Some People Benefit from Soy More Than Others

March 29th, 2017

We’ve probably all heard about the health benefits of soy. But, new research shows that those health benefits don’t appear to be the same for everyone.

“Scientists have known for some time that isoflavones [small nutrients found in dietary soy] protect against the buildup of arterial plaque  in monkeys and are associated with lower rates of heart disease in people in Asian countries,” according to Akira Sekikawa, MD, PhD, MPH (Epidemiology, Pitt Public Health). Soy’s benefits, however, do not extend to all populations. “We were surprised when a large trial of isoflavones in the United States didn’t show the beneficial effects among people with atherosclerosis in Western countries. Now, we think we know why.”

The “why” has to do with something called “equol”—a substance made by some types of gut bacteria when they metabolize isoflavones. Research has found that Japanese men who are able to produce equol have lower levels of a risk factor for heart disease than those people who cannot produce it. In Asian countries, 50 to 60 percent of people produce equol, compared to only 20 to 30 percent of people in Western countries. Dr. Sekikawa and his team found that the people who can produce equol had 90 percent lower odds of coronary artery calcification, a predictor of heart disease.