Chromium

Chromium is a common ingredient in weight loss formulas. It is a trace mineral essential for the body in small amounts. Its key physiological role appears to be regulation of carbohydrate metabolism. In particular, chromium appears to act as a co-factor to insulin to allow the glucose in the blood to enter cells.

As an insulin action enhancer, chromium has been studied as an agent to help prevent or treat diabetes. So far, the evidence indicated a modest positive effect of chromium towards reducing insulin resistance and normalizing carbohydrate tolerance. The effects are likely to be greater in people with chromium deficiency. While severe chromium deficiency is rare, mild chromium deficiency is not uncommon in general population.

Since insulin resistance seem to be among the factors affecting weight control, chromium has been touted as a weight loss aid. Unfortunately, most studies failed to find any significant effect of chromium supplements on weight loss. However, even though chromium does not seem to affect body weight, the is some evidence that it may modestly improve body composition, i.e. reduce body fat and increase lean tissue.

While there shouldn't be any illusions of chromium promoting significant weight loss, chromium supplement may be warranted in overweight people. First, many overweight people have impaired carbohydrate tolerance and most are at risk of developing it. Second, even modest improvement in body composition may have health benefits in overweight people.

As opposed to most vitamins, trace minerals tend to have a rather narrow therapeutic window (the dose range where they are both beneficial and safe). Chromium doses between 50 mcg and 200 mcg per day are considered safe by most experts. Studies of chromium supplements used doses from 200 mcg to 1,000 mcg per day, apparently without major side effects. However, most studies were relatively short term and may have missed potential toxicity at the high end of the range. There are isolated reports in medical literature of chromium toxicity after allegedly taking doses as low as 600 mcg for as little as several weeks. Until chronic chromium toxicity is better researched, most experts recommend against taking chromium doses above 200 mcg per day without medical supervision.

Not all chromium supplements are created equal. Some are absorbed much better than others. Chromium picolinate and possibly chromium polynicotinate offer that greatest and most reliable absorption. Other common forms of supplemental chromium, such as chromium chloride or yeast-bound chromium are absorbed poorly and in some people may be entirely ineffective.

See also the index of studies related to chromium.