A study published in the journal Circulation [pdf] suggests that eating tofu and other plant-based proteins rich in isoflavones may lower the risk of heart disease, particularly in younger and postmenopausal women not taking hormones.
Researchers analyzed health data of more than 74,000 women from the Nurses’ Health Study (NHS) from 1984 to 2012; approximately 94,000 women in the NHSII study between 1991 and 2013; and more than 42,000 men who participated in the Health Professionals Follow-Up Study from 1986 to 2012. All participants were free of cardiovascular disease and cancer at the beginning of each study. Researchers conducted surveys on the participants’ dietary habits every two to four years. They also collected data on heart disease from medical records and other documents, and heart disease fatalities from death certificates.
A total of 8,359 cases of heart disease were identified during 4,826,122 person-years of follow-up, which is the total number of years that study participants were free of heart disease and helps to measure how fast it occurs in a population. The researchers found that consuming tofu, which is high in isoflavones, more than once a week was associated with an 18% lower risk of heart disease, compared with those who ate tofu less than once a month. The favorable association with regularly eating tofu was found primarily in young women before menopause or postmenopausal women who were not taking hormones.
“Despite these findings, I don’t think tofu is by any means a magic bullet,” said lead author Qi Sun, a researcher at Harvard’s T.H. Chan School of Public Health, in a press release. “Overall diet quality is still critical to consider, and tofu can be a very healthy component.”
Sun noted that populations that traditionally consume isoflavone-rich diets, including tofu, such as in China and Japan, have lower heart disease risk compared with populations that follow a largely meat-rich and vegetable-poor diet. However, the potential benefits of tofu and isoflavones as they relate to heart disease need more research.
The researchers emphasized that the study should be interpreted with caution because their observations found a relationship but did not prove causality. “For example, younger women who are more physically active and get more exercise tend to follow healthier, plant-based diets that may include more isoflavone-rich foods like tofu. Although we have controlled for these factors, caution is recommended when interpreting these results,” said Sun.