Soy-rich diet helps relieve hot flashes in postmenopausal women

Following a plant-based diet rich in soy leads to significant reductions in frequency and severity of hot flashes in postmenopausal women without the need to use drugs, according to the WAVS* study.

“This is a game changer for women aged 45 and over, most of whom we now know can get prompt relief from the most severe and troubling menopause symptoms without drugs,” said lead author Dr Neal Barnard from George Washington University School of Medicine, Washington, DC, US.

In the study, 38 postmenopausal women who reported ≥2 episodes of hot flashes per day were randomized to follow a low-fat, vegan diet or no changes to existing diet for 12 weeks. The vegan diet was based on vegetables, fruits, whole grains, and included half cup of cooked whole soybeans daily. [Menopause 2021;doi:10.1097/GME.0000000000001812]

After 12 weeks, the number of total hot flashes declined by 79 percent in the vegan diet group compared with a drop of 49 percent in the control group (p=0.01).

Specifically, the frequency of moderate-to-severe hot flashes decreased by 84 percent in the vegan group, from almost five episodes per day to fewer than one episode per day while the control group only saw a reduction by <2 episodes per day (p=0.01).

More than half of the women on vegan diet were free of moderate and severe hot flashes at the end of week 12 whereas no significant changes were seen in the control group (p<0.001).

In addition, women following the vegan diet also experienced significant improvements in quality of life, as assessed on the The Menopause-Specific Quality of Life Questionnaire (MENQOL). Vegan diet led to significantly greater reductions across various domains measured including vasomotor (p<0.0001), physical (p<0.002), psychosocial (p<0.04), and sexual (p<0.01) domains.

“Body weight also decreased significantly in the intervention group,” reported the researchers, who noted that vasomotor symptoms affect up to 80 percent of menopausal women in the Western countries.

Soy products have been shown to reduce hot flashes by a modest amount in previous randomized trials. Researchers believed that isoflavones contained in soy products may be the underlying compound mediating their beneficial effects of alleviating postmenopausal symptoms.

Isoflavones are metabolized in the gut to produce equol, which is a nonsteroidal compound associated with reduced hot flashes. In addition, vegetarians have also been shown to have higher levels of equol than those on non-vegetarian diet.

“We believe that the combination [of soy and vegan diet] is what is important,” said study co-author Dr Hana Kahleova, who was a member of the Physicians Committee for Responsible Medicine, Washington, DC, US.

“By the end of the study, the majority of women on a plant-based diet rich in soy reported that they no longer experienced moderate-to-extreme hot flashes at all and that they experienced significant improvements in their quality of life,” she pointed out.

Importantly, relief of these troublesome menopausal symptoms was achieved without the used of hormone medications or extracts, the researchers highlighted.

*WAVS: Women’s Study for the Alleviation of Vasomotor Symptoms