Summary: Switching to a diet low in animal products and fats, high in vegetables, and adding a serving of soybeans reduced hot flashes and increased weight loss in menopausal women by up to 88%.
Source: Physicians Committee for Responsible Medicine
A new study, published by the North American Menopause Society in the journal Menopause, found that a diet intervention is about as effective (88%) as hormone replacement therapy (70%-90%) for reducing menopausal hot flashes, without the associated health risks.
The WAVS trial—the Women’s Study for the Alleviation of Vasomotor Symptoms—found that a plant-based diet rich in soy reduced moderate to severe hot flashes by 88% and helped women lose, on average, eight pounds in 12 weeks.
“We do not fully understand yet why this combination works but it seems that these three elements are key—avoiding animal products, reducing fat, and adding a serving of soybeans,” explains lead researcher Neal Barnard, MD, president of the Physicians Committee and adjunct professor at the George Washington University School of Medicine.
“Our results mirror the diets of places in the world, like pre-Westernized Japan and modern-day Yucatán Peninsula, where a low-fat, plant-based diet including soybeans is more prevalent and where postmenopausal women experience fewer symptoms.”
The study published today is the second phase of a two-part trial, the first of which was also published in Menopause in 2021. The fall timing of the first trial raised the question of whether this symptomatic improvement might have been attributed to cooler temperatures. But women who began the study as weather warmed up in the spring had the same benefit, ruling out the effect of outside temperature.
“These new results suggest that a diet change should be considered as a first-line treatment for troublesome vasomotor symptoms, including night sweats and hot flashes,” explains Dr. Barnard.
Included in the study were 84 postmenopausal women reporting two or more hot flashes per day. They were randomly assigned either to an intervention group—consisting of a low-fat, vegan diet, including half a cup of cooked soybeans daily—or to a control group that made no diet changes for 12 weeks.
“This study demonstrates the effectiveness of a dietary intervention for menopausal symptoms,” Dr. Barnard explains. “As well, it is precisely the diet that would be expected to reduce the health concerns of many women reaching menopause: an increasing risk of heart disease, breast cancer, and memory problems.”
A dietary intervention for vasomotor symptoms of menopause: a randomized, controlled trial
Postmenopausal vasomotor symptoms disrupt quality of life. This study tested the effects of a dietary intervention on vasomotor symptoms and menopause-related quality of life.
Postmenopausal women (n = 84) reporting at least two moderate-to-severe hot flashes daily were randomly assigned, in two successive cohorts, to an intervention including a low-fat, vegan diet and cooked soybeans (½ cup [86 g] daily) or to a control group making no dietary changes. During a 12-week period, a mobile application was used to record hot flashes (frequency and severity), and vasomotor, psychosocial, physical, and sexual symptoms were assessed with the Menopause-Specific Quality of Life questionnaire. Between-group differences were assessed for continuous (t tests) and binary (χ2/McNemar tests) outcomes. In a study subsample, urinary equol was measured after the consumption of ½ cup (86 g) of cooked whole soybeans twice daily for 3 days.
In the intervention group, moderate-to-severe hot flashes decreased by 88% (P < 0.001) compared with 34% for the control group (P < 0.001; between-group P < 0.001). At 12 weeks, 50% of completers in the intervention group reported no moderate-to-severe hot flashes at all. Among controls, there was no change in this variable from baseline (χ2 test, P < 0.001). Neither seasonality nor equol production status was associated with the degree of improvement. The intervention group reported greater reductions in the Menopause-Specific Quality of Life questionnaire vasomotor (P = 0.004), physical (P = 0.01), and sexual (P = 0.03) domains.
A dietary intervention consisting of a plant-based diet, minimizing oils, and daily soybeans significantly reduced the frequency and severity of postmenopausal hot flashes and associated symptoms.