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Study casts doubts on cohosh's effect


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Dietary supplements containing black cohosh, an herb widely used by women seeking relief from menopause symptoms, were no more effective in reducing hot flashes than a sugar pill, says a National Institutes of Health-funded study out today.

Sales of black cohosh supplements soared after an NIH-sponsored study in 2002 reported that hormone therapy -- the most effective treatment for menopause symptoms -- raised users' risk of heart attacks, breast cancer, blood clots and stroke. U.S. black cohosh sales rose 26% from 2002 to 2003 to $15.7 million, according to the Natural Foods Merchandiser, a trade magazine.

Mark Blumenthal, head of the American Botanical Council, a research and education group in Austin says black cohosh sales are probably actually several times higher because sales data generally exclude supplements purchased at Wal-Mart, Costco or Sam's Club, from doctors, through the mail or online.

Remifemin is the top single-ingredient black cohosh product, representing 40% of sales in drugstores, supermarkets and mass- marketers such as Target, says Terri Slater, spokeswoman for Enzymatic Therapy, which sells it in the USA.

Authors of the new report in the Annals of Internal Medicine say theirs is the largest and longest study to compare black cohosh to a placebo. They randomly divided 351 women, ages 45 to 55, into five year-long treatment groups:

*Hormone therapy.

*160 milligrams a day of black cohosh (not Remifemin).

*A supplement containing 200 milligrams of black cohosh as well as other botanicals.

*The multibotanical supplement along with counseling to increase consumption of soy foods.

*A placebo.

Neither the women nor the researchers knew who was getting which treatment.

The researchers stopped enrolling women into the hormone group after the NIH-sponsored study came out in 2002.

The women, all of whom were members of the Group Health Cooperative, a health maintenance organization based in Seattle, had to have at least two hot flashes a day to enroll. On average, they had six.

After three, six and 12 months of treatment, researchers found no significant difference in hot flashes between the black cohosh groups and the placebo group, in which women saw a 30% reduction in severity and frequency of hot flashes by the study's end. Only hormone therapy was more effective.

Lead author Katherine Newton, a Group Health Cooperative epidemiologist, notes that most studies of hot-flash remedies show a similar benefit in the placebo group. Possible explanations: the placebo effect or the fact that symptoms subside over time, with or without treatment, she says.

Blumenthal says Newton's trial is not definitive. Among alternative medicines, he says, "black cohosh seems to be the leading product'' for menopause symptoms.

In an accompanying editorial, UCLA internist Carol Mangione says the well-designed study "makes an important contribution, albeit one that will disappoint women who have been hoping for an effective, safe alternative to estrogen."

To see more of USAToday.com, or to subscribe, go to http://www.usatoday.com

© Copyright 2006 USA TODAY, a division of Gannett Co. Inc.

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