Eating tofu and other plant-based proteins may have more health benefits than people realize, according to new research.

Foods like tofu that are rich in isoflavones – an estrogen-like substance made by soy plants – could lower risk of heart disease, particularly in younger and postmenopausal women.

"Other human trials and animal studies of isoflavones, tofu and cardiovascular risk markers also have indicated positive effects, so people with an elevated risk of developing heart disease should evaluate their diets," said lead study author Dr. Qi Sun in a news release. Sun is a researcher at Harvard's T.H. Chan School of Public Health in Boston.

"If their diet is packed with unhealthy foods, such as red meat, sugary beverages and refined carbohydrates, they should switch to healthier alternatives. Tofu and other isoflavone-rich, plant-based foods are excellent protein sources and alternatives to animal proteins."

The study, published Monday in the American Heart Association journal Circulation, examined data from 200,000 people and found eating at least one serving of tofu a week was linked to an 18% lower risk of heart disease compared to those who rarely ate tofu. Those who benefited the most were young women before menopause or postmenopausal women who were not taking hormones.

Sources of isoflavones, aside from tofu, include edamame, chickpeas, fava beans, pistachios and peanuts. Soymilk, a more processed form of soy often sweetened with sugar, was not significantly associated with lower heart disease risk in the new study.

Cultures that consume high levels of isoflavone-rich foods, such as in China and Japan, have lower heart disease risk compared to other cultures with fewer vegetables and more meat in their diets, but Sun said that association needs more research.

And research on the health benefits has been split. In 2000, the Food and Drug Administration backed claims that soy protects against heart disease, but since then studies have been inconclusive. The AHA's 2006 diet and lifestyle recommendations and a science advisory that year on soy protein, isoflavones and cardiovascular health found minimal evidence that isoflavones have any cardiovascular benefits.

Sun said eating more tofu isn't a "magic bullet" to staving off heart disease. He noted the results should be interpreted with caution because other factors – exercise, family history and lifestyle habits – can influence heart health.

"Overall diet quality is still critical to consider, and tofu can be a very healthy component."

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