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Diabetes and Dietary Supplements

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What’s the Bottom Line?

How much do we know about dietary supplements for diabetes? 

  • Many studies have investigated dietary supplements for preventing or treating type 2 diabetes or its complications (the focus of this fact sheet).

What do we know about the effectiveness of dietary supplements for diabetes?

  • For a few dietary supplements, there is weak evidence of a possible benefit. For example, chromium might help with blood sugar control, and alpha-lipoic acid might be helpful for diabetic neuropathy (nerve problems). For most supplements, however, there isn’t evidence to support a beneficial effect on diabetes or its complications. 

What do we know about the safety of dietary supplements for diabetes?

  • Some dietary supplements may have side effects, and some of these side effects, such as kidney damage, can be serious. 
  • The U.S. Food and Drug Administration (FDA) is warning consumers about products for diabetes that seem too good to be true, such as those that claim to be a “natural diabetes cure” or to “replace your diabetes medicine.” These products are marketed illegally. Some are harmful in themselves, and all are harmful if people use them in place of effective diabetes treatment.
  • It’s very important not to replace medical treatment for diabetes with an unproven health product or practice.

About Diabetes

  • Diabetes is a disease that occurs when your blood glucose, also called blood sugar, is too high. Over time, having too much glucose in your blood can cause health problems. 
  • About 9.4 percent of the people in the United States have diabetes, but about one in four people who have diabetes don’t know it.
  • Although diabetes has no cure, people with diabetes can take steps to manage their condition and stay healthy. Taking insulin or other diabetes medicines is often part of treating diabetes, along with healthy food choices and physical activity. 

More About Diabetes

  • The most common type of diabetes is type 2 diabetes, in which your body does not make or use insulin well. This type of diabetes occurs most often in middle-aged and older people, but it can develop at any age, even in childhood.
  • You are more likely to develop type 2 diabetes if you are 45 years old or older, have a family history of diabetes, or are overweight. Physical inactivity, race, certain health problems such as high blood pressure, having prediabetes, or having had gestational diabetes while pregnant also affect your likelihood of developing type 2 diabetes.
  • For more information about diabetes and related conditions, see the National Institute of Diabetes and Digestive and Kidney Diseases Web site

 

Kidney disease has been linked to using some dietary supplements. This is of particular concern for people with diabetes, since diabetes is the leading cause of kidney disease. If you have or are at risk for kidney disease, a health care provider should closely monitor your use of supplements. 

What the Science Says About the Effectiveness and Safety of Dietary Supplements for Diabetes

Alpha-Lipoic Acid 

  • Alpha-lipoic acid is being studied for its effect on complications of diabetes, including diabetic macular edema (an eye condition that can cause vision loss) and diabetic neuropathy (nerve damage caused by diabetes). 
    • In a 2011 study of 235 people with type 2 diabetes, 2 years of supplementation with alpha-lipoic acid did not help to prevent macular edema. 
    • A 2016 assessment of treatments for symptoms of diabetic neuropathy that included 2 studies of oral alpha-lipoic acid, with a total of 205 participants, indicated that alpha-lipoic acid may be helpful.
  • Safety
    • High doses of alpha-lipoic acid supplements can cause stomach problems. 

Chromium

  • Found in many foods, chromium is an essential trace mineral. If you have too little chromium in your diet, your body can’t use glucose efficiently. 
    • Taking chromium supplements, along with conventional care, slightly improved blood sugar control in people with diabetes (primarily type 2) who had poor blood sugar control, a 2014 review concluded. The review included 25 studies with about 1,600 participants. 
  • Safety
    • Chromium supplements may cause stomach pain and bloating, and there have been a few reports of kidney damage, muscular problems, and skin reactions following large doses. The effects of taking chromium long-term haven’t been well investigated. 

Herbal Supplements 

  • We don’t have reliable evidence that any herbal supplements can help to control diabetes or its complications. 
    • There are no clear benefits of cinnamon for people with diabetes. 
    • Other herbal supplements studied for diabetes include bitter melon, various Chinese herbal medicines, fenugreek, ginseng, milk thistle, and sweet potato. Studies haven’t proven that any of these are effective, and some may have side effects. 
  • Safety
    • We have little conclusive information on the safety of herbal supplements for people with diabetes. 
    • Cassia cinnamon, the most common type of cinnamon sold in the United States and Canada, contains varying amounts of a chemical called coumarin, which might cause or worsen liver disease. In most cases, cassia cinnamon doesn’t have enough coumarin to make you sick. However, for some people, such as those with liver disease, taking a large amount of cassia cinnamon might worsen their condition. 
    • Using herbs such as St. John’s wort, prickly pear cactus, aloe, or ginseng with conventional diabetes drugs can cause unwanted side effects. 

