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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: I've heard that curcumin is a MAO inhibitor. Is this true, and does that mean it is not safe to take if you eat amine-rich foods like cheese and dark chocolate?
Answer: It is true that curcumin can act as a MAO inhibitor, but this has only be demonstrated in animals when given intravenously at high doses. There are no studies on curcumin's effect on MAO inhibition in people taking oral supplements -- which have significantly lower absorption and tend to be taken in much lower doses. There are, however, certain supplements and drugs which should not be taken when using curcumin and turmeric. For more information about this, see the Concerns and Cautions section of the Turmeric/Curcumin Supplements Review>> Also see the Encyclopedia article about Curcumin>>
Question: I read that turmeric may be a GI irritant. I have GI problems and wonder if I should avoid turmeric and curcumin?
Answer: Although curcumin (from turmeric) has been shown in clinical studies to improve symptoms of indigestion and ulcerative colitis, it is true that it a small percentage of people may experience nausea, diarrhea and mild stomach distress, especially when taking high doses for prolonged periods of time. This and other concerns are discussed in the Turmeric and Curcumin Supplements Review, which includes details about dose, side-effects, tips for taking curcumin and turmeric supplements, as well as ConsumerLab.com’s tests of products. Also see the article about on Turmeric in our Encyclopedia.
Be aware that curcumin and turmeric should be avoided by people with gallstones or gallbladder disease, as these can stimulate the gallbladder.
Question: After taking a curcumin supplement, I started getting chronic diarrhea which went away when I stopped taking it. Can curcumin supplements cause diarrhea?
Answer: Yes, unfortunately diarrhea is one of the reported side-effects of curcumin supplements. The risk of diarrhea may increase with higher doses of curcumin (900 mg/day or more) or when taken for one month or longer (Sharma, Clin Cancer Res 2004). For more information, including other potential side-effects of curcumin, evidence for use, and our tests of curcumin supplements, see the Curcumin Supplements Review >>
Question: I recently read that turmeric is only effective if it is combined with black pepper. Is this true?
Answer: Black pepper is not necessary for turmeric to be effective, but it can be helpful. Black pepper contains a compound, piperine, which inhibits the metabolic breakdown of turmeric compounds in the gut and the liver. This allows higher levels of turmeric compounds to remain in the body (i.e., it increases its bioavailability), which may increase the effects of turmeric. Keep in mind that this can also affect the breakdown of other compounds, including certain drugs. You can get more details about this in the Turmeric (Curcumin) Supplements Review.
Be aware that the biggest problem with turmeric is making sure that its compounds are absorbed from the gut. You will absorb little if turmeric is not taken with along with fats or oils, which is why it's best to take turmeric and curcumin with a meal containing fats or oils. Black pepper does not help with absorption. Special formulations of turmeric and curcumin supplements have been developed to increase absorption and bioavailability of turmeric compounds. Details about these are also found Turmeric (Curcumin) Supplements Review, noted above.
Question: Is Theracurmin better absorbed than other curcumin formulas - and can it really help lower my blood pressure?
Answer: Theracurmin™ is a branded form of curcumin that has been reduced in particle size to form "nanoparticles" which are then microencapsulated. Studies of its absorption and effect on blood pressure have been conducted and are discussed, along with information about other forms of curcumin such as BCM-95, Meriva, and CurcuWin, in the Turmeric and Curcumin Supplements Review >>
Question: Is Rhodiola rosea effective for depression and does it have other uses? Will ConsumerLab.com be testing these supplements?
Answer: Evidence from small studies (including one recently supported by the National Institutes of Health) suggests that extracts made from Rhodiola rosea (also known as roseroot) may have a modest benefit in depression. It is not as effective as anti-depressant medication but poses less risk of side-effects. There is some preliminary evidence it may also be modestly helpful for people with mild anxiety. Support for some of its other proposed uses - such as fighting fatigue and improving mental acuity - has not been well established. For more about Rhodiola rosea, including the type and dosage used to treat depression, see the full answer >>
ConsumerLab.com has tested popular R. rosea supplements for quality and purity. See the results (including our top picks among Approved products), plus more about the evidence for these and other uses, such as reducing fatigue and improving athletic performance, in the Rhodiola Rosea Supplements Review.
