Eating foods that contain isoflavones – a key compound in soy milk, tofu, green tea and even peanuts – every day may help young adults lower their blood pressure, say experts.
According to the researchers, the compound appears to have particular benefit in African Americans, who have hypertension prevalence rates near 42 percent.
“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,” said Safiya Richardson, a graduating medical student at Columbia University’s College of Physicians and Surgeons and the study’s lead investigator.
“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,” Richardson noted.
Compared to those consuming less than 0.33 mg of isoflavones per day, those reporting the most isoflavone intake (more than 2.5 mg per day) had a significantly lower systolic blood pressure.
To help put this into context, an 8 ounce glass of soy milk has about 22 mg of isoflavones, and 100 g of roasted soybeans have as much as 130 mg.
“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 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,” the researchers stated.
Isoflavones are thought to work 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.
Richardson said this mechanism might partially explain why the study was able to find an association with smaller amounts of isoflavone intake than examined previously.
The relatively pronounced results in the overall biracial cohort may be driven by a more intense effect of isoflavones in African Americans, Richardson said.
This is because endothelial dysfunction, a condition in which the blood vessels have a hard time either producing or using NO, plays a bigger role in hypertension in African Americans than it does in whites.
“It’s possible that these foods may help compensate for this,” Richardson said.
“Based on our results and those of previous studies, we would encourage the average adult to consider including moderate amounts of soy products in a healthy, well-balanced diet to reduce the chances of developing high blood pressure.
“For people with hypertension, it’s important that they talk with their doctor about isoflavones as a possible addition to a low sodium DASH diet that could reduce the need for medication,” she added.