What is chromium?
It's a metal that's much more valuable in your body than on your car. Chromium, found in tiny amounts in most foods, works like a key to unlock insulin. Without this nutrient, insulin is much less effective at controlling blood sugar, building proteins, or performing any of its other jobs. If you don't get enough chromium in your diet, you may be more likely to develop high blood sugar and high cholesterol.
Chromium is also a hugely popular dietary supplement -- and not because the nation has developed a sudden mania for well-controlled blood sugar. The demand for chromium pills -- often sold in the form of chromium picolinate -- is based on a simple and common premise: The mineral supposedly helps build muscle and burn fat. Ads for chromium supplements point to "many scientific studies" that supposedly prove the mineral's power to add wanted bulk while removing unwanted bulge. But a close look at the scientific literature shows that the short-cut to a perfect body is still a long way off.
Is there any validity to the claims that chromium supplements can build muscle or burn fat?
After roughly two decades of careful studies, researchers still aren't certain if chromium supplements have any effect on muscles but believe it is probably not effective for weight loss. While some studies have found small benefits from the supplements, others have found nothing. A 2003 review of 24 studies found that 200 to 1,000 mcg of chromium per day produced no significant benefits to body mass or composition. There continues to be controversy surrounding chromium supplements, but one point is clear: Anyone looking for instant, dramatic changes in their body shape had better look for a different magic pill.
The chromium craze got its start years ago when researchers at the U.S. Department of Agriculture reported that 200 mcg (a microgram is one-millionth of a gram) of daily chromium supplements significantly increased the lean body mass of college football players and other male athletes during six weeks of resistance training in a double-blind study. But most studies in recent years have had less promising results. Researchers at the University of Oklahoma gave 20 college wrestlers daily doses of either 200 mcg of chromium picolinate or a placebo (dummy pill) during 14 weeks of preseason training. At the end of the training period, the wrestlers taking the placebo had gained just as much strength and muscle as the group taking chromium.
Can chromium supplements help people with diabetes?
Possibly, but it hasn't been proven. Because chromium can boost the activity of insulin, it stands to reason that supplements might help some people with adult-onset (type 2) diabetes control their blood sugar. Indeed, several studies have consistently found that 400 mcg to 1,000 mcg (1 milligram) of chromium picolinate each day can decrease fasting blood sugar levels, lower blood cholesterol, and improve other symptoms of diabetes. However many of these studies were conducted years ago exclusively with Asian participants. Some researchers contend Asian diets typically contain less chromium than western ones, making the results of these studies appear more dramatic. More recent studies confirm these researchers reservations. A 2006 study among obese westerners with type 2 diabetes published in the American Diabetes Association journal, Diabetes Care, found no benefit in taking chromium supplements. Anderson points out that chromium is a nutrient and not a drug, which means it can only help people who are not getting enough of the mineral in their diets.
Are chromium supplements dangerous?
By most accounts, chromium supplements are safe. Anderson and colleagues have given rats the equivalent of several thousand times the daily requirement of chromium and have never seen any toxic effects. However, there have been reports of impaired thinking and uncoordinated movements in people taking as little as 200 to 400 mcg a day.
There is one note of caution, however: While the Institute of Medicine has no upper limit on daily chromium consumption, it does stipulate that chromium should be ingested via food sources only.
How can I get enough chromium in my diet?
Chromium is found in almost all foods. According to the Institute of Medicine, adults should consume between 25 and 35 mcg of chromium every day. (Women who are breastfeeding should get 45 mcg a day.) To get enough chromium, eat a diet that's rich in potassium, phosphorous, vitamin B6, protein, and carbohydrates; good food sources include whole grains and cereals, brewer's yeast, condiments such as black pepper and thyme, and meat products and cheeses. You should also stay away from highly processed foods packed with refined sugars. Not only are these foods low in chromium, they can actually block absorption of the mineral.
American Diabetes Association. Chromium Has No Benefits for Obese Westerners With Poorly Controlled Type 2 Diabetes. March 2006.
Institute of Medicine of the National Academies. Summary Tables: Dietary Reference Intakes. 2005.
National Institutes of Health. Office of Dietary Supplements. Chromium Fact Sheet. August 2005.
Walker LS, et al. Chromium picolinate effects on body composition and muscular performance in wrestlers. Med Sci Sports Exerc 1998 Dec;30(12):1730-7.
Kreider RB. Dietary supplements and the promotion of muscle growth with resistance exercise. Sports Med 1999 Feb;27(2):97-110.
Anderson RA. Effects of chromium on body composition and weight loss. Nutrition Reviews Vol. 56, No. 9, September 1998: 266-270.