“Soy is an important source of protein in a plant-based diet,” says Qi Sun, MD, ScD, a researcher at Harvard’s T.H. Chan School of Public Health in Boston and the lead author of the paper. “More and more, we are realizing how important a plant-based diet is not only to human health, but also for the earth.” Dr. Sun and his team analyzed data from more than 200,000 participants involved in three different prospective studies that tracked eating habits for more than 30 years. The researchers controlled for a large swath of demographic, socioeconomic, and lifestyle information, looking at everything from exercise habits to aspirin use to smoking status to family history. They also eliminated people from the analysis once they received a cancer, diabetes, or heart disease diagnosis, since people tend to change their diet after learning of a major illness. Researchers focused on a compound in soy products called isoflavones, which have been shown to counteract inflammation, act as an antioxidant, and reduce LDL cholesterol. What’s more, isoflavones seem to stimulate the growth of beneficial anti-inflammatory bacteria in the gut microbiome. While tofu eaters had a lower risk of heart disease, the same was not true of soy milk drinkers, though soy milk is also rich in isoflavones. Researchers noted that participants consumed soy milk less often than tofu. Also, Sun notes, “Soy milk has too much sugar, emulsifiers, and additives to be considered healthy.” Isoflavones are readily available in other products, including
EdamameTempehPulses and legumes like lentils, chickpeas, and fava beansNuts including pistachios and peanuts
But isoflavones aren’t the only reason to eat soy products, notes Everyday Health’s nutritionist Kelly Kennedy, RD. “Plant-based sources of protein, like tofu, are generally significantly lower in unhealthy saturated fat and higher in healthy unsaturated fat than their meat-based counterparts. This can directly decrease the risk of heart disease and other health problems, which is why plant-based diets are so highly regarded.” RELATED: Not Eating Enough Fruits and Vegetables Contributes to Cardiovascular Death
Tofu Is No Magic Bullet to Improved Heart Health
Sun readily admits that the observational nature of the study makes it impossible to prove cause and effect, even though the researchers analyzed a robust trove of data. In all three studies, the people who frequently ate tofu also tended to have the healthiest lifestyles; they exercised more, consumed more fruits and vegetables, and ate less red meat and trans fats. Sun says, “We should step back and realize that tofu is not magic. Isoflavones are not magic. A diet is complex and has many different components, and this study adds to the evidence that soy products, particularly as a protein source, can be a part of a very healthy diet.” Kennedy agrees. “There is no one food that can be added to an unhealthy diet to ‘cure all evils,’” she says. “So while tofu can absolutely have health benefits, it’s not a free ticket to eat as much fast food as you want the rest of the time.”
