VEGETABLE PROTEIN AND ATHEROSCLEROSIS

A number of studies purport to demonstrate that animal protein (usually casein) is more cholesteremic and atherogenic than vegetable protein (usually soy protein). These findings are generally true, but the effect of any single dietary component may be influenced by any other one. Thus, when the carbohydrate is dextrose, casein is more cholesteremic in rabbits than is soy protein, but when the carbohydrate is raw potato starch, the two proteins are equivalent. Similarly, a casein-cellulose diet is more cholesteremic and atherogenic for rabbits than is one containing soy protein and cellulose. Substitution of alfalfa for cellulose renders the two proteins virtually the same. In man, too, vegetable protein appears to be less cholesteremic than animal protein. The difference persists even in the face of saturated fat. In seeking a mechanism to explain the differences in atherogenicity, we have hypothesized that a high ratio of lysine to arginine may be important. The lysine/arginine ratio of casein is 2.0 and that of soy protein is 0.90. Addition of enough lysine to a soy protein diet to raise the lysine/arginine ratio to 2.0 also increases the atherogenicity of that diet. © 1979 The American Oil Chemists' Society.