Soy protein and cardiovascular disease: A statement for healthcare professionals from the nutrition committee of the AHA

Considering the totality of research, daily consumption of ≥25 g of soy protein with its associated phytochemicals intact can improve lipid profiles in hypercholesterolemic humans. This effect was observed in clinical trials to be additional to the benefits of an NCEP Step I diet and is greater in more-hypercholesterolemic subjects. The mechanisms by which soy modulates blood cholesterol and lipoprotein levels need further research. Soy protein without the isoflavones appears to be less effective. Consuming isoflavones without soy protein does not lower cholesterol but may provide other cardiovascular benefits. The effects of using soy extracts of isoflavones as dietary supplements are largely unknown and cannot be recommended. Apparently there is a synergy among the components of intact soy protein, which provides the maximum hypocholesterolemic benefit. A variety of clinical trials have demonstrated that consuming 25 to 50 g/d of soy protein is both safe and effective in reducing LDL cholesterol by ≃4% to 8%. The beneficial effects of soy are proportionally greater in people with hypercholesterolemia. Lichtenstein⁴⁷ has noted that the judicious substitution of soy for animal protein can result in lower saturated fat and cholesterol intakes, thereby indirectly resulting in a more favorable blood cholesterol level and potentially reducing coronary heart disease risk. In conclusion, it is prudent to recommend including soy protein foods in a diet low in saturated fat and cholesterol to promote heart health.