Q. What are the harmful side effects, if any, of chromium when taken as a dietary supplement?
A. Chromium is one of several minerals that was once thought to be important for glucose metabolism, based on research in rats that showed that chromium binds with insulin to enhance its activity. However, this effect has not been reproduced in humans -- and, in fact, the only reported cases of chromium deficiency are in patients fed exclusively on intravenous nutrition for long periods of time. The recommended intake for chromium is 1 microgram per day; the average intake for a typical American diet is 20 to 50 micrograms per day, and the safety margin is 50 to 200 micrograms per day.
If you are taking a supplement, look at the amount of micrograms and keep it under 50 mcg per day. Remember, supplements are similar to medications and you should really only take them for a specific purpose. Otherwise, get most of your vitamins and minerals from a healthy diet.