Zinc competes for absorption with copper and inhibits copper absorption. Copper deficiency can result in anemia, lower levels of HDL (“good”) cholesterol, neurological disorders, and cardiac arrhythmias. Copper intake should be increased if zinc supplementation continues for more than a few days (except for people with Wilson’s disease). Some sources recommend a 10:1 ratio of zinc to copper. Evidence suggests that no more that 2 mg of copper per day is needed to prevent zinc-induced copper deficiency. Many zinc supplements include copper in the formulation to prevent zinc-induced copper deficiency. Zinc-induced copper deficiency has been reported to cause reversible anemia and suppression of bone marrow. In addition, there are case reports of neurologic abnormalities due to copper deficiency occurring in people who had been using large amounts of certain widely available denture creams that contained high concentrations of zinc.
Refrences
- Dawson EB, Albers J, McGanity WJ. Serum zinc changes due to iron supplementation in teen-age pregnancy. Am J Clin Nutr 1990;50:848-52.
- Broun ER. Greist A, Tricot G, Hoffman R. Excessive zinc ingestion. A reversible cause of sideroblastic anemia and bone marrow depression. JAMA 1990;264:1441-3.
- Reiser S, Powell A, Yang CY, Canary JJ. Effect of copper intake on blood cholesterol and its lipoprotein distribution in men. Nutr Rep Int 1987;36:641-9.
- Sandstead HH. Requirements and toxicity of essential trace elements, illustrated by zinc and copper. Am J Clin Nutr 1995;61(suppl):621S-24S [review].
- Fischer PWF, Giroux A, Labbe MR. Effect of zinc supplementation on copper status in adult man. Am J Clin Nutr 1984;40:743-6.
- Nations SP, Boyer PJ, Love LA, et al. Denture cream. An unusual source of excess zinc, leading to hypocupremia and neurologic disease. Neurology 2008;71:639-43.