Can Chromium Supplements Cause Cancer?

Q: I have read that chromium picolinate is dangerous and can even cause cancer. Is this true?
-S.M.

A: Hi S.M.,

Most of the concerns about the safety of chromium come from two insignificant test-tube studies, the first of which was conducted back in 1996. It showed that exposing isolated hamster cells to extremely high concentrations of chromium (3,000 times higher than the amount supplement takers are exposed to) may cause chromosomal damage in these isolated cells. This kind of a test-tube experiment — called an in-vitro experiment — tells us nothing about what actually happens to chromium picolinate inside the body.

A subsequent studied revealed that chromium picolinate interacts with vitamin C — again, in a test tube, not in the human body — to produce chromium II. In turn, chromium II can interact with oxygen to generate free radicals that may potentially cause mutations in DNA. Sound scary? Well, in fact, biochemists know that these same interactions occur with numerous other minerals commonly found in food and supplements — such as iron, manganese, and copper — and no one is crying “Fire!” about these supplements.

The truth is that numerous animal and human studies, which are much more reliable (though less sensational) than the lab studies described above, have demonstrated that chromium is extremely safe. In one toxicity study, rats fed 100 mg/kg of chromium picolinate daily (equal to several thousand 200-mcg tablets for a 150-pound human) showed no signs of toxicity. Likewise, the U.S. Department of Agriculture has found no toxicity or adverse effects with high doses of chromium.

The Ames test, commonly used to identify potential cancer-causing substances, gave chromium the thumbs up, as do standard medical reference books. According to Modern Nutrition in Health and Disease (Lippincott Williams & Wilkins), the worst that can be said is that, at high doses, “chromium…acts as a gastric irritant rather than as a toxic element.”

Far from being toxic, chromium picolinate is a valuable tool in the treatment of diabetes, as it helps lower blood glucose levels and correct insulin resistance, a condition in which the body produces enough insulin but the cells are unresponsive to it. Given that insulin resistance is a known risk factor for certain types of cancer, supplementing with chromium picolinate may actually decrease the risk of cancer. I recommend that the general population take 200-400 mcg chromium picolinate per day and people with diabetes up their daily dose to 1,000 mcg, in divided doses.

Yours in good health,
Dr. Whitaker