Magnesium 

  • Found in many foods, including in high amounts in bran cereal, certain seeds and nuts, and spinach, magnesium is essential to the body’s ability to process glucose. 
    • Magnesium deficiency may increase the risk of developing diabetes. A number of studies have looked at whether taking magnesium supplements helps people who have diabetes or who are at risk of developing it. However, the studies are generally small and their results aren’t conclusive. 
  • Safety 
    • Large doses of magnesium in supplements can cause diarrhea and abdominal cramping. Very large doses—more than 5,000 mg per day—can be deadly.
  • For more information on magnesium, see the Office of Dietary Supplements (ODS) Magnesium: Fact Sheet for Consumers.

Omega-3s

  • Taking omega-3 fatty acid supplements, such as fish oil, hasn’t been shown to help people who have diabetes control their blood sugar levels or reduce their risk of heart disease. 
  • Fish and other seafood, especially cold-water fatty fish such as salmon and tuna, contain omega-3 fatty acids. Studies on the effects of eating fish have had conflicting results, according to two 2012 research reviews with hundreds of thousands of participants, and a 2017 review. Some research from the United States and Europe found that people who ate more fish had a higher incidence of diabetes. Research from Asia and Australia found the opposite—eating more fish was associated with a lower risk of diabetes. There’s no strong evidence explaining these differences. 
  • Safety
    • Omega-3 supplements don’t usually have side effects. When side effects do occur, they typically consist of minor symptoms, such as bad breath, indigestion, or diarrhea. 
    • Omega-3 supplements may interact with drugs that affect blood clotting.
  • For more information on omega-3 supplements, see NCCIH’s Omega-3 Fatty Acids Web page.

Selenium

  • An assessment of 4 studies involving more than 20,000 total participants found that selenium supplementation did not reduce the likelihood that people would develop type 2 diabetes.
  • Safety
    • Long-term intake of too much selenium can have harmful effects, including hair and nail loss, gastrointestinal symptoms, and nervous system abnormalities.
  • For more information on selenium, see the ODS Selenium Fact Sheet for Consumers.

Vitamins

  • Studies generally show that taking vitamin C doesn’t improve blood sugar control or other conditions in people with diabetes. However, a 2017 research review of 22 studies with 937 participants found weak evidence that vitamin C helped with blood sugar in people with type 2 diabetes when they took it for longer than 30 days. 
  • Having low levels of vitamin D is associated with an increased risk of developing a metabolic disorder, such as type 2 diabetes, metabolic syndrome, or insulin resistance, studies and research reviews from the past 5 years have found. However, taking vitamin D doesn’t appear to help prevent diabetes or improve blood sugar levels for adults with normal levels, prediabetes, or type 2 diabetes, a 2014 research review of 35 studies with 43,407 participants showed. 
  • Safety
    • Taking too much vitamin D can cause nausea, constipation, weakness, kidney damage, disorientation, and problems with your heart rhythm. You’re unlikely to get too much vitamin D from food or the sun.
  • For more information on vitamin D, see ODS’s Vitamin D: Fact Sheet for Consumers

Other Supplements

  • The evidence is still very preliminary on how supplements or foods rich in polyphenols—antioxidants found in tea, coffee, wine, fruits, grains, and vegetables—might affect diabetes. 

 

Nutrition and Physical Activity for People With Diabetes

Nutrition and physical activity are important parts of a healthy lifestyle for people with diabetes. Eating well and being physically active can help you

  • Keep your blood glucose level, blood pressure, and cholesterol in your target ranges
  • Lose weight or stay at a healthy weight
  • Prevent or delay diabetes problems
  • Feel good and have more energy.

For more information, see NIDDK’s Web page Diabetes Diet, Eating, & Physical Activity

NCCIH-Funded Research

NCCIH is supporting research on the possible effects of:

  • Components of grape skin on blood sugar control
  • Chelation therapy on heart health in people who have diabetes and have had a heart attack
  • Marijuana on the body’s metabolism and risk of developing type 2 diabetes
  • Acupuncture on painful diabetic neuropathy (nerve damage) in underserved patients.

