Atherogenicity of animal and vegetable protein

In general, protein of animal origin is more cholesterolemic and atherogenic than plant protein. The addition of single amino acids to the protein can influence cholesterolemia and atherogenicity, by either increasing or decreasing these conditions. The lysine to arginine ratio, which is higher in animal than in plant proteins, may be a factor in cholesterolemia. The results may be explained in part by the findings that lipid absorption is elevated in rabbits or rats fed animal proteins as is turnover time. Animals fed soy protein excrete more neutral and acidic steroids, and have increased activity of hepatic HMG CoA reductase and cholesterol 7 alpha-hydroxylase. Animal protein may exert its hypercholesterolemic effect by mechanisms which include increased absorption of cholesterol and decreased turnover.