Dietary Fat and Protein and Serum Cholesterol

Abstract

Adult swine were fed either a human-type diet of mixed foods or a purified diet with changes in the amount and type of fat or the amount of protein. In both types of diet, fat caused the serum cholesterol to rise with the greatest increase resulting from the most saturated fat. The human-type diet consistently gave higher serum cholesterol values, but the response to different fats paralleled the results obtained with the purified diet. With the purified diet, lowering the protein to a level of approximately 5% did not affect the level of serum cholesterol. However, with the large sows (300 to 500 pounds) that were used, this protein level gave no indication of depletion of serum proteins. When all protein was removed from the diet and the swine were continued on this regimen for more than 4 weeks some elevation of serum cholesterol was observed. Swine receiving a corn oil diet had lipoprotein values by electrophoretic analysis in which the α fraction was consistently lower than the β. This is the same direction as ratios that have been found in man.