Written by Greg Arnold, DC, CSCS. Researchers found that soy isoflavone supplementation reduced hot flash frequency by 26.2% and severity by 26.2%.
For women between the ages of 45 and 55, menopause is a natural part of aging. It is characterized by a drop in estrogen levels which produce symptoms such as hot flashes, fatigue and weight gain (1). Significant health issues can also arise that include depression, osteoporosis and an increased risk of heart disease (2). The annual costs of treating these health issues in postmenopausal women are currently estimated at $10 billion for cardiovascular disease, $13.8 billion for osteoporosis, and $6 billion for breast cancer (3).
Of the symptoms of menopause mentioned above, hot flashes are the most common (4). Now a new review of the literature (5) suggests that soy supplementation may help with postmenopausal health, especially hot flashes.
In the review, researchers looked at data from 19 trials examining the effect of soy isoflavone supplementation on hot flash frequency and severity. They found that an average soy isoflavone supplement intake of 63 mg per day (6) for as little as 12 weeks decreased hot flash frequency by 26.2% (p = 0.001) compared with placebo. This same isoflavone intake also decreased hot flash severity by 26.2% (p = 0.001) compared with placebo.
They found that the isoflavone genestein produced beneficial effects at a specific dosage. Specifically, soy isoflavone supplementation that provided at least 18.8 mg of genistein were more than twice as effective at reducing hot flash frequency than supplementation with less than 18.8 mg of gensitein.
While the researchers admitted that “the mechanism by which soy isoflavones alleviate hot flashes has not been established…although the decline in estrogen levels as women enter menopause is almost certainly a contributing factor”, they went on to conclude that “Soy isoflavone supplements…are significantly more effective than placebo in reducing the frequency and severity of hot flashes.”
Source: Taku, Kyoko, et al. “Extracted or synthesized soybean isoflavones reduce menopausal hot flash frequency and severity: systematic review and meta-analysis of randomized controlled trials.” Menopause 19.7 (2012): 776-790.
© 2012 by The North American Menopause Society.
Posted April 9, 2012.
References:
- “Menopause” posted on the Medline Plus website.
- Cutson TM. Managing Menopause. Am Fam Physician 2000;61:1391-40,1405-6
- “Menopause” – posted on the Indiana State Department of Health website.
- Maclennan AH, Broadbent JL, Lester S, et al. Oral oestrogen and combined oestrogen/progestogen therapy versus placebo for hot flushes. Cochrane Database Syst Rev 2004;4:CD002978.
- Taku K. Extracted or synthesized soybean isoflavones reduce menopausal hot flash frequency and severity: systematic review and meta-analysis of randomized controlled trials .Menopause: The Journal of The North American Menopause Society 2012; 19 (7): DOI: 10.1097/gme.0b013e3182410159
- Khaodhiar L, Ricciotti HA, Li L, et al. Daidzein-rich isoflavone aglycones are potentially effective in reducing hot flashes in menopausal women. Menopause 2008;15:125-132.
