DIETARY ZINC-DEFICIENCY AND FATTY-ACID METABOLISM RATS

Several clinical features of zinc deficiency in rats are similar to th ose of essential fatty acid deficiency suggesting a role of zinc in fa tty acid metabolism. In order to find out the role of zinc in fatty ac id metabolism, several zinc deficiency studies in rats have been carri ed out. The results of those studies are reviewed in this paper with r espect to the effects of zinc deficiency on the desaturation of fatty acids, the incorporation of polyunsaturated fatty acids into tissue li pids and the fatty acid composition of erythrocyte membranes. Zinc def iciency experiments indicate that zinc plays a role in Delta 5 and Del ta 6 desaturation although there are some reports that did not support such a function of zinc. The effects of zinc deficiency on Delta 9 de saturation are contradictory. Some results suggested that zinc deficie ncy increased Delta 9 desaturation, while others suggested reduced Del ta 9 desaturation. Phospholipids of zinc deficient rats contained high er amounts of (n-3) polyunsaturated fatty acids and lower amounts of ( n-6) polyunsaturated fatty acids, suggesting that zinc deficiency infl uences the incorporation of polyunsaturated fatty acids into phospholi pids. In contrast, zinc deficiency had only slight effects on the fatt y acid composition of erythrocyte membranes. Consequences of changes i n fatty acid metabolism by zinc deficiency may include synthesis of ei cosanoids and properties of membranes.