Hot Flashes, Night Sweats Not Relieved by Black Cohosh

< Dec. 20, 2007 > -- The popular herbal supplement black cohosh is no better than a placebo at relieving hot flashes and night sweats in perimenopausal and postmenopausal women, according to a new study published in the Annals of Internal Medicine.

That finding may come as bad news to American women who have been looking for ways to ease menopausal symptoms ever since 2002 research linked hormone replacement therapy (HRT) to a higher risk for breast cancer.

The study was funded by the US National Institute on Aging and the National Center for Complementary and Alternative Medicine (NCCAM).

According to NCCAM, black cohosh is made from the roots and stems of a flowering plant also known as black snakeroot or bugbane.

"We were hopeful that black cohosh would prove to be effective for menopause symptoms because options are fairly limited," says the study's lead author, Katherine M. Newton, Ph.D., of the Group Health Center for Health Studies in Seattle, Wash. "Finding a safe and effective alternative to hormone therapy would have been a tremendous benefit to women," she adds.

Randomized Trial Shows Little Effect

The study results came from the Herbal Alternatives (HALT) for Menopause Study, a 12-month randomized, double-blind, placebo-controlled trial in which 351 women ages 45-55 were randomly assigned to one of five interventions: black cohosh; a multi-botanical supplement containing black cohosh and several other herbs; a multi-botanical supplement plus dietary counseling to increase soy consumption; HRT consisting of estrogen with or without progesterone; or a placebo.

Of the five interventions, only hormone replacement therapy effectively reduced menopausal symptoms - by an average of four symptoms per day - compared to a placebo, the team reports. The other interventions only reduced symptoms by an average of about half a symptom per day.

Dr. Newton and her team were midway through the study when the Women's Health Initiative first reported in 2002 that HRT was associated with an increased risk of breast cancer.

To protect participants, "when these findings were released, all women currently in the study were re-consented with this new information and given the option of knowing if they were on hormone therapy," Dr. Newton says.

"All new participants were given the option of participating without being assigned to hormone therapy. As further information from the Women's Health Initiative was published, we stopped randomization to hormone therapy completely," adds Dr. Newton.

Unlike many drug trials that limit participation to women who have at least seven hot flashes per day, Dr. Newton's study lowered this threshold to two hot flashes per day.

 "We wanted to test black cohosh in women with a range of symptoms," she says. "When we looked to see if our findings differed among women with six or less vs. seven or more hot flashes a day, the results were the same."

The results were less conclusive in the soy-intervention group because most participants ended up consuming only one serving of soy per day instead of the recommended two servings per day. "So, it remains possible that a larger increase in soy intake might be of benefit," Dr. Newton says.

One Expert Says Study Inconclusive

Dr. Mary Hardy, medical director of integrative medicine at the Ted Mann Family Resource Center at the University of California, Los Angeles, who was not part of the study, says the research was well-designed but had weaknesses.

"The most you can say about this study is that one particular extract of black cohosh doesn't work," she says. "It's very difficult to damn a whole category of herbal products based on one study, because there's so much individual variation in extraction."

And, she adds, because the study only used one black cohosh extract - supplied by New Jersey-based Pure World Inc. - its results may not be generally applicable.

The two best-studied extracts - RemiFemin® and Klimadynon - have shown mostly positive results in the treatment of menopausal symptoms, Dr. Hardy says. "I have used both of these preparations in my clinical practice and have seen good results. This study has not convinced me to stop prescribing black cohosh for my patients," she adds.

In Dr. Hardy's experience, black cohosh is not often as quickly effective as hormone replacement therapy in relieving menopausal symptoms. "But there is a significant clinical response, which is amplified by lifestyle adjustments, such as stress-reduction techniques and avoiding triggers - such as alcohol and caffeine - which can make hot flashes worse," she says. "I think herbal interventions are a reasonable choice for women at or around perimenopause because they're generally quite safe."

Because black cohosh does not have the estrogenic effects of HRT or the estrogen-like effects of soy, it is unlikely to increase the risk of breast cancer, Dr. Hardy says.

"To me, soy is not so useful as an adjunct to control hot flashes, although people respond very nicely to it," she says "It's useful because it's heart-healthy, since cardiovascular risk is something women going through menopause need to worry about."

More Study Needed

Dr. Newton says that her study does not definitively prove that black cohosh is useless in treating menopausal symptoms.

"It would be unusual, and perhaps inappropriate, for a single study to completely put the question to rest," she says. "There are currently other well-designed trials being conducted that will add further to the information about black cohosh."

But the study does give women cause for optimism, she adds, because it showed that hot flashes usually disappear within four years regardless of treatment.

"Patience and the use of behavioral interventions such as avoiding triggers - very hot or spicy foods, or alcohol for some women - keeping a fan or ice water at hand, dressing in layers and sleeping in a cooler room are good options for many women," Dr. Newton says.

"For those with intolerable symptoms, we still recommend a discussion with their health care provider about other options," she adds.

Always consult your physician for more information.

More About Menopause

When a woman permanently stops having menstrual periods, she has reached the stage of life called menopause.

Often called the "change of life," this stage signals the end of a woman's ability to have children. Many physicians actually use the term menopause to refer to the period of time when a woman's hormone levels begin to change. Menopause is said to be complete when menstrual periods have ceased for one continuous year.

The transition phase before menopause is medically referred to as climacteric, but more recently perimenopause. During this transition time before menopause, the supply of mature eggs in a woman's ovaries diminishes and ovulation becomes irregular. At the same time, the production of estrogen and progesterone decreases.

It is the enormous drop in estrogen levels that causes most of the symptoms commonly associated with menopause.

While the average age of menopause is 51, menopause can actually occur any time between the ages of 40 and 55. Women who smoke and are underweight tend to experience an earlier menopause, while women who are overweight often experience a later menopause.

Generally, a woman tends to experience menopause at about the same age as her mother did.

Hot flashes appear as a result of decreasing estrogen levels. In response to this, a woman's glands release higher amounts of other hormones that affect the brain's thermostat, causing the body temperature to fluctuate.

Hormone replacement therapy (HRT) has been shown to relieve some of the discomfort of hot flashes for many women. However, the decision to start the supplementation or replacement of these hormones should be made only after you and your physician have evaluated the risks and benefits  based on your individual medical history.

Practical non-medication-related suggestions for coping with hot flashes include:

• Dress in layers, so that you can remove clothing when a hot flash begins.

• Avoid foods and beverages that may cause hot flashes, such as spicy foods, alcohol, coffee, tea, and other hot beverages.

• Drink a glass of cold water or fruit juice when a hot flash begins.

• Reduce your stress level, which may aggravate hot flashes.

• Keep a thermos of ice water or an ice pack next to your bed during the night.

• Use cotton sheets, lingerie, and clothing that allow your skin to breathe.

• Keep a diary or record of your symptoms to determine what might trigger your hot flashes.

Always consult your physician for more information.