Soy protein, soybean isoflavones and coronary heart disease risk: where do we stand?

The cholesterol-lowering effects of soy protein have been extensively investigated during the past 40 years. In 1999, the US FDA approved a health claim for soy protein and coronary heart disease based on the hypocholesterolemic effects of soy protein. However, results from recent meta-analyses indicate these effects are more modest than initially reported. Nevertheless, soyfoods can help to shift the mean cholesterol level of the population downward. When substituted for other common dietary sources of protein, soyfoods will further aid this downward shift because they provide high-quality protein but are low in saturated fat and devoid of cholesterol. In addition, intriguing but still speculative evidence suggests that soyfoods, probably because they contain isoflavones, may have lipid-independent coronary benefits, such as enhancing vascular reactivity. The combined cardioprotective attributes of soyfoods warrant their having a larger role in Western diets.