Question: I take ubiquinol to replenish CoQ10 depleted by my statin. I also take curcumin (from turmeric). Since they both manage free radicals, do I need to take the curcumin?
Answer: Although both curcumin and ubiquinol (the activate form of CoQ10) have antioxidant properties, they have very different effects in the body, as is the case with other antioxidants, such as vitamin E and vitamin C. So taking one will not achieve all the things accomplished by the other.
CoQ10 is used for energy production within cells, and levels in the body can be lowered by statin drugs. Some, but not all, evidence suggests taking CoQ10 may help reduce certain side effects of statin drugs, such as muscle pain. Curcumin, on the other hand, has anti-inflammatory effects, which may be helpful for conditions such as arthritis or muscle-soreness after exercise, but it is not known to increase energy production in cells, or reduce statin-related muscle pain.
Question: Do any supplements help with nerve pain, like sciatica or diabetic neuropathy?
Answer: Several supplements have been shown to be helpful for nerve pain caused by conditions such as sciatica or diabetic neuropathy. These include fish oil, curcumin, alpha-lipoic acid (ALA) and GLA, and benfotiamine. Read the full answer for details and dosage >>
Question: How does turmeric spice compare to turmeric (curcumin) in supplements? I sprinkle it on my foods and wonder if that's equivalent to taking a supplement.
Answer: Turmeric spice is ground (dried) turmeric herb — specifically the root/rhizome, sold as a powder. Consuming between ½ to 1 teaspoon of turmeric powder (about 2.5 to 5 grams) with food has been found to have certain digestive and cognitive benefits.
Most clinical studies, however, have not used turmeric powder, but turmeric extract. Only about 3% of the weight of turmeric powder is curcumin and "curcuminoid" compounds -- which are believed to be important to turmeric's effects. In turmeric extracts, the concentration of these is often increased to as high as 95%.
Therefore, it is not unusual for a capsule containing half of a gram of turmeric extract to provide 400 mg of curcuminoids, while the same amount of turmeric powder (ground herb -- just like the spice) might provide only about 15 mg. In fact, in 2013, ConsumerLab.com found that capsules of turmeric "herb" (not extract) from a well-known supplement brand contained only 3 mg of curcuminoids per capsule. Many brands of turmeric supplements contain a combination of extract and herb, and the ratio will greatly affect the amount of curcuminoids you get, so be sure to check the amounts of curcuminoids in popular supplements in ConsumerLab.com's Review of Turmeric and Curcumin Supplements and Spices >>.
One advantage of using tumeric spice, as opposed to a supplement, is that you are more likely to consume it with fats or oils from your food. This will enahance absorption of curcuminoids in the turmeric, as they are lipophilic (they attach to fats). You should take turmeric supplements with meals for the same reason and/or choose a supplement which includes a bioavailability enhancer (as discussed in detail in the Review).
Another way that turmeric extracts differ from turmeric powders is that extracts are less likely to be contaminated with heavy metals, such as lead, and do not contain the filth (insect parts and rodent hairs) normally found to varying degrees in the powders. In the Review, you'll also see our tests of levels of filth and heavy metals in popular turmeric spices for cooking, plus the dosage of herb or extract used in treating conditions such as ulcerative colitis, uveitis, arthritis, psoriasis, diabetes, depression, and cognitive function.
Question: Which supplements can help to lower blood pressure?
Answer: There are many supplements, including CoQ10, fish oil, curcumin, certain probiotics, cinnamon and others, which may lower blood pressure. However, if you already take medication to lower blood pressure, always consult your physician before using these supplements, as they may lower your blood pressure too much, or interfere in some other way with your current medication. Be aware that a number of supplements can increase blood pressure. Sign in to see the full answer >>
See the Encyclopedia article about Hypertension for more information.
