The researchers also found that isoflavones may be of particular benefit for black American adults, nearly 42 percent of whom are estimated to have high blood pressure, also known as hypertension.
One expert not connected to the study said there is reason to believe that isoflavones could help the heart.
Isoflavones “dilate the vessels by increasing the release of nitric oxide,” explained Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City. She said the new study, “brings to light a compelling dietary recommendation that can help control hypertension in younger patients.”
In the new study, investigators examined data from more than 5,000 participants in a major study funded by the U.S. National Institutes of Health.
The analysis revealed that those who consumed the highest amounts of isoflavones per day (more than 2.5 milligrams [mg]) had an average 5.5 mmHg lower systolic pressure (the top number in a blood pressure reading) than those who consumed less than 0.33 mg of isoflavones per day.
To understand what that means to the everyday diet, an 8-ounce glass of soy milk has about 22 mg of isoflavones and 100 grams of roasted soybeans have as much as 130 mg of isoflavones, the researchers explained.
The study was to be presented Sunday at the annual meeting of the American College of Cardiology (ACC) in Chicago.
“What’s unique about this study is that the results are very applicable to the general population. Our results strongly suggest a blood pressure benefit for moderate amounts of dietary isoflavone intake in young black and white adults,” lead investigator Safiya Richardson, a graduating medical student at Columbia University’s College of Physicians and Surgeons in New York City, said in an ACC news release.
“Our study is the first to show a benefit in African-Americans, who have a higher incidence of high blood pressure, with an earlier onset and more severe end-organ damage,” she added.
The findings “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 [people on the threshold of high blood pressure], greatly improving their chances of not progressing to hypertension,” Richardson said.
“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,” she added.
It’s believed that isoflavones boost the body’s production of enzymes that create nitric oxide, which helps to widen blood vessels and thereby reduce blood pressure.
Findings presented at medical meetings are typically considered preliminary until published in a peer-reviewed journal.
— Robert Preidt
source: HealthDay Suzanne Steinbaum, MS, director of Women and heart disease, Lenox Hill Hospital, New York City; American College of Cardiology, news release, March 25, 2012