Soybeans help reduce 'hot flashes' during menopause

The study was conducted by scientists at George Washington University School of Medicine and published in the medical journalMenopause. Results showed that postmenopausal women on a plant-based diet who consumed 86 grams of cooked soybeans per day had an 88% reduction in moderate to severe hot flashes. After 12 weeks, half of the women in the study no longer had severe hot flashes.

Professor Neal Barnard, the lead researcher, said the diet was more effective than expected, comparable to the effects of hormone therapy. It also produced healthy, easy-to-follow weight loss. People on the diet lost an average of 3.6kg over 12 weeks, while the control group lost an average of 0.2kg.

Previous studies have shown that women in Japan and other countries with traditional diets rich in plant foods such as rice, soybeans and vegetables rarely experience hot flashes. However, as diets have become Westernized, with increased consumption of dairy products and meat, hot flashes have become more common.

Barnard began researching the effects of a vegan diet on hot flashes after receiving a tip from a woman who had read the bookYour Body in BalanceHis book explores the impact of diet on hormones and health.

“She said the method in the book cured her hot flashes in just a few days. It was even more effective than what I promised in the book,” Barnard said. The woman said she adopted a vegan diet, cut down on fat, and added half a cup of cooked soybeans a day.

Barnard and his team tested this very approach in a randomized study of 84 women, each of whom reported at least two moderate to severe hot flashes per day. Half of the women were placed on a low-fat vegan diet and ate a half-cup of soy each day, while the other group continued to eat as usual. They then recorded the frequency and severity of their hot flashes.

Study participant Sherri reported a significant improvement in her quality of life, no longer experiencing uncomfortable hot flashes. She was able to spend more time with her four children and felt better overall.

“I was nervous about going on hormone therapy, so I welcomed the dietary changes,” Sherri says. Before considering medication, she tried the method because it was simple, easy to do, and had immediate results.

Barnard said a vegan diet alone had little effect on hot flashes. Soy and soy extracts also had little effect. However, combining the two, along with avoiding foods high in oils like nuts, butter, and vegetable oils, significantly reduced hot flashes.

“We don’t know exactly why, but avoiding fatty foods seems to be helpful. All three factors seem to play a role,” says Barnard.

Soybeans may help reduce the risk of breast cancer due to the presence of natural isoflavones such as genistein, daidzein, and glycitein, which are phytoestrogens that mimic plant estrogen. In this study, the diet used cooked soybeans, which contain higher levels of isoflavones than edamame (young soybeans in the shell), soy milk, or tofu.

Barnard explains that the isoflavones in soy act as natural remedies to reduce hot flashes. He notes that while soy milk or tofu are healthy foods, they don't have the same powerful effects as cooked soybeans.

He said that while the full benefits of a plant-based diet are not yet clear, the high fiber and low fat content play an important role. They often modulate the effects of estrogen and have been found to be effective for menstrual cramps. It is likely that women who prefer a plant-based diet have lower estrogen levels and less fluctuations when they enter menopause. Furthermore, plant-based diets also promote weight loss, which can reduce hot flashes.

Marta, who took part in the study, had been unable to find any other solution. She said her hot flashes were very severe before joining the study. She suffered from them almost every hour, along with night sweats. After adopting the diet, she felt better, had more energy, and slept better at night. Her hot flashes were significantly reduced.

"I wouldn't go back to the American diet because I feel like my health is under control," Marta said.