Soy Protein Reduces Serum Cholesterol by Both Intrinsic and Food Displacement Mechanisms

The apparently smaller LDL cholesterol (LDL-C)-lowering effect of soy in recent studies has prompted the U S FDA to reexamine the heart health claim previously allowed for soy products We therefore attempted to estimate the intrinsic and extrinsic (displacement) potential of soy in reducing LDL-C to determine whether the heart health claim for soy continues to be justified The intrinsic effect of soy was derived from a meta-analysis using soy studies (20-133 g/d soy protein) included in the recent AHA Soy Advisory The extrinsic effect of soy in displacing foods higher in saturated fat and cholesterol was estimated using predictive equations for LDL C and NHANES III population survey data with the substitution of 13-58 g/d soy protein for animal protein foods The meta-analysis of the AHA Soy Advisory data gave a mean LDL C reduction of 0 17 mmol/L (n = 22 P < 0 00011 or 4 3% for soy which was confirmed in 11 studies reporting balanced macronutrient profiles The estimated displacement value of soy (13-58 g/d) using NHANES III population survey data was a 3 6-6 0% reduction in LDL C due to displacement of saturated fats and cholesterol from animal foods The LDL C reduction attributable to the combined intrinsic and extrinsic effects of soy protein foods ranged from 7 9 to 10 3% Thus soy remains one of a few food components that reduces serum cholesterol (> 4%) when added to the diet J Nutr 140 2302S-2311S 2010