Nickel has been considered as a possibly essential trace mineral for several decades. We have a total of about 10 mg. in our body, but we still do not know exactly what it does. Most of the nutritional research on nickel has been done with chicks and rats. It is an essential nutrient for these animals, and they suffer considerable problems with nickel deficiency.

Source: Elson M. Haas M.D. (Excerpted from Staying Healthy with Nutrition: The Complete Guide to Diet and Nutritional Medicine)