More To Consider

  • The FDA is warning consumers not to buy illegally marketed, potentially dangerous products claiming to prevent, treat, or cure diabetes. These products make claims like “lowers your blood sugar naturally” or “inexpensive therapy to fight and eliminate type II diabetes.” They may contain harmful ingredients and the label may not tell you what you’re actually taking.
  • Fraudulent diabetes products can be especially dangerous if you use them instead of proven treatments for diabetes. Without proper disease management, people with diabetes are at greater risk of developing serious complications. 
  • Keep in mind that dietary supplements may interact with medications or other dietary supplements. To learn more, visit NCCIH’s Web page on Dietary and Herbal Supplements.
  • Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.

For More Information

NCCIH Clearinghouse

The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.

Toll-free in the U.S.: 
1-888-644-6226
TTY (for deaf and hard-of-hearing callers): 
1-866-464-3615

PubMed®

A service of the National Library of Medicine, PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. For guidance from NCCIH on using PubMed, see How To Find Information About Complementary Health Approaches on PubMed.

NIH Clinical Research Trials and You

The National Institutes of Health (NIH) has created a website, NIH Clinical Research Trials and You, to help people learn about clinical trials, why they matter, and how to participate. The site includes questions and answers about clinical trials, guidance on how to find clinical trials through ClinicalTrials.gov and other resources, and stories about the personal experiences of clinical trial participants. Clinical trials are necessary to find better ways to prevent, diagnose, and treat diseases.

National Diabetes Education Program

The National Diabetes Education Program is sponsored by NIH and the Centers for Disease Control and Prevention, with many Federal, state, and local partners. Its services include information and publications on diabetes.

En español

Telephone: 
1-301-496-3583

MedlinePlus

To provide resources that help answer health questions, MedlinePlus (a service of the National Library of Medicine) brings together authoritative information from the National Institutes of Health as well as other Government agencies and health-related organizations.

