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Soy or black cohosh?

26-Nov-2002

Herbal alternatives to hormone replacement therapy have mixed success, and most cannot be recommended to reduce menopausal symptoms, concludes a study published in this month's Annals of Internal Medicine.

The authors, Dr Adriane Fugh-Berman of George Washington University in Washington and Dr Fredi Kronenberg of Columbia University, New York, said that some approaches showed promise, such as the widely used herb black cohosh, but that more information was required to evaluate their safety.

The authors reviewed 29 randomised, controlled trials of CAM therapies carried out between January 1966 and March 2002, for menopausal symptoms such as hot flushes. Twelve of the studies dealt with soy or soy extracts, ten with herbs, and seven with other CAM therapies.

The authors report that soy seems to have modest benefits for hot flushes, but studies are not conclusive. Isoflavone preparations seem to be less effective than soy foods. "Soy foods have been a staple of Asian cuisine for thousands of years and are presumed safe," reported the authors.

"Supplementing the diet with beans or bean products is a benign intervention. No such presumption of safety can be made for the isolated, often high-dose isoflavones sold over the counter."

They added, however, that black cohosh may be effective for menopausal symptoms, especially hot flushes, but the lack of adequate long-term safety data (mainly on oestrogenic stimulation of the breast or endometrium) means that long-term use cannot be recommended.

Meanwhile, single clinical trials have found that dong quai, evening primrose oil, a Chinese herb mixture, vitamin E and acupuncture do not affect hot flushes, and two trials have shown that red clover has no benefit for treating the symptom.

The report concluded that black cohosh and foods that contain phytoestrogens show promise for the treatment of menopausal symptoms but that clinical trials do not support the use of other herbs or CAM therapies. It stressed, however, that there is a lack of long-term safety data on individual isoflavones or isoflavone concentrates.

Despite the warning for caution, another report on treatment for menopause symptoms, in this month's Johns Hopkins medical letter, Health After 50, finds soy to be one of the most promising remedies to overcome menopausal discomfort.

The newsletter refers to a report issued by the American College of Obstetricians and Gynecologists (ACOG) which finds that dietary soy "is a staple in Asia" and has been proposed as "one reason for the lower rate of perimenopausal symptoms reported by Asian women."

The report said that health specialists are making more recommendations for intake of soyfoods following recent findings from the Women's Health Initiative warning against hormone replacement therapy (HRT).

Other plant-based products found somewhat promising for relieving mild to moderate discomfort were black cohosh and St John's wort, a shrubby perennial with yellow flowers, according to the Johns Hopkins medical letter.

Despite the growing body of evidence on alternatives to HRT, both reports seem to confirm the lack of conclusive evidence, both on the effects and safety of all food supplements and herbal treatments for menopause symptoms.

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