UD's Melissa Melby is co-author of a study that finds soy may offer an alternative to hormone therapy for hot flashes in menopause.

Soy and menopause

Large-scale study finds soy may alleviate hot flashes in menopause

TEXT SIZE

1:42 p.m., April 4, 2012--In the most comprehensive study to date to examine the effects of soy on menopause, researchers have found that two daily servings of soy can reduce the frequency and severity of hot flashes by up to 26 percent, compared to a placebo. 

The findings, published in Menopause: The Journal of the North American Menopause Association, reviewed 19 previous studies that examined more than 1,200 women. 

Research Stories

Battling RRD

UD's Tom Evans is part of a research group that has been awarded $4.6 million by the U.S. Department of Agriculture to study methods to combat rose rosette disease.

Penguin chicks

UD oceanographers recently reported a connection between local weather conditions and the weight of Adélie penguin chicks in Marine Ecology Progress Series, a top marine ecology journal.

Although the effectiveness of soy in alleviating hot flashes has been inconclusive, with some studies suggesting soy to be beneficial and others suggesting otherwise, much of the discrepancy is due to small sample sizes and inconsistent methodology, according to the authors. 

“When you combine them all, we’ve found the overall effect is still positive,” said Melissa Melby, an assistant professor of medical anthropology at the University of Delaware and co-author of the study. 

Examining the impact of soy isoflavones, chemicals found in soy that exert a mild estrogen-like effect, Melby and her colleagues found:

  • Ingesting at least 54 milligrams of soy isoflavones daily for six weeks to a year reduces menopause hot flash frequency by 20.6 percent and severity by 26 percent, compared to a placebo. 
  • The total reduction in frequency and severity might be even greater due to the placebo effect. 
  • In longer duration studies (where women consumed soy isoflavones for 12 weeks or more), the decrease in hot flash frequency was approximately threefold greater than in shorter-duration trials. 
  • Isoflavone supplements with higher levels (at least 19 milligrams) of genistein, one of the two main types of isoflavones, were more than twice as effective at reducing hot flash frequency than lower amounts. 

Melby called the genistein result particularly notable because the compound is the primary isoflavone in soybeans and soy foods, suggesting that, “Eating soy foods, or using supplements derived from whole soybeans, may work better for women.”

Each gram of soy protein in soybeans and traditional soyfoods provides approximately 3.5 mg of isoflavones. Two glasses (16 oz) of soymilk or seven ounces of tofu provide approximately 50 mg of isoflavones.

The interest in soy and menopause stems from observational evidence in Japan, where researchers have found the low frequency of hot flashes in Japanese women might be attributed to the high soy consumption that often begins in utero and continues throughout their lifespan. 

“Soy is probably more effective in these women,” Melby said. “But if you’re 50 and you’ve never touched soy, it’s not too late. We’ve found that it still helps.” 

Article by Artika Rangan Casini

Photo by Kathy F. Atkinson

icon-fb icon-tw icon-yt icon-fs
ADVERTISEMENT

News Media Contact

University of Delaware
Office of Communications & Marketing
302-831-NEWS
ud-ocm@udel.edu

UDaily is produced by the
Office of Communications & Marketing

The Academy Building
105 East Main Street
University of Delaware
Newark, DE 19716 | USA
Phone: (302) 831-2792
email: ud-ocm@udel.edu
www.udel.edu/ocm
University of Delaware • Newark, DE 19716
ud-ocm@udel.edu • (302) 831-2792 • ©2012
University of Delaware • Newark, DE 19716 • USA • Phone: (302) 831-2792 • © 2013
Comments|Contact Us|Legal Notices