Decreased High Density Lipoprotein Cholesterol and Apoprotein A-i in Plasma and Ultrastructural Pathology in Cardiac Muscle of Young Pigs Fed a Diet High in Zinc

People who supplement their diets with extra zinc usually have potentially harmful changes in lipoprotein metabolism. Because zinc can interfere with copper metabolism and copper deficiency has produced similar changes in lipid metabolism in animals and people, the hypothesis that lipid alterations from high zinc intakes are accompanied by changes in copper metabolism was tested. Progenies of swine fed a high zinc (5000 mgkg diet) or normal zinc (150 mgkg diet) diet during pregnancy and lactation were weaned to practical diets of natural products containing similar amounts of zinc. Concentrations of apoprotein A-I @<0.05) and high density lipoprotein cholesterol (p<0.004) were decreased and the agerelated increase in the latter was delayed @=0.0001) by high zinc intake. Copper in blood plasma @=0.0008), heart @<0.004) and liver @<0.06) were decreased by high zinc intake which increased plasma @=0.001) and liver zinc @=0.0001). Quantitative electron microscopy revealed that hearts of young pigs fed high zinc had less myofibrillar volume and a higher volume ratio of mitochondria to myofibrils. Anatomical changes, lipid concentrations and copper concentrations were consonant with the induction of mild copper deficiency by high intakes of zinc. The potentially hazardous changes in lipid metabolism usually found in people who take zinc supplements probably are the result of an induction of mild copper deficiency.