Coronary heart disease (CHD) includes a number of risk factors. One of the most important is elevated blood pressure. A recent study presented by researchers from Wake Forest University found that the systolic blood pressure (top number) of people consuming the most soy isoflavones was 5 points (mm Hg) lower than that of people who consumed diets low in isoflavones.1 The effects were especially pronounced in African Americans. Isoflavones are naturally-occurring plant compounds that are found in especially high amounts in soybeans and traditional soyfoods such as soymilk.
Soyfoods can make important contributions to heart-healthy diets. They provide high-quality protein and, in contrast to more traditional sources of protein in Western diets, they are low in saturated fat, high in polyunsaturated fat, and cholesterol free.2,3 When soyfoods are substituted for animal products, blood cholesterol levels may be reduced.4 In addition, soy protein directly lowers LDL blood cholesterol. This benefit of soy protein was formally recognized by the U.S. Food and Drug Administration in 1999 when it approved a health claim for soyfoods and coronary heart disease.5
The results from the Wake Forest study by itself do not allow definitive conclusions to be drawn. However, they are consistent with previously published research. To this point, a recently published statistical analysis that included 27 clinical (human intervention) studies found that on average, soy lowered blood pressure about 2 ½ points.6
More research into the effects of soy on blood pressure is needed. Given all the advantages of soyfoods, people concerned about reducing their risk of heart disease may want to consider adding soyfoods to their diets.
References
1. Richardson S, Smith C, Burke L, Xia Z, Shikany JM, Steffen L, Rodriguez CJ. Dietary isoflavone intake is associated with lower systolic blood pressure: the Coronary Artery Risk Development in Young Adults (CARDIA) Study (Abstract). Am College Cardiol Annual Meeting. 2012.
2. Hughes GJ, Ryan DJ, Mukherjea R, Schasteen CS. Protein digestibility-corrected amino acid scores (PDCAAS) for soy protein isolates and concentrate: Criteria for evaluation. J Agric Food Chem. 2011; 59: 12707-12.
3. 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: 11174-85.
4. Jenkins DJ, Mirrahimi A, Srichaikul K, Berryman CE, Wang L, Carleton A, Abdulnour S, Sievenpiper JL, Kendall CW, et al. Soy protein reduces serum cholesterol by both intrinsic and food displacement mechanisms. J Nutr. 2010; 140: 2302S-2311S.
5. Food labeling: health claims; soy protein and coronary heart disease. Food and Drug Administration, HHS. Final rule. Fed Regist. 1999; 64: 57700-33.
6. Dong JY, Tong X, Wu ZW, Xun PC, He K, Qin LQ. Effect of soya protein on blood pressure: a meta-analysis of randomised controlled trials. Br J Nutr. 2011; 106: 317-26.
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HEART HEALTH
Soy & Blood Pressure
Coronary heart disease (CHD) includes a number of risk factors. One of the most important is elevated blood pressure. A recent study presented by researchers from Wake Forest University found that the systolic blood pressure (top number) of people consuming the most soy isoflavones was 5 points (mm Hg) lower than that of people who consumed diets low in isoflavones.1 The effects were especially pronounced in African Americans. Isoflavones are naturally-occurring plant compounds that are found in especially high amounts in soybeans and traditional soyfoods such as soymilk.
Read more