It’s been 12 years since the US Food and Drug Administration approved a health claim for soyfoods and coronary heart disease based on the cholesterol-lowering effects of soy protein. The research that first brought these benefits of soy protein to the attention of the medical and scientific communities was conducted by James Anderson, MD, from the University of Kentucky.
In 1995, Dr. Anderson and his colleagues published a meta- analysis of 34 different clinical trials which showed that soy protein lowered LDL-cholesterol by nearly 13 percent. This effect was greater than what has been shown for any other single food, and was comparable to the results achieved from the available cholesterol-lowering drugs. Despite these impressive results, findings from individual studies have been inconsistent, raising questions about the true magnitude of the cholesterol-lowering effects of soyfoods. Now, 16 years later, those questions have been answered.
Dr. Anderson has confirmed his initial findings about the effects of soy protein in a new analysis of the literature, which included 20 studies published after his 1995 analysis. He and colleague Heather Bush, PhD found that, among subjects consuming soy protein, LDL-cholesterol was lowered by 5.5 percent compared to those subjects who consumed a non-soy control protein (usually casein from milk). The effect was much greater in subjects who had elevated cholesterol to begin with. In addition, soy protein raised good HDL-cholesterol by about 3 percent and lowered triglycerides by approximately 11 percent. Although the cholesterol-lowering effects of soy protein were found to be less robust than initially reported, Drs. Anderson and Bush estimated that the collective effects of soy protein on LDL-cholesterol, HDL-cholesterol, and triglycerides would lower heart disease risk by 12 to 20 percent. Soyfoods are likely to have a further positive impact on heart disease risk since they are also low in saturated fat and high in healthy unsaturated fats. Soyfoods like tofu, tempeh, soymilk and veggie meats can play an important role in heart healthy diets.
Anderson JW, Bush HM. Soy Protein Effects on Serum Lipoproteins: A Quality Assessment and Meta-Analysis of Randomized, Controlled Studies. J. Am. Coll. Nutr. 2011; 30: 79-91.