New studies have found that commonly used natural plant-based drugs do not have an effect on hot flashes or on cognitive function in menopausal women.
In one study, the botanicals black cohosh and red clover were compared to the standard of care — hormone therapy — and to placebo for the treatment of hot flashes.
The research will be published in an upcoming issue of Menopause, the journal of The North American Menopause Society.
Researchers at the University of Illinois at Chicago and Northwestern University enrolled 89 women with moderate to severe hot flashes in a four-arm, randomized, double-blind clinical trial.
The women, who experienced at least 35 hot flashes and night sweats per week, were followed for 12 months. They kept diaries to record the number of hot flashes per day as well as the intensity.
The researchers found that the average number of hot flashes per week decreased over time across all groups — black cohosh decreased 34 percent, red clover 57 percent, placebo 63 percent and hormone therapy 94 percent.
“The important message is that all women improved, but there was a large placebo effect, and the botanicals did not work significantly better than placebo,” said Stacie Geller, the G. William Arends Professor of Obstetrics and Gynecology at UIC and lead author of the study.
“As expected, hormone therapy, considered the gold standard, significantly reduced hot flashes when compared with placebo,” Geller said.
“We also found that the botanicals were safe — which is important, since many women will still continue to use them.”
Geller and colleagues from the UIC/National Institutes of Health Center for Botanical Dietary Supplements Center reported no significant differences between botanical treatments and placebo for any of the safety parameters, including breast and endometrial safety, liver enzymes, complete blood count, or lipid profiles.
In a second study, UIC and Northwestern researchers enrolled 66 women from the parent trial to determine whether the botanic treatments had an effect on cognitive abilities, particularly verbal memory. It is the first study to evaluate the cognitive effects of black cohosh.
The women completed baseline cognitive testing before receiving treatment and again during the 12-month treatment to measure the recollection of words and short stories. They also wore monitors that measured changes in skin conductance during a hot flash. Both subjective and objective hot flashes were recorded during a 24-hour period.
The study, like the main trial, found that none of the botanicals had either a beneficial or a detrimental effect on memory. The specific hormone therapy used in the trial, Prempro, had a slight negative impact on memory.
“Together, these two studies demonstrate that compared to botanicals, only hormone therapy had a beneficial effect on vasomotor symptoms, but this benefit was at the cost of a slight decrease in memory,” said Pauline Maki, UIC associate professor of psychiatry and psychology and lead author of the cognition study.
The focus of ongoing research at UIC, Maki said, is to identify a safe and effective treatment for hot flashes that is either neutral or beneficial to memory functioning.