Question: Can curcumin help prevent or improve symptoms of Alzheimer's disease?
Answer: Laboratory and animals studies have shown that curcumin inhibits several biological and chemical processes in brain cells associated with the development of Alzheimer's disease, and may act similarly to some drugs currently used to treat symptoms (Aricept, Razadyne). And, in animal models of the disease, oral supplementation with curcumin has shown some benefit. However, the few studies that have been conducted in people with Alzheimer's disease have found little benefit (although it may improve cognitive function in healthy older adults). For more details, (as well as our tests and comparisons of products) see the Turmeric and Curcumin Supplements and Spices Review >>
Question: What is phytosomal curcumin? Does it have better absorption than other curcumin formulations?
Answer: As discussed in the Curcumin Supplements Review, only a limited percentage of curcumin taken orally will be absorbed into the blood. Phytosomal formulations, such as Meriva, which combine curcumin with phosphatidylcholine (a natural surfactant that dissolves in both water and oil), can help to improve bioavailability compared to regular curcumin. Other formulations, such as BMC-95, CurcuWin, Theracurmin, and black pepper extract (Bioperine) may also improve bioavailability. More details about these and how they compare, are found in the Bioavailability section of the Turmeric and Curcumin Supplements Review >>
Question: I use a brand of curcumin and the most recent bottle contained capsules a few shades lighter than what I am accustomed to taking. Is this color change an issue to be concerned about?
Answer: Variation in the color of turmeric and curcumin can occur, even from bottle-to-bottle for the same product. This is not necessarily a problem, as explained in the "What to Consider When Buying and Using" section of the Turmeric and Curcumin Supplements and Spices Review. Most importantly, the product should provide the expected amount of curcuminoid compounds (not all do!)— which is what ConsumerLab.com has measured and published (see the "What CL Found" and "Test Results by Product" sections of the Review).
Question: How should curcumin dose be adjusted if using formulations with enhanced bioavailability such as Meriva, BCM-95, CurcuWin, Theracurmin, Bioperine, and C3?
Answer: If you're taking curcumin with just water (and not with foods containing fats or oils), these formulations can greatly increase the absorption and/or bioavailability of curcumin and other curcuminoid compounds, which will affect the dose you need to take. Find out more about each of these formulations and their suggested dosage in the "Absorption and Bioavailability" section of the Turmeric/Curcumin Review >>
Question: Is it safe to take curcumin or turmeric supplements for a long period of time?
Answer: Formal, long-term safety studies have not been conducted with curcumin or turmeric supplements, although smaller efficacy studies have not shown toxicity with fairly high doses. Side-effects, however, can occur. Keep in mind that bioavailability enhancers found in some curcumin supplements can interfere with certain medications and medical conditions. For more details, see the "Concerns and Cautions" section of the Curcumin and Turmeric Supplements and Spices Review >>
Question: Which supplements can help lower or control my blood sugar?
Answer: Many different supplements may help lower or control blood sugar in people with prediabetes or type 2 diabetes who experience hyperglycemia (when blood glucose rises higher than normal). These supplements are discussed below. More details about each, including dosage, drug interactions, potential side effects, and ConsumerLab.com's reviews of products on the market, can be found by clicking on the links.
Due to the seriousness of hyperglycemia, it is important to consult with your physician regarding use of these supplements.
Cinnamon supplements may modestly improve blood sugar in people with type 2 diabetes whose blood sugar is not well controlled with medication. In addition, one small study found that a branded cinnamon extract reduced fasting blood sugar by an average of about 10 mg/dL in prediabetic men and women with metabolic syndrome. Keep in mind, however, that only certain varieties of cinnamon have been shown to have this effect, and long-term safety studies have not been conducted.
Curcumin (from turmeric) may improve blood sugar levels, according to preliminary studies, and one study found curcumin to dramatically lower the chances of prediabetes in middle-aged, slightly overweight men and women with somewhat higher than normal blood sugar levels.
