The selective lipid-lowering effect of vegetarianism on low density lipoproteins in a cross-over experiment.

In a cross-over experiment the effect of short-term vegetarianism on serum lipids, lipoproteins and apoproteins was studied. The experimental diet was free of animal products, with the exception of skim milk, and consequently low in saturated fat and cholesterol. Fifteen free-living individuals were randomly assigned to 3-week periods on either the experimental diet or a control diet which closely approximated the usual intake in the U.S.A. Significant reductions in total cholesterol (12.5%), low density lipoprotein cholesterol (14.7%), and apo B (13.2%) were observed, accompanied by a non-significant decrease in high density lipoprotein cholesterol (10%), apo A-I (3%) and a non-significant increase in apo-II (4%). These data suggest that a fat-modified diet low in total fat, saturated fat and cholesterol, and moderate (not high) in polyunsaturated fat may not lower HDL-C or its apoproteins as much as a diet high in polyunsaturated fat, while having similar effects on LDL-C, and would therefore be preferable as the basis for primary prevention of atherosclerosis.