value for calcium. Is that too much calcium?
Answer: If you drink a cup (8 fl oz) or more of milk at a time, then, yes, this milk may provide you with too much calcium. The current Daily Value for calcium is 1,300 mg. Fifty percent of the Daily Value for calcium is 650 mg of calcium, and it's generally advised that you not consume more than 500 mg of calcium in a serving.
Be aware that the Daily Value for calcium was officially increased in 2016 from 1,000 mg to 1,300 mg, and that this DV is pegged to the group with the greatest requirement for calcium -- adolescents and teenagers, while younger children and adults need less (see daily requirements by age.)Also be aware that the FDA has given companies until 2020 to change their labels to reflect the new DV. So, if your brand is still using the old DV, then 50% is 500 mg -- right at the edge of being too much calcium in a serving; if you have the milk along with calcium-containing foods or supplements, you're still getting too much calcium at one time.
You're probably better off with a lactose-free milk that is not "calcium fortified," as a cup will naturally provide about 30% of the Daily Value for calcium (390 mg based on the new DV or 300 mg based on the old one), and that's fine.
Question: Is it true that taking calcium supplements increases the risk of developing age-related macular degeneration (AMD)?
Answer: Regularly consuming too much calcium specifically from supplements or antacids has been associated with a higher risk of developing age-related macular degeneration (AMD). Calcium from foods does not appear to have this effect and may, to some extent, reduce the risk of AMD.
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Calcium Supplements Review
Intial Posting: 5/17/17 Last Update: 10/29/18
Choose the Best Calcium Supplement
See Which Calcium Supplements Passed CL's Tests & the Top Picks
Alphabetical list of calcium supplements reviewed and rated in report
AdvoCare Calcium Plus
Jarrow Formulas Bone-Up
Puritan's Pride Chelated Calcium Magnesium Zinc
Kirkland Signature [Costco] Calcium 600 mg + D3
Sundown Naturals Calcium Magnesium and Zinc
Andorra Life Collagen Calcium
Kirkland Signature [Costco] Calcium Citrate Magnesium And Zinc
Make sure the calcium supplement you take passed our review and is right for you!
Isn't your health worth it?
Confused about calcium? With so many different forms, dosages and ingredient combinations (such as calcium with vitamin D or magnesium) available, it may be hard to know which product is best for you and your family. ConsumerLab.com's new review can help you choose the highest quality calcium supplement at the best value!
Calcium is critical for building and maintaining strong bones and preventing osteoporosis. It is also needed for the proper functioning of nerves, muscles, glands, and the cardiovascular system. But you need to be careful! Getting too much calcium from supplements can your risk of heart attack and kidney stones.
ConsumerLab.com tests found problems with some combination products — including one which failed to properly disintegrate in the allotted time, and another which contained less magnesium than claimed and was contaminated with lead. Fortunately, however, we also found a number of quality products which passed our tests and provide a reasonable dose of calcium -- some of which cost less than 5 cents per day.
You must become a ConsumerLab.com member to get the full test results for calcium supplements, including quality ratings and CL's Top Picks. You will get results for 28 calcium supplements: 18 selected for testing by ConsumerLab.com and 10 others that passed the same tests through CL's voluntary Quality Certification Program as well as information about three supplements similar to ones that passed testing.
In this comprehensive report, you'll discover:
Which calcium supplements failed our quality ratings and which passed -- including combinations with vitamin D, vitamin K, and magnesium
CL's Top Picks for calcium supplements
Cost comparisons to help you choose a calcium supplement offering the best value based on amounts of elemental calcium
The pros and cons of different forms of calcium such as carbonate, citrate, gluconate, oyster shell, coral calcium and plant-based calcium --and which may be best for you
How much calcium you may already be getting from foods and other sources, such as antacids taken for heartburn
Recommendations on calcium dosage by age and gender and for specific uses, as well as how much calcium may be too much and how best to take calcium supplements
The best way to take calcium supplements and what to look for on labels
Potential drug interactions and side effects of calcium supplements
Question: I was surprised when my doctor told me to stop taking supplements because my kidney function was low. But after stopping the supplements, my kidney function returned to normal. Can taking a lot of supplements really damage the kidneys? Get the answer >>
Question: I have low blood pressure. Are there any supplements I should avoid? Get the answer >>
Question: Is there cause for concern with "gummy vitamins?" There are many different gummies out there. Are some better than others? Get the answer >>
Question: Is it safer to get calcium from foods than from supplements? How about from calcium-fortified orange juice and non-dairy milks? Get the answer >>
Question: Are plant-based calcium supplements, like AlgaeCal, better than regular calcium supplements? Get the answer >>
Question: Are there negative interactions between the following supplements I take twice each day, as well as 60 mg of beta-sitosterol with dinner: Vitamin C (500 mg), CoQ10 (100 mg), grape seed extract (100 mg), fish oil (500 mg), vitamin D3/calcium/magnesium/zinc (200 IU/333 mg/113 mg/5mg)? Get the answer >>
Question: I've read of dangers from taking calcium supplements -- such as the risk of developing arterial calcifications. I can't seem to find a multivitamin without calcium. Can you help me? Get the answer >>
Question: Does taking one slow-release calcium tablet of 600 mg (such as Citracal) per day pose a risk for heart disease? Get the answer >>
Question: Which supplements reduce the risk of stroke? Which increase the risk of stroke? Get the answer >>
Question: I have milk allergy and can't eat dairy. What's the best way for me to get calcium? Get the answer >>
Question: Which supplements can help with indigestion and/or heartburn? Get the answer >>
Question: Do any supplements help reduce the symptoms of premenstrual syndrome (PMS)? Get the answer >>
Question: Is it true that calcium interferes with iron absorption? Is it a problem to take a multivitamin containing both minerals? Get the answer >>
Question: After developing kidney stones, I was told to avoid tea -- but recently I've heard that green tea might actually be helpful for kidney stones. Is that true? Get the answer >>
Question: What is Prelief? Does it really help for heartburn and/or bladder pain from acidic foods? Get the answer >>
Question: I read an article stating that some of the ingredients in Centrum multivitamins may be dangerous or toxic. Is that true? Get the answer >>
Question: I am having trouble sleeping. I regularly take a multivitamin, fish oil, magnesium, calcium, vitamins D and K, and a protein supplement. I also take a low-dose blood pressure medication. Could any of these supplements be causing my insomnia? Get the answer >>
Question: Are the "% DV" numbers on vitamin supplement labels really based on what I need? Get the answer >>
Question: Are there any supplements I should avoid when taking an antibiotic? Are there any that may be helpful? Get the answer >>