ABSTRACT

Protein of animal origin is more cholesterolemic and atherogenic than protein of plant origin. The accepted mechanism underlying this difference is that plant protein inhibits lipid absorption and enhances degradation and excretion. In a study of protein-fiber interactions, author compared the effects of semipurified, cholesterol-free diets containing casein or soy protein and either cellulose, alfalfa, or wheat straw. The standard cholesterol-free, semipurified diet which is atherogenic for rabbits contains cellulose as the fiber. When the diet contained cellulose, soy protein was significantly less cholesterolemic and less atherogenic than casein. The effect on cholesterolemia held when the fiber was wheat straw and the soy diet was still less atherogenic than that containing casein. The two proteins yielded virtually identical results when the fiber was alfalfa. The results point up the importance of considering dietary interaction rather than considering a single nutrient when assessing diet and atherosclerosis.