NEW YORK (Reuters Health) Jul 09 - The daily use of phytoestrogen supplements has no clinically meaningful effect on hot flashes or other menopause symptoms, according to a report published in the July 9th issue of the Journal of the American Medical Association.

Isoflavone supplements are a widely used alternative to HRT for the control of menopause symptoms. However, there are limited data supporting their efficacy and no large clinical trials have investigated their effects on such symptoms.

The current findings are in agreement with a report published last month, which showed that phytoestrogens were infective for menopausal symptoms in breast cancer patients.

In the Isoflavone Clover Extract (ICE) study, Dr. Jeffrey A. Tice, from the University of California at San Francisco, and colleagues assessed the outcomes of 252 menopausal women with frequent hot flashes who were randomized to receive one of two isoflavone supplements or placebo daily for 12 weeks.

The Promensil supplement included 82 mg of total isoflavones per day, while the Rimostil supplement included 57 mg of isoflavones. Both supplements, as well the placebo, were prepared by Novogen, Ltd. of Sydney, Australia.

The reduction in average hot flash count at 12 weeks was nearly the same in all three groups--about 5 per day, the investigators note. Promensil, but not Rimostil, did, however, appear to reduce hot flashes more rapidly than did placebo (p = 0.03).

In addition, treatment with either of the supplements was no better than placebo at improving quality of life. Both supplements appeared safe and were comparable to placebo in terms of adverse effects.

"Although the study provides some evidence for a biological effect of Promensil, neither supplement had a clinically significant effect on hot flashes or other menopausal symptoms when compared with placebo," the investigators conclude.

JAMA 2003;290:207-214.