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 -- and studies suggest the average American falls short -- 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.

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. The conflicting results have led to controversy and confusion, 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 in 1989 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.

The studies of chromium and weight loss are equally conflicting. Researchers at the Health and Medical Research Foundation in San Antonio, Texas, reported in 1996 that daily supplements of either 200 mcg or 400 mcg of chromium helped overweight patients lose an extra 4.2 pounds of fat over 72 days. But Richard A. Anderson, lead scientist at the U.S. Department of Agriculture's Beltsville Human Nutrition Research Center, says he has never detected any effect of chromium supplements on body weight in 20 years of study. Anderson summed up his opinion of the supplements in the September 1998, issue of the journal Nutrition Reviews: "Chromium is only a small part of the puzzle in weight loss and body composition, and its effects, if present, will be small compared with those of exercise and a well-balanced diet."

Possibly. 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 six-month, 2006 study published in the American Diabetes Association journal, Diabetes Care, found no benefit in taking chromium supplements to obese westerners with Type 2 diabetes. 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.

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. To be safe, take chromium orally in amounts of no more than 50 to 200 mcg a day.

There is one note of caution: Researchers at the University of Alabama in Tuscaloosa reported at the 1999 meeting of the American Chemical Society that chromium picolinate had apparently damaged DNA in living cells in test tube studies. In a report in the Journal of the American Medical Association, the researchers speculated that the supplements could potentially increase the risk of cancer. The researchers also said the cancer risk couldn't be fully understood without long-term studies. And 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.

Chromium is found in almost all foods, but Americans apparently may not get enough. 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.) In 1985, Anderson and colleagues studied the diets of 32 adults and found that not a single one of them averaged as much as 50 mcg in 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.

-- Chris Woolston, M.S., is a health and medical writer with a master's degree in biology. He is a contributing editor at Consumer Health Interactive, and was the staff writer at Hippocrates, a magazine for physicians. He has also covered science issues for Time Inc. Health, WebMD, and the Chronicle of Higher Education. His reporting on occupational health earned him an award from the northern California Society of Professional Journalists.

References

First published January 26, 2000
Last updated December 14, 2007
Copyright © 2000 Consumer Health Interactive

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