The Chromium Questions

Ads for chromium supplements commonly suggest the supplement enhances weight loss, builds muscle and controls blood sugar. Yet how much of these claims is true? Current research about the effects of chromium is helping us understand the effects of chromium and chromium supplements.

Chromium is a mineral that works with the body’s insulin to control our blood sugar. Outright chromium deficiency can lead to high levels of insulin and sugar in the blood, characteristics of diabetes, but this is uncommon. Because chromium is in many different foods, chromium deficiency is rare in the United States. It has been found only in atypical populations, such as people given long-term IV nutrition that did not include chromium. (Now, chromium is routinely added to IV solutions.)

Many studies have looked at whether higher amounts of chromium in the form of supplements can improve insulin function. According to a 2002 review of 15 well-controlled studies, chromium supplements had no effect in healthy or pre-diabetic subjects. The supplements also showed no significant effect in diabetics among Western populations, where chromium deficiency is uncommon.

In 2005, the Food and Drug Administration (FDA) approved a qualified health claim that a common supplement form of chromium, chromium picolinate, may reduce the risk of insulin resistance. A qualified health claim is based on credible but limited evidence. In the case of chromium, the qualified claim is based on one relatively small study. The FDA concludes that a relationship between chromium picolinate and either insulin resistance or type 2 diabetes is highly uncertain. Also, the American Diabetes Association says the research on chromium and insulin function is not yet conclusive enough to merit supplements.

Claims that chromium supplements can help people lose body fat or increase muscle mass have been largely disproved by well-controlled studies, although a variety of products continue to make such claims.

For those who choose to take chromium supplements, no known serious risks are linked to intake well beyond current recommendations, so the Institute of Medicine has not established a safe upper limit. However, large amounts may interact with medications. Some laboratory studies raise concerns that chromium picolinate supplements could increase DNA damage, although this has not been seen in living organisms.

The Institute of Medicine says that most American adults meet the recommended levels of 20 to 25 micrograms (mcg) per day in women and 30 to 35 mcg daily in men. Chromium content of food varies widely, and it’s distributed in small amounts in many different foods. Good sources include seafood, whole grains, bran cereals, poultry and meat. Vegetables and fruits vary, though broccoli, tomatoes, mushrooms and pears are reported as rich sources. High-sugar foods are low in chromium and also tend to increase loss of chromium in the urine.

People facing abnormal blood sugar levels who want to see if adding a chromium supplement will help should do so only if their doctor knows and is ready to follow up with needed monitoring. For most of us, research currently offers much stronger support for the impact we can make on blood sugar and weight control with daily physical activity, balanced eating and portion control.

Find more from Karen Collins.

Karen Collins, D.C.N., M.S., R.D., serves as the nutrition advisor to the American Institute for Cancer Research (AICR). Karen writes two syndicated weekly columns, "Nutrition Notes" and "Nutrition-Wise," distributed by AICR. Karen was an expert reviewer for AICR's landmark international report, "Diet, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective," which provides recommendations based on an examination of more than 7,000 research studies by a panel of internationally renowned scientists. (Read her full bio.)