Hot Flashes a Hot Topic

A Healthnotes Newswire Opinion

Healthnotes Newswire (June 29, 2006)—A historically controversial subject, hormone replacement therapy (HRT) has been increasingly under fire in the last two years. In 2004, the National Institutes of Health (NIH) halted two large HRT studies—one of estrogen alone and one of estrogen in combination with progestogens—because researchers found an increased risk of strokes and blood clots in the legs (estrogen alone) and of aggressive breast cancer (estrogen plus progestogens).

With the extensive media coverage of these findings, many women in their menopausal years are now uncertain about using hormones to control symptoms such as hot flashes. But experts urge women to keep the results in perspective.

“Estrogen and progestogen therapy increases the risk of breast cancer, strokes, and heart disease only slightly, after four years of use,” said Tori Hudson, ND, naturopathic physician and author of The Woman’s Encyclopedia of Natural Medicine. “Any increase in these conditions is, of course, worthy of consideration, but short term use for women with more severe symptoms may be necessary for quality of life.”

Alternatives to hormone replacement therapy

What about women whose symptoms are less severe, or who simply don’t want to take hormones? Do the alternatives to HRT work? The Journal of the American Medical Association recently published a review of the evidence on soy isoflavones, red clover isoflavones, and various nonhormonal drugs.

Out of eleven clinical trials that compared soy isoflavones with a placebo, just three showed benefit. Moreover, the quality of these three trials was rated as either fair or poor. Three other trials (rated fair in quality) found no differences in hot flash frequency compared with placebo using similar preparations. Five trials (four of which studied women with breast cancer) found no differences in severity scores with soy isoflavones compared with placebo.

“The research on soy isoflavones and hot flashes is inconsistent,” continued Dr. Hudson. “At best, it can occasionally help some women with a modest reduction in hot flashes.”

Nevertheless, some women (about 30% in Dr. Hudson’s estimation) do get relief from soy for their hot flashes. It is also worth noting that the authors of the study reviewed only trials of isoflavone extracts of soy, and did not include studies of whole soy food products. Soy contains many ingredients other than isoflavones, and researchers of previous studies have sometimes credited these other constituents for soy’s therapeutic effect.

Red clover (Trifolium pratense) isoflavones were similarly compared with placebo treatments in six trials (one trial rated “good,” three rated “fair,” and two rated “poor”). According to these researchers, only one trial reduced hot flash frequency with isoflavones from red clover. On the basis of this, the authors do not recommend red clover isoflavones as an effective means to control hot flashes.

Dr. Hudson interprets the research on red clover differently, suggesting that three of the five studies showed positive results, and that some women do benefit from the herb.

What about black cohosh?

Black cohosh (Cimicifuga racemosa), an herb that has repeatedly demonstrated efficacy for hot flashes, was not included in the new research review. However, a previous review of eight clinical trials found black cohosh extract to be both safe and effective for relief of menopausal hot flashes. Other symptoms that improved included night sweats, insomnia, nervousness, and irritability. An ongoing trial of black cohosh, sponsored by the NIH, is exploring whether black cohosh reduces the frequency and intensity of hot flashes and other menopausal symptoms.

“Black cohosh is the most studied, and has produced the best results,” says Dr. Hudson. “It should definitely be the first herb that women think of for hot flashes and night sweats.”

(JAMA 2006;295:2057–71)

Jeremy Appleton, ND, CNS, is a licensed naturopathic physician, certified nutrition specialist, and published author. Dr. Appleton was the Nutrition Department Chair at the National College of Naturopathic Medicine, has served on the faculty at Bastyr University of Natural Health Sciences, and is a former Healthnotes Senior Science Editor and a founding contributor to Healthnotes Newswire. He has worked extensively in scientific and regulatory affairs in the supplement industry and is now a consultant through his company Praxis Natural Products Consulting and Wellness Services.

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