Soy Protein Helps Reduce Systolic Blood Pressure

Researchers at Columbia University (New York, NY, USA) analyzed data from the 20-year information of 589 participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study. The study, involving 5,115 African American and white Americans aged 18-30 years old, was created to examine the development and determinants of cardiovascular disease. The researchers evaluated the relation between daily isoflavone intake and SBP after dividing patients across quartiles, according to self-reported isoflavone intake.

The researchers found that compared to those in the lowest quartile, consuming less than 0.33 mg of isoflavones per day, those reporting the highest level of isoflavone intake correlated with a 5.52 mm Hg reduction in SBP. Even after controlling for age, sex, body mass index (BMI), smoking, alcohol, physical activity, and total caloric intake, the relationship between daily isoflavones and lower systolic blood pressure remained present. The study was presented at the American College of Cardiology (ACC) 61st annual scientific session, held during March 2012 in Chicago (IL, USA).

“This could mean that consuming soy protein, for example, in combination with a DASH diet -- one that is high in fruits and vegetables, low-fat dairy and whole grains -- could lead to as much as a 10 mmHg drop in systolic blood pressure for pre-hypertensives, greatly improving their chances of not progressing to hypertension,” said lead author and study presenter graduating medical student Safiya Richardson. “Any dietary or lifestyle modification people can easily make that doesn't require a daily medication is exciting, especially considering recent figures estimating that only about one third of American hypertensives have their blood pressure under control.”

Isoflavones are produced almost exclusively by the members of the Fabaceae (bean) family. Several studies have indicated that soy isoflavones lower the incidence of breast cancer and other common cancers because of their role in influencing sex hormone metabolism and biological activity through intracellular enzymes, protein synthesis, growth factor actions, malignant cell proliferations, differentiation, and angiogenesis. Isoflavones are thought to lower SBP by increasing the production of enzymes that create nitric oxide (NO), a substance that helps to dilate or widen blood vessels, thereby reducing the pressure created by blood against the vessel walls.

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