Soy mixture may be alternative hormone therapy.

Dec 24, 2008

Zhao, L, Z Mao and RD Brinton. 2008. A select combination of clinical relevant phytoestrogens enhances estrogen receptor β-binding selectivity and neuroprotective activities in vitro and in vivo. Endocrinology doi:10.1210/en.2008-0715.

Synopsis by Martha Susiarjo

Eating a mix of soy compounds may be a safer way than traditional hormone therapies to protect against age-related brain disease, finds a new study that tested the mixtures in rats.

That's what scientists from the University of Southern California report from experiments in which they tested the effects of a combination of natural estrogen-like compounds. The mixture protected aging rat brains against disease without causing some of the reproductive-side effects that accompany the use of hormone replacement therapy (HRT).

The results suggest that when used together, the soy compounds may safely protect against brain decline after menopause.

Human studies are now needed to verify if the phytoestrogens would produce similar results in women.

Traditional HRT is used by older women to control symptoms of menopause. HRT has risks and benefits, including an increased risk of breast cancer but offers protection against brain diseases (for example, Alzheimer’s disease).

Scientists worked with rats and showed that a combination of the phytoestrogens genistein, daidzein and equol are as effective as the estrogen drug alone in providing brain protective effects.

Both HRT and the phytoestrogen mixture increased the amount of enzymes known to degrade proteins found in Alzheimer-diseased brains.

Additionally, they found that these combined compounds, in contrast to estrogen alone, do not increase uterine weight, an effect associated with cancer development. Like HRT, soy products may increase the risk of breast cancer because of their estrogen-like properties. The authors did not examine the effects on breast tissue in this study.