Information on diabetes
En español

Key References

All Other References

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  • Allen RW, Schwartzman E, Baker WL, et al. Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis. Annals of Family Medicine. 2013;11(5):452-459.
  • Banihani S, Swedan S, Alguraan Z. Pomegranate and type 2 diabetes. Nutrition Research. 2013;33(5):341-348.
  • Barbagallo M, Dominguez LJ. Magnesium and type 2 diabetes. World Journal of Diabetes. 2015;6(10):1152-1157.
  • Breslavsky A, Frand J, Matas Z, et al. Effect of high doses of vitamin D on arterial properties, adiponectin, leptin and glucose homeostasis in type 2 diabetic patients. Clinical Nutrition. 2013;32(6):970-975. 
  • Bush TM, Rayburn KS, Holloway SW, et al. Adverse interactions between herbal and dietary substances and prescription medications: a clinical survey. Alternative Therapies in Health and Medicine. 2007;13(2):30-35.
  • Çakici N, Fakkel TM, van Neck JW, et al. Systematic review of treatments for diabetic peripheral neuropathy. Diabetic Medicine. 2016;33(11):1466-1476.
  • Cefalu WT, Rood J, Pinsonat P, et al. Characterization of the metabolic and physiologic response to chromium supplementation in subjects with type 2 diabetes mellitus. Metabolism: Clinical and Experimental. 2010;59(5):755-762.
  • Chen C, Yu X, Shao S. Effects of omega-3 fatty acid supplementation on glucose control and lipid levels in type 2 diabetes: a meta-analysis. PLoS One. 2015;10(10):e0139565.
  • Costello RB, Dwyer JT, Saldanha L, et al. Do cinnamon supplements have a role in glycemic control in type 2 diabetes? A narrative review. Journal of the Academy of Nutrition and Dietetics. 2016;116(11):1794-1802.
  • Forouhi NG, Ye Z, Rickard AP, et al. Circulating 25-hydroxyvitamin D concentration and the risk of type 2 diabetes: results from the European Prospective Investigation into Cancer (EPIC)-Norfolk cohort and updated meta-analysis of prospective studies. Diabetologia. 2012;55(8):2173-2182.
  • Fuangchan A, Sonthisombat P, Seubnukarn T, et al. Hypoglycemic effect of bitter melon compared with metformin in newly diagnosed type 2 diabetes patients. Journal of Ethnopharmacology. 2011;134(2):422-428.
  • Gabardi S, Munz K, Ulbricht C. A review of dietary supplement-induced renal dysfunction. Clinical Journal of the American Society of Nephrology. 2007;2(4):757-765.
  • Grubbs V, Plantinga LC, Tuot DS, et al. Americans’ use of dietary supplements that are potentially harmful in CKD. American Journal of Kidney Diseases. 2013;61(5):739-747.
  • Gui Q-F, Xu Z-R, Xu K-Y, et al. The efficacy of ginseng-related therapies in type 2 diabetes mellitus. An updated systematic review and meta-analysis. Medicine. 2016;95(6):e2584.
  • Gutierrez AD, Duran-Valdez E, Robinson I, et al. Does short-term vitamin C reduce cardiovascular risk in type 2 diabetes? Endocrine Practice. 2013;19(5):785-791.
  • Han T, Bai J, Liu W, et al. A systematic review and meta-analysis of α-lipoic acid in the treatment of diabetic peripheral neuropathy. European Journal of Endocrinology. 2012;167(4):465-471.
  • Hanhineva K, Törrönen R, Bondia-Pons I, et al. Impact of dietary polyphenols on carbohydrate metabolism. International Journal of Molecular Sciences. 2010:11(4):1365-1402. 
  • Hokayem M, Blond E, Vidal H, et al. Grape polyphenols prevent fructose-induced oxidative stress and insulin resistance in first-degree relatives of type 2 diabetic patients. Diabetes Care. 2013;36(6):1454-1461. 
  • Isnard Bagnis C, Deray G, Baumelou A, et al. Herbs and the kidney. American Journal of Kidney Diseases. 2004;44(1):1-11.
  • Lungarini S, Aureli F, Coni E. Coumarin and cinnamaldehyde in cinnamon marketed in Italy: a natural chemical hazard? Food Additives & Contaminants: Part A: Chemistry, Analysis, Control, Exposure & Risk Assessment. 2008;25(11):1297-1305. 
  • Mao S, Zhang A, Huang S. Selenium supplementation and the risk of type 2 diabetes mellitus: a meta-analysis of randomized controlled trials. Endocrine. 2014;47(3):758-763.
  • Mooren FC, Krüger K, Völker K, et al. Oral magnesium supplementation reduces insulin resistance in non-diabetic subjects—a double-blind, placebo-controlled, randomized trial. Diabetes, Obesity & Metabolism. 2011;13(3):281-284. 
  • Ooi CP, Yassin Z, Hamid TA. Momordica charantia for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews. 2012;(8):CD007845. Accessed at http://www.cochranelibrary.com on December 13, 2017.
  • Reeds DN, Patterson BW, Okunade A, et al. Ginseng and ginsenoside Re do not improve β-cell function or insulin sensitivity in overweight and obese subjects with impaired glucose tolerance or diabetes. Diabetes Care. 2011;34(5):1071-1076.
  • Rude RK. Magnesium. In: Coates PM, Betz JM, Blackman MR, et al., eds. Encyclopedia of Dietary Supplements. 2nd ed. New York, NY: Informa Healthcare; 2010:527-537.
  • Schwingshackl L, Hoffmann G, Lampousi AM, et al. Food groups and risk of type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies. European Journal of Epidemiology. 2017;32(5):363-375.
  • Shishtar E, Sievenpiper JL, Djedovic V, et al. The effect of ginseng (the genus Panax) on glycemic control: a systematic review and meta-analysis of randomized controlled clinical trials. PLoS One. 2014;9(9):e107391.
  • Song Y, Cook NR, Albert CM, et al. Effects of vitamins C and E and beta-carotene on the risk of type 2 diabetes in women at high risk of cardiovascular disease: a randomized controlled trial. American Journal of Clinical Nutrition. 2009;90(2):429-437.
  • Tovar RT, Petzel RM. Herbal toxicity. Disease-a-Month. 2009;55(10):592-641.
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  • Woehrlin F, Fry H, Abraham K, et al. Quantification of flavoring constituents in cinnamon: high variation of coumarin in cassia bark from the German retail market and in authentic samples from Indonesia. Journal of Agricultural and Food Chemistry. 2010;58(19):10568-10575.
  • Xu H, Williams KM, Liauw WS, et al. Effects of St. John’s wort and CYP2C9 genotype on the pharmacokinetics and pharmacodynamics of gliclazide. British Journal of Pharmacology. 2008;153(7):1579-1586.
  • Yin RV, Lee NC, Hirpara H, et al. The effect of bitter melon (Mormordica charantia) in patients with diabetes mellitus: a systematic review and meta-analysis. Nutrition & Diabetes. 2014;4:e145.

Acknowledgments

NCCIH thanks D. Craig Hopp, Ph.D., and David Shurtleff, Ph.D., NCCIH, for their contributions to the 2018 update of this publication.

This publication is not copyrighted and is in the public domain. Duplication is encouraged.

NCCIH has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your health care provider(s). We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by NCCIH.

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NCCIH Pub No.: 
D416
Last Updated: 
May 2018

This page last modified May 30, 2018