Elevated cholesterol is one of a number of risk factors in heart disease. Diet and lifestyle can play a role in this component. Along with exercise, reducing intake of saturated fat has been shown to help improve blood cholesterol levels. This includes consuming a plant-based diet rich in fruits, vegetables, whole grains, seeds, nuts and legumes such as soy.
The cholesterol-lowering effects of soy protein have been demonstrated in clinical studies for more than 45 years.1 In 1999, the US Food and Drug Administration formally recognized the ability of soyfoods to lower cholesterol by approving a health claim for soyfoods and coronary heart disease.2 Foods that provide at least 6.25 grams of soy protein per serving may be eligible for the claim. This figure was established by the FDA, as 25 grams per day was considered the threshold intake needed for cholesterol reduction. Four servings per day of soyfoods were considered a reasonable intake for this threshold. A typical serving of soy includes ½ cup edamame, 3 ounces of tofu, or 1 cup of soymilk.
Evidence reveals consuming this amount of soy protein can lower cholesterol by about 4 percent.3,4,5 This level of reduction can be beneficial, particularly when incorporating soyfoods in a diet that is heart-protective overall. When the effects of healthy fats (poly and mono-unsaturated) along with the effects of soy protein are taken into consideration, it’s possible that replacing other sources of protein with soy could lower cholesterol by as much as 8 percent.6 Over time, this could reduce heart disease risk by as much as 16 percent.7,8
The way in which soy protein lowers cholesterol isn’t well understood, however one theory is that the protein is digested to form peptides that promote degradation of cholesterol in the liver.9,10 Additionally, soybeans are rich in healthful polyunsaturated fat. When they replace meat and cheese in diets, they automatically lower the saturated fat content of diets.11
While no single food is powerful enough to markedly prevent heart disease, a combination of healthy foods and an active lifestyle can have a significant effect. Using a low-saturated fat diet high in fiber, fruits, vegetables, plant sterols, nuts, and soyfoods, Canadian researchers were able to reduce cholesterol by 30 percent.12
Consider adding soy to your diet, and you may be able to reap the benefits as well!
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2. Food Labeling: Health Claims; Soy Protein and Coronary Heart Disease. In: Federal Register: (Volume 64, Number 206)]; 1999. p. 57699-57733.
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4. Harland JI, Haffner TA. Systematic review, meta-analysis and regression of randomised controlled trials reporting an association between an intake of circa 25 g soya protein per day and blood cholesterol. Atherosclerosis 2008;200(1):13-27.
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6. Jenkins DJ, Mirrahimi A, Srichaikul K, Berryman CE, Wang L, Carleton A, et al. Soy protein reduces serum cholesterol by both intrinsic and food displacement mechanisms. J Nutr 2010.
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9. Cho SJ, Juillerat MA, Lee CH. Cholesterol lowering mechanism of soybean protein hydrolysate. J Agric Food Chem 2007;55(26):10599-604.
10. Manzoni C, Duranti M, Eberini I, Scharnag H, Marz W, Castiglioni S, et al. Subcellular Localization of Soybean 7S Globulin in HepG2 Cells and LDL Receptor Up-Regulation by Its alpha’ Constituent Subunit. J Nutr 2003;133(7):2149-55.
11. Slavin M, Kenworthy W, Yu LL. Antioxidant properties, phytochemical composition, and antiproliferative activity of Maryland-grown soybeans with colored seed coats. J Agric Food Chem 2009;57(23):11174-85.
12. Jenkins DJ, Kendall CW, Faulkner D, et al. A dietary portfolio approach to cholesterol reduction: combined effects of plant sterols, vegetable proteins, and viscous fibers in hypercholesterolemia. Metabolism 2002;51:1596-604.