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Submitted to: Trace Elements in Man and Animals International Symposium
Publication Type: Proceedings Publication Acceptance Date: 5/18/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Copper is an essential nutrient that is important in maintaining a healthy heart and blood vessels. There is a need to know how much copper people need in order to make informed dietary recommendations. A series of 12 studies of the effects of diets that were low in copper in men and women, showed changes in some people when diets containing 1.0 milligram of copper or less per day were fed. About 20% of the people had an increase in the number of abnormal heartbeats and many showed changes in copper-containing proteins in blood cells when they ate less than one milligram of copper per day. These studies show that copper-containing proteins in blood cells are better for determining copper nutritional status in people than plasma copper. Also, at least 1.0 to 1.25 milligrams of copper are needed by adults to maintain good health. However, more than 2.6 milligrams of copper per day may be needed to recover from the effects of copper deficiency. Technical Abstract: Over the past decade, there have been 12 experiments reported on experimental copper deprivation, and/or interactions of copper (Cu) with other nutrients in adult humans. Cu intakes of these studies have ranged between 0.4-1.25 mg of Cu per day for periods of 36-165 days. These were alternated with or followed by intakes of 2.6 to 6.4 mg of Cu per day. Biochemical and physiological changes caused by Cu deprivation were noted in many, but not all, subjects consuming less than 1.2 mg of Cu per day. These include changes in electrocardiograms in 4 of 24 men receiving 1.02 mg of Cu per day and a high fructose diet after 77 days, 1 of 7 men fed 0.8 mg of Cu per day for 105 days, 3 of 6 men fed 0.6 mg of Cu per day for 49 days, and 3 of 13 postmenopausal women fed 0.57 mg Cu per day for 105 days. Plasma Cu was lowered with low Cu intake in only 4 of the 12 studies; it seemed to be related more to weight loss or fructose intake in two of these studies and was not as sensitive as Cu enzymes in blood cells. Erythrocyte superoxide dismutase (ESOD) and cytochrome c oxidase (CCO) in platelets or mononucleated white cells seemed to be the most sensitive indicators to changes in Cu status. Recovery from Cu deprivation, as indicated by recovery of ESOD activity was documented when 3 to 6.4 mg of Cu per day was fed for 30 days or more, but not when 2.6 mg or less was fed for up to 42 days. These studies indicate that between 1.0 and 1.25 mg of Cu/d is needed for maintenance and that 2.6 mg of Cu per day, or less, for periods of up to 42 days is not sufficient for recovery from Cu deprivation. |
