The menopause typically begins to affect women around the age of 50 and may be accompanied by a range of symptoms, including hot flushes, vaginal dryness, anxiety and depression. A recent article in the Daily Express seemed to offer a simple fix by claiming a diet rich in phytoestrogens - estrogen-like compounds present in foods such as soy and lentils - can reduce the symptoms of menopause.
Chris asked the article's author, Dr Marilyn Glenville, for the evidence behind these claims and she pointed him to several published studies. These included a systematic review of 19 randomised controlled trials with a total of 1,415 participants that reported a reduction in hot flushes among women who had been randomly allocated a diet containing soy.
Was this strong enough evidence to support the claims in the Daily Express article? Sense About Science put Chris in touch with Dr Henry Boardman, a researcher at the University of Oxford, to look at the evidence provided by Glenville. He pointed out a notable omission:
"Not mentioned by Glenville was a Cochrane systematic review which included 43 randomised controlled trials and a total of 4,364 participants, larger than any of those she referenced. This review explored the impact of phytoestrogens (found in soy) for menopausal vasomotor symptoms (such as hot flushes and night sweats). The report highlighted a strong placebo effect, with hot flushes reducing by 1–59% in women who received placebo. Overall, there was no conclusive evidence that phytoestrogens reduce menopausal vasomotor symptoms.
"These mixed results do not provide strong evidence for the benefit of soy products for the treatment of hot flushes. It is likely that there is a strong placebo benefit in some women who take them. We cannot say definitively that they do not add benefit in addition to a placebo effect for the relief of hot flushes. However, the evidence does not support their recommendation for this indication."
Hormone replacement therapy is one of the recommended treatments for the symptoms of menopause. The National Institute for Health and Care Excellence (NICE) also recommends a number of alternative options, but phytoestrogens are not among them. Specifically, NICE "does not recommend the use of herbal or complementary therapies (for example soy, red clover, and black cohosh)."
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