Alpha lipoic acid may improve insulin sensitivity and blood sugar control in people with type 2 diabetes, although it may only slightly reduce levels of glycosylated hemoglobin (HbA1c).
Chromium picolinate may help some people with type 2 diabetes decrease fasting blood glucose levels as well as levels of insulin and glycosylated hemoglobin (HbA1c). However, be aware that high doses may worsen insulin sensitivity in healthy people who are not obese or diabetic.
Having adequate blood levels of vitamin D may reduce the risk of insulin resistance in people who are obese. There is some evidence that a certain blood level of vitamin D is needed for normal glucose metabolism in women who are overweight and obese (but not diabetic), but it is not clear whether any further benefit is gained with higher blood levels.
In healthy people, consuming a moderate amount of olive oil with a meal has been shown to reduce increases in blood sugar after the meal compared to the same meal consumed with corn oil. In people with type 1 or type 2 diabetes, olive oil may improve glucose metabolism.
Increasing dietary fiber, especially insoluble fiber from cereal and grains, is associated with a reduced risk of diabetes and has been shown to reduce fasting blood glucose and modestly lower HbA1c in people with type 2 diabetes (Martin, J Nutr 2008; Post,J Am Board Fam Med 2012). In people with type 1 diabetes, 50 grams of dietary fiber per day has been shown to significantly improve blood sugar control and reduce hypoglycemic events (Giacco, Diabetes Care 2000). The American Dietetic Association states that "diets providing 30 to 50 g fiber per day from whole food sources consistently produce lower serum glucose levels compared to a low-fiber diet. Fiber supplements providing doses of 10 to 29 g/day may have some benefit in terms of glycemic control." (Slavin, J Am Diet Assoc 2008). Although ConsumerLab.com has not tested fiber products, we have produced a webinar about that provides more information.
Ginseng, both American and Korean Red ginseng (from Panax ginseng), may reduce blood sugar levels in people with diabetes, according to preliminary research.
Drinking whey protein before a high glycemic meal may help to lessen increases in blood sugar after the meal in people with well-controlled type 2 diabetes.
Silymarin, a component of milk thistle, may decrease blood sugar and hemoglobin A1c in people with type 2 diabetes, and reduce insulin resistance in people with coexisting diabetes and alcoholic cirrhosis.
Inulin, a type of prebiotic, may improve measures of blood sugar control in women with type 2 diabetes, although it did not improve blood sugar levels or insulin resistance in a study of prediabetic men and women.
Berberine (a compound found in plants such as barberry, Oregon grape and goldenseal) may reduce blood sugar levels in people with metabolic syndrome or type 2 diabetes, according to a few small studies.
Fenugreek may help to lower blood sugar, according to preliminary studies, and one study found fenugreek extract to significantly improve some measures of blood sugar control and insulin response in people with type 2 diabetes.
White mulberry (Moruns alba or Morus indica) has been traditionally used in Asia to help treat type 2 diabetes, and there is some preliminary evidence to support this use. Mulberry leaf extract (species not given) may lessen increases in blood sugar after ingestion of table sugar in healthy people and people with type 2 diabetes (Mudra, Diabetes Care 2007). Among people with type 2 diabetes, taking 1 gram of powdered white mulberry leaf three times daily (after breakfast, lunch and dinner) for four weeks was found to lower fasting blood sugar by 27%, while taking 5 mg of the anti-diabetes drug glibenclamide lowered fasting blood sugar by only 8% (Andallu, Clin Chim Acta 2001).
There is mixed evidence as to whether CoQ10 may lower blood sugar. To be safe, people with diabetes or who take medication to lower blood sugar should consult a physician before using.
