Low-Fat, Vegan Diet Could Help Reduce Hot Flashes, Impact of Menopausal Symptoms in Women

Neal Barnard, MD

A study funded by the Physicians Committee for Responsible Medicine suggests implanting a plant-based diet could help lower the impact of menopausal symptoms in older women.

A 12-week, randomized, controlled trial assessing the impact of a plant-based diet rich in soy, results of the study indicate adherence to such a diet could reduce moderate-to-severe hot flashes by 84% and nearly 60% of women randomized to this approach became totally free of moderate-to-severe hot flashes.

"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 researcher Neal Barnard, MD, president of the Physicians Committee and adjunct professor at the George Washington University School of Medicine, in a statement from the Physicians Committee for Responsible Medicine.

With vasomotor menopausal symptoms a significant burden on the quality of life among many aging women, the Women's Study for the Alleviation of Vasomotor Symptoms (WAVS) trial was designed to assess compare the effects of implementing a low-fat, vegan diet or no dietary changes on the frequency and severity of hot flashes. Enrolling postmenopausal women reporting at least 2 hot flashes per day, investigators invited more than 7000 patients to take part in the trial. Of these, 155 were interviewed by telephone and a group of 38 met study criteria, underwent randomization in a 1:1 ratio, and were included in the study.

To be included in the study, patients needed to be between 40-65 years of age, without menses in the preceding 12 months, and have experienced their last period within the preceding 10 years. Exclusion criteria included use of hormonal medications, explanation for hot flashes other than natural menopause, use of weight-loss medications, history of drug use, and current consumption of a low-fat, vegan diet.

For the purpose of analysis, frequency and severity of hot flashes were recorded using a mobile phone application and vasomotor, psychosocial, physical, and sexual symptoms were assessed using the Menopause-Specific Quality of Life Questionnaire (MENQOL). Patients were given a self-calibrating scale to track body weight on a day-to-day basis. Potential associations were assessed using t-tests and chi-squared/McNemar tests.

At the end of the trial, data indicated total hot flashes decreased by 79% among those in the intervention group and by 49% among those in the control group (P=.002; between-group P=.01). Further analysis suggested the frequency of moderate-to-severe hot flashes was decreased by 84% in the intervention group compared to 42% in the control group (P=.009; between-group P=.01).

Additionally, investigators noted 59% of patients in the intervention group reported being free of moderate and severe hot flashes from 0-12 weeks (P=.002). In contrast, no change was observed for this variable among those in the control group (between-group P <.0001). Investigators also pointed out the MENQOL indicated significantly greater reductions in vasomotor (P <.0001), psychosocial (P=.04), physical (P <.002), and sexual (P=.01) domains in the intervention group compared to the control group.

"Previous studies have shown that soy could be beneficial, so we decided to put a diet change to the test," said study author Hana Kahleova, MD, PhD, director of clinical research for the Physicians Committee for Responsible Medicine, in the aforementioned statement. “We believe that the combination is what is important. 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.”

Investigators noted multiple limitations within their study for clinicians to consider when interpreting results. These limitations included the possibility of a placebo effect, a relatively small sample size, limited intervention period prohibited assessment of long-term effects, and the COVID-19 pandemic necessitating use of telemedicine mediums, among others.

This study, “The Women’s Study for the Alleviation of Vasomotor Symptoms (WAVS): a randomized, controlled trial of a plant-based diet and whole soybeans for postmenopausal women,” was published in Menopause.