New Research Shows That Soy Doesn't Prevent Bone Loss Or Help With Menopause Symptoms

Women who consume soy supplements thinking…hoping… that they will help reduce or eliminate menopausal symptoms such as bone loss, insomnia or hot flashes will be very disappointed at the findings of a clinical trial published in the Archives of Internal Medicine.

I know this study well as I worked on it for 3 years at the University of Miami—managing and analyzing the data—and co-authored the paper with Dr. Silvina Levis (see our previous Q & A on Vitamin D with Dr. Levis) and colleagues.

The study targeted women ages 45-60 years who had been menopausal for one to five years. We wanted to determine whether daily intake of soy isoflavones (plant compounds that mimic estrogen in the body) in tablet form prevents the rapid bone loss associated with the initial menopausal years.

In this study of 248 women ages 45 to 60, half were were given 200 milligrams of soy isoflavones daily (a much bigger dose than you or I would ever consume) and the other half were given a placebo. At the outset, nearly all complained of the most common menopausal symptoms, including hot flashes, night sweats and insomnia. loss.

After two years, the study participants were tested for changes in bone mineral density and in menopausal symptoms. Despite the large dose of soy isoflavones, researchers found no difference in the rates of bone loss between the two groups. There also was no significant change in other symptoms such as hot flashes. In fact, by the end of the study, more women in the soy group reported hot flashes compared to the placebo group, 48 percent to 32 percent. Moreover, almost all of the participants (those taking the soy tablets as well as the placebo) reported adverse effects such as constipation and bloating.

In the end, the study showed that soy isoflavones are too weak an estrogen to make a difference and can’t be considered a remedy for menopausal symptoms or prevention of bone loss. Women will need to reach out to more traditional modalities to prevent bone loss and hot flashes, including the use of FDA approved drugs and exercise.