There are a few supplements which may worsen blood sugar control or insulin sensitivity in certain people: excessive amounts of niacin may elevate blood sugar levels, and prescription digestive enzymesmay cause an increase or decrease in blood sugar levels in people with exocrine pancreatic insufficiency. CLA (conjugated linoleic acid), a popular supplement for slimming, may worsen blood sugar control in diabetics and in obese people without diabetes.
Although fish oil does not appear to adversely affect blood sugar levels in people with diabetes, one study reported that a large daily dose of krill oil (providing a modest amount of EPA and DHA) reduced insulin sensitivity in overweight, middle-aged men by about 27% -- which could potentially increase the risk of diabetes.
Also note that high doses of vitamin C may increase blood sugar or interfere with certain blood sugar tests.
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Product Review:Turmeric and Curcumin Supplements and Spices
Posted: 12/14/13 Last Update: 10/4/16
33% of Turmeric and Curcumin Supplements Selected for Testing Fail Quality Review
Find Out Now If Yours Passed!
Turmeric Spices Also Tested -- You Won't Believe What We Found!
Alphabetical list of turmeric and curcumin supplements and spices in report
Make sure the turmeric supplement or curcumin supplement or spice you use passed our review and is right for you!
Isn't your health worth it?
Supplements containing turmeric and its key compound, curcumin, may be helpful in treating inflammatory diseases and other conditions such as diabetes. However, recent tests by ConsumerLab.com found significant problems with two out of nine turmeric and curcumin products selected for testing.
Two supplements contained only 33.1% and 52.9% of their expected curcumin compounds (known as curcuminoids). In fact, one contained less than 10 mg of these compounds, while the typical dosage shown to work in studies is hundreds of milligrams! The other product was found to be contaminated with small amounts of the toxic heavy metals lead and cadmium. A third product failed to provide label information required by the FDA.
To help you get the best value from a turmeric or curcumin supplement, ConsumerLab.com calculated the cost to obtain a 500 mg dose of curcuminoids from each product. Among the top-quality supplements we identified, we found that you can get this dose for as little as 21 cents -- much less than you might expect.
Five popular, ground turmeric spice products were also tested. Several contained large numbers of insect parts, which suggests insanitary storage, and one "organic" product contained a whole insect larva! We did find one spice, however, which was exceptionally clean and not contaminated with Salmonella, lead ,or cadmium.
You must join to get the full test results for curcumin supplements and turmeric supplements and spices along with ConsumerLab.com's recommendations and quality ratings. You will get results for nine supplements and five spices selected by ConsumerLab.com and for seven other supplements that passed voluntary, quality certification testing. You'll also learn about two products similar to that was tested.
In this comprehensive report, you'll discover:
Which turmeric and curcumin supplements failed testing and which passed
Direct comparisons and quality ratings of turmeric and curcumin supplements, as well as ground turmeric spices
How the bioavailability of curcumin may be enhanced with ingredients such as Bioperine, BCM-95, and Meriva
Dosage for specific uses of turmeric and curcumin including ulcerative colitis and proctitis, osteoarthritis, uveitis, rheumatoid arthritis, psoriasis, prediabetes, and cancer
Question: Can curcumin help prevent or improve symptoms of Alzheimer's disease? Get the answer >>
Question: What is phytosomal curcumin? Does it have better absorption than other curcumin formulations? Get the answer >>
Question: I use a brand of curcumin and the most recent bottle contained capsules a few shades lighter than what I am accustomed to taking. Is this color change an issue to be concerned about? Get the answer >>
Question: How should curcumin dose be adjusted if using formulations with enhanced bioavailability such as Meriva, BCM-95, CurcuWin, Theracurmin, Bioperine, and C3? Get the answer >>
Question: Which supplements can help with indigestion and/or heartburn? Get the answer >>
Question: Is it safe to take curcumin or turmeric supplements for a long period of time? Get the answer >>
Question: Which supplements can help lower or control my blood sugar? Get the answer >>
The manufacturer of a product which failed ConsumerLab.com's review due to inadequate label information has notified ConsumerLab.com that it has updated the labeling of the product. See the Update in the full review for details.