Isoflavones and Menopausal Symptoms
Isoflavones and Menopausal Symptoms
Hot flashes commonly occur in women during the pre-menopausal and menopausal periods of life. Often uncomfortable, these sudden flashes of warmth are caused by fluctuation and/or rapid changes in estrogen hormonal levels. Fortunately, not all women are affected. Those who are may experience symptoms that last only a few years, while other women may have symptoms that linger for more than a decade.
Concerns for side effects from hormone replacement medications have led many women to consider more natural alternatives to improve menopausal symptoms. Soy isoflavones are one such alternative.
A 2013 study on isoflavones, by Cochrane Review, looked at 43 randomized controlled trials, which included a total of 4,364 participants. Researchers felt a strong placebo effect was present. Overall, they concluded there was no conclusive evidence of the benefit of isoflavones. However, the researchers did comment that four trials that were not included — which included patient intake of 30 grams or more of genistein — did show isoflavone benefit in preventing hot flashes. Therefore, if you are consuming a soy isoflavone supplement for hot flashes and night sweat symptoms, ensuring the presence of genistein should be considered. This ingredient should be listed on the label.
A 2015 isoflavone meta-analysis and systematic review study analyzed 15 randomized controlled trials that included women ranging in age from 49 to 58 years. Based on the findings, the researchers concluded: “Phytoestrogens appear to reduce the frequency of hot flashes in menopausal women, without serious side-effects.”
A 2015 study compared soy isoflavones to estradiol, a prescription medication frequently prescribed by doctors. The results showed that more time was needed for the soy isoflavones to be effective in controlling menopausal symptoms. Specifically, at 13 weeks, isoflavones achieved half of their total effectiveness and required 48 weeks to reach 80 percent of their effectiveness. Alternatively, prescription estrogen required three weeks to become effective. Consult with a physician for the best option for individual needs.
A 2016 review published in the Journal of the American Medical Association (JAMA) reviewed 62 studies that included 6,653 women. They found that the use of phytoestrogens that included isoflavones was associated with a decrease in the number of hot flashes and reduced vaginal dryness, both common menopausal symptoms. However, there was no difference in night sweats. Additional studies were recommended.
Lastly, a 2017 double-blind, randomized controlled trial found that the combination of red clover isoflavones (>34 grams/day) and probiotics was more effective than a placebo alone in reducing hot flash symptoms in this 12-week study.
References:
Chen MN, Lin CC, Liu CF. Efficacy of phytoestrogens for menopausal symptoms: a meta-analysis and systematic review. Climacteric. 2015;18(2):260–269. doi:10.3109/13697137.2014.966241
