Polyunsaturated Ruminant Fats and Cholesterol Metabolism in Man

Summary: Milk and meat fats of cattle arid sheep, in which the ratio of polyunsaturated to saturated fatty acids had been raised tenfold, were eaten by eight healthy men for 36 days. In comparison with a 40-day period during which conventional animal fat was eaten, both the plasma cholesterol and triglyceride concentrations were significantly lower. Following each dietary change, the serum cholesterol reached a new stable level after 20 days. Cholesterol balance was measured during the last 10 days of each diet by measuring cholesterol absorption, cholesterol synthesis and bile acid excretion. These parameters were similar during the steady-state period of both diets, in contrast to our previous study which showed increased sterol excretion as plasma cholesterol concentrations fell during the first 20 days of the polyunsaturated fat diet.