Many women experience the symptoms of menopause after their fourth decade and most of them find these symptoms to be a source of anxiety and discomfort. For more than half a century, a combination of estrogens and progestins, or Hormone Replacement therapy (HRT), has had beneficial effects on the symptoms of menopause and osteoporosis; however, recently published clinical studies have questioned the safety of this treatment for the cardiovascular system; furthermore, the increased risk of breast cancer has also been brought up. Therefore, there are attempts to find alternatives for HRT.
Ideally, the herbal drug that is to be used as an alternative for HRT should lack estrogenic effects on breast and uterine tissues, but have beneficial effects on menopause symptoms and on the bones. Herbal estrogens have no or little effect on menopause symptoms in low doses, and in higher doses mimic the effects of estrogen. Therefore, researchers aim for finding other herbal compounds.
Black cohosh rhizome extract does not bind to estrogen receptors and in in vitro has no estrogenic effects on breast cancer cells, breast tumors and uterine histology of ovariectomized rats. Furthermore, in this model of rat study, an extract of black cohosh called BNO 1055 prevented hot flashes and spread of osteoporosis. This extract reduces the symptoms of menopause in women as much as conjugated estrogen and considerably more than placebo. In all European studies, no trace of an effect on uterus or breast tumors was observed.
Most probably, the active ingredients in black cohosh