Soy provides relief from hot flashes during menopause

A recent study presented at the North American Menopause Society (NAMS) 2012 annual meeting, found eating more soy was associated with larger reductions in menopausal symptoms, such as hot flashes among women who were able to convert soy to a compound called equol.

Many women turn to natural remedies to cope with menopausal symptoms as they fear the side effects of hormone replacement therapy.  Eating tofu or drinking soya-fortified milk is often cited for its effectiveness in reducing hot flashes.

Soy contains phytoestrogens, estrogen-like plant hormones, phytoestrogens mimic the effects of estrogen in the body. Since estrogen levels drop during menopause, it is believed that a diet high in phytoestrogens can reduce menopause symptoms.

There have been mixed findings on the effectiveness of soy with some studies suggesting benefits and others showing no effect.

"Numerous studies have examined the association between soy isoflavones - from both soy foods and supplements - and menopausal Vascular Menopausal Symptoms (VMS), but with mixed results," said Belinda H. Jenks, Ph.D., Director of Scientific Affairs & Nutrition Education at Pharmavite LLC., which funded the prospective observational study. "However, they do not routinely account for whether the enrolled women can produce equol, which has documented reductions on certain VMS such as hot flashes." 

Equol is produced from the natural metabolism, or conversion, of daidzein, an isoflavone found in whole soybeans. Not everyone can produce equol after soy consumption, as the production depends on the types of bacteria present in the large intestine. About 50 percent of Asians and 20 to 30 percent of North Americans and Europeans, who in general consume less soy than Asians, have the ability to produce equol. 

The study, conducted by researchers at the Group Health Research Institute, University of Washington and the Fred Hutchinson Cancer Institute, is the first to examine equol production status and the effect of varied soy consumption on VMS in menopausal U.S. women. Evidence from prior observational studies suggests that Japanese women have milder menopausal symptoms in those who are equol producers compared to nonproducers. Additional peer-reviewed studies have documented that dietary supplements containing equol have reduced VMS symptoms in postmenopausal women who are not equol producers. 

NAMS Study Quantifies VMS Reduction in US Equol Producers 

The study found women who were equol producers and consumed higher levels of soy containing daidzein were 76 percent more likely to experience fewer hot flashes.  The positive trend in the equol producers between increased daidzein consumption and reduced VMS symptoms occurred across all four intake levels of daidzein (p=0.06). In comparison, no associations between daidzein intake and VMS were observed in the 229 equol nonproducers. 

Investigators grouped all of the women into four levels of soy consumption. The four equol producer groups averaged 28.55, 14.2, 9.01 and 4.88 milligrams of daidzein per day (mg/d) and the average daidzein intake levels in the equol nonproducers were 28.69, 13.76, 8.98 and 4.63 mg/d, which is a range comparable to general soy consumption in Asians. 

The enrolled women averaged 53 years and more than 60 percent were postmenopausal.