Study Confirms Soy Isoflavones Reduce Menopausal Hot Flashes
Archer Daniels Midland Company is pleased to share the results of a new meta-analysis on the effects of soy isoflavones in the alleviation of menopausal hot flashes. The analysis, which was published March 19 by Menopause: The Journal of The North American Menopause Society, found clear and consistent evidence that soy isoflavone supplements, like NovaSoy brand soy isoflavones, are significantly more effective than placebo in reducing the frequency and severity of hot flashes.
"The key finding in this study is that when you limit the analysis to isoflavone supplements derived from soy or those with profiles identical to soy, there is a very consistent effect on hot flash relief," said Mindy S. Kurzer, PhD, professor of nutrition at the University of Minnesota, hormone expert and contributing author to the study. "Almost all studies in the meta-analysis show a consistent reduction in hot flash frequency and severity."
The meta-analysis—which is the largest and most comprehensive conducted to date – revealed that ingestion of soy isoflavones for six weeks to 12 months significantly reduced the frequency of hot flashes by more than 20 percent compared with placebo. Soy isoflavones also significantly reduced hot flash severity by more than 26 percent compared with placebo. The analysis found that the decrease in hot flash frequency in longer duration trials (more than 12 weeks) was approximately threefold greater than the decrease in shorter-duration trials.
"For women who are bothered by hot flashes, any reduction in frequency or severity may be welcome – especially if it can be achieved without side effects," said Melissa K. Melby, PhD (University of Delaware), hot flash expert and contributing author to the study. "Soy isoflavones appear to be a good first approach to alleviating hot flashes. Since there is often a large placebo effect, women taking supplements with the right soy isoflavone profile will likely see at least a 50 percent reduction compared to doing nothing."
Though many different isoflavones exist in nature, the three found in soy are genistein, daidzein and glycitein. According to the authors of the study, isoflavone supplements providing higher amounts of genistein were approximately 50 to 200 percent more potent at reducing hot flash frequency than isoflavone supplements containing lower amounts of genistein.
"Supplements providing a total of 50 mg of total isoflavones will be effective as long as they also provide at least 19 milligrams of genistein," said Mark Messina, PhD, soy expert, industry consultant and contributing author to the study.
"We are pleased that such a thorough evaluation of the most well-conducted studies showed that soy isoflavones are highly effective for the alleviation of hot flashes," said Steve O'Brien, product manager of Natural Health and Nutrition at ADM. "To maximize relief, ADM's NovaSoy brand soy isoflavones reflect the same profile of isoflavones naturally present in soy, including higher amounts of genistein."
"Hot flashes are one of the most common symptoms of menopause," added Messina. "For women with moderate-to-severe hot flashes who are seeking relief from symptoms, the reduction in the number and severity of hot flashes observed in our analysis in response to soy isoflavones will likely result in a significant improvement in quality of life."
A meta-analysis is a statistical analysis of a large number of studies for the purpose of integrating the findings. Of the 17 studies included in the meta-analyses, 13 trials (including 1,196 women) evaluated hot flash frequency, and nine trials (including 988 women) evaluated hot flash severity.
The analysis was conducted by Kyoko Taku, PhD, MD (National Institutes of Health, Japan); Melby; Fredi Kronenberg, PhD (Stanford University); Kurzer; and Messina. The complete article will be published in the July issue of Menopause.
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