Chromium is an essential trace mineral found in a variety of foods, including whole grains, cereals, spices (such as black pepper), broccoli, mushrooms, cheese, seafood and meat. In the body, it plays a role in metabolizing fats and carbohydrates and controlling blood levels of sugar.
The body has a hard time absorbing chromium supplements in mineral form; it is absorbed more easily when it's bound to another molecule. Chromium niacin, sometimes called niacin-bound chromium, is one form of so-called bioavailable chromium sold as a supplement: Another commonly sold form is chromium picolinate.
Uses: Chromium niacin (also known as chromium polynicotinate) and chromium picolinate are often taken for diabetes, weight loss, body building or, sometimes, to prevent heart disease.
Dose: The Institute of Medicine recommends a daily chromium intake of 25 to 45 micrograms. Most people get about 25 micrograms from food: Nutrition experts think that's sufficient (breastfeeding moms may need 45 micrograms). Supplement manufacturers recommend doses of 50 to 200 micrograms a day.
Precautions: The long-term safety of taking high doses of chromium is unknown. Chromium niacin appears safe in manufacturer-recommended doses but chromium picolinate has been linked to a few cases of kidney failure and liver damage. Animal studies suggest chromium picolinate has cancer-causing potential.
Research: In lab studies, animals deprived of chromium become glucose intolerant: Their bodies fail to efficiently remove sugar from their blood. Research published in the late 1970s showed that people deprived of chromium developed diabetes-like symptoms, which were reversed following chromium supplementation.
But the supplements won't necessarily help people who aren't chromium-deprived. A 2002 review of 15 clinical trials, published in the American Journal of Clinical Nutrition, concluded that the supplement didn't improve glucose or insulin levels in people with Type 2 diabetes.
Animal tests have suggested chromium may help lower cholesterol levels and protect against heart disease. Human findings are mixed: A 2005 study published in the American Journal of Epidemiology linked low chromium levels to increased heart disease risk in men.
Dozens of studies on chromium picolinate and weight control are inconclusive: Some have reported that the supplement helps with weight loss, others that it doesn't. Chromium niacin's role in weight loss is less studied. A small clinical trial in India, published in 2004 in the journal Diabetes, Obesity and Metabolism, showed that chromium niacin, taken with hydroxycitric acid and the herb \o7Gymnema sylvestre \f7for eight weeks, decreased body weight by an average of 5% in obese subjects. More studies are needed to confirm this effect.
Dietary supplement makers are not required by the U.S. government to demonstrate that their products are safe or effective. Ask your healthcare provider for advice on selecting a brand.
-- Elena Conis