Experimental Studies on the Interrelationships of Nutrition and Physical Exercise

Abstract

The combined effects of the quality of dietary fats, vitamin E (V. E) supplementation and physical exercise on the cholesterol contents and fatty acid composition of both in serum and tissue lipids, and also on urinary 17-ketosteroid (17-KS) excretion were investigated. Male rats at 40 days of age were allocated to either a fat-free diet or diets containing 20% of safflower oil or beef tallow with and without an additional supply of V. E (330mg/kg diet).Ten rats from each dietary group were housed in cages equipped with a revolving wheel inside and allowed voluntary exercise throughout the entire period. After 2 months on the experimental regimen, a significant drop in the serum cholesterol and a slight increased in liver cholesterol were observed among the animals given safflower oil. V. E supplementation exerted a reverse effect against safflower oil on lowering the serum cholesterol. The rats fed on beef tallow showed the least deposition of cholesterol in liver, followed by those of a fat-free group. Prolonged deprivation of fat from diets was accompanied by a high cholesterol content in the adrenals. Exercise had no appreciable effect on serum cholesterol levels. Dietary fat had a pronounced effect on the fatty acid composition of lipids in serum, liver, adrenal and perirenal fat depot. A marked reduction in linoleate and arachidonate and a compensatory increase in C20-trienes in the liver lipid of rats given a fat-free diet were seen. Both exercise and V. E had no effects on fatty acid composition. Prolonged ingestion of beef tallow resulted in a small depression of urinary 17-KS excretion, but exercise and V. E exerted no further influences on the 17-KS output.