The influence of copper and zinc on the occurrence of ischemic heart disease.

The zinc/copper hypothesis, which invokes relative or absolute deficiency of copper in the etiology of ischemic heart disease, was described. The belief that calcium (and, perhaps, magnesium) is a substance in hard water which protects against ischemic heart disease by altering copper and zinc metabolism was presented. The amounts of copper and zinc in drinking water usually are too small to produce important increases in the amounts of these elements in diets. Occasionally tap water high in copper may be an important supplement to a diet low in copper.