Publix GreenWise Market Magazine - May 2008
This mineral enhances the action of insulin. Can it also help manage diabetes?
What it is
Classified as a trace mineral, chromium is something the body needs only in minute quantities, but don't underestimate its importance. It not only plays an essential role in the metabolism of proteins and fats but also affects levels of blood glucose (sugar) by helping insulin move glucose into the body's cells. For that reason, chromium has been the subject of much speculation about whether it might help in the management or even the prevention of type 2 diabetes.
Where to get it
Dietary sources of chromium include broccoli, grape juice, whole grains and red wine, but most of these foods contain only small quantities, generally just a few micrograms (mcg) per serving. Vitamin C (from fruits and vegetables as well as their juices) and niacin (from fish, meat, poultry and grains) help to enhance chromium absorption.
Chromium supplements are available in several forms, including chromium picolinate, chromium chloride, chromium nicotinate, chromium citrate and high-chromium yeast. It's not yet clear which is the best. A typical dose is 50 mcg to 200 mcg a day. If you have diabetes, talk to your doctor or pharmacist before starting chromium supplements, since they may interact with certain medications, including insulin.
Evidence so far
An analysis of 15 randomized controlled trials (American Journal of Clinical Nutrition, July 2002) concluded that chromium had no effect on insulin and glucose levels in healthy individuals. For people who already had prediabetes or diabetes, results were inconclusive. However, a more recent small study of 37 people with type 2 diabetes (Diabetes Care, August 2006) found that chromium picolinate supplements improved glucose control, insulin sensitivity and weight management.
The jury's still out
John Buse, M.D., president for medicine and science at the American Diabetes Association, says some of the studies that have shown chromium to be beneficial may have involved groups of people who were chromium-deficient to begin with. Reports of chromium deficiency in the United States are rare. Some research suggests that older adults are more likely than younger ones to have depleted stores of chromium. That's hard to know for sure, though, since it's difficult to measure chromium status.
Further clouding the picture is the fact that previous studies used various formulations of chromium and different dosing levels, says Rebecca B. Costello, Ph.D., director of grants and extramural activities at the Office of Dietary Supplements of the National Institutes of Health. "And most of the studies were short-term, six months or less,' she says. Costello is encouraged by ongoing studies that permit moment-by-moment monitoring of the insulin response to a glucose challenge. "Those more sophisticated, sensitive studies will give us a better idea of how chromium works."
The bottom line
Although the American Diabetes Association's current stance is that the benefit of chromium supplements for people with diabetes has not been clearly shown, Buse welcomes further research on the subject. In the meantime, for those considering a chromium supplement, he advises careful monitoring of blood glucose to make sure the supplement is helping. Chromium supplements should always be used in addition to, not in place of, conventional medical treatment.