Can a Daily Serving of Soybeans Dramatically Reduce Hot Flashes? Science Says Yes

Great news for the more than 80 percent of women who experience hot flashes in their menopausal years: A groundbreaking study recently published in the journal Menopause found that a plant-based diet including a daily dose of soybeans dramatically curtails these sweaty episodes. We talked to study author Neal Barnard, MD, FACC, president of the Physicians Committee for Responsible Medicine and author of Your Body in Balance: The New Science of Food, Hormones, and Health, about his findings.

Can you describe your study?

Dr. Neal Barnard: We asked women ages 45 to 60 to eat a low-fat plant-based diet with a daily half-cup serving of whole soybeans for 12 weeks. The outcomes were striking. Overall, hot flashes dropped nearly 80 percent. But what was most important was moderate to severe hot flashes dropped by 84 percent—so on average from five or six a day to one. Sixty percent of the women stopped having moderate or severe hot flashes whatsoever. When you see studies of someone who takes an extract of soy isoflavones from the health food store, you only get about a 40 percent improvement. So this is a really big finding.

Why whole soybeans and not edamame?

NB: Soybeans contain isoflavones, which have a natural ability to knock out hot flashes. So you could use edamame, tofu, soy milk, or soy yogurt, but ... edamame is a juvenile soybean. Mature whole soybeans have a substantially higher isoflavone content.

Would eating soybeans without a low-fat plant-based diet work?

NB: A plant-based diet supports healthy gut bacteria that convert isoflavones into their most powerful form, called equol, to really cool down hot flashes. Your average meat-eating American can eat soybeans all day long and get some benefit, but it won’t be the same.

Hot flashes usually taper off at some point. Do you recommend still eating soybeans?

NB: Menopause is a time when many women are also concerned about weight gain, heart problems, breast cancer risk, thyroid issues, and diabetes. A plant-based diet is powerful for all these things, and soybeans reduce cancer risk and cut down cholesterol. Your hormones control every aspect of your biology, and foods affect hormonal action. Our research participants felt their lives were transformed.

Try It at Home

Study participants were sent Laura Soybeans purchased from Amazon (you can also find soybeans at health food stores) and an Instant Pot. They were encouraged to batch-cook on Sundays and portion the soybeans into half-cup servings. “They would use them like pine nuts on a salad or add them to a soup,” Barnard says. “We also discovered if you bake [soaked soybeans] for 45 minutes, they roast up really nicely with a little spice ... like dry-roasted peanuts.”

Ready to get started? Check out Forks Meal Planner, FOK’s easy weekly meal-planning tool to keep you on a healthy plant-based path. To learn more about a whole-food, plant-based diet, visit our Plant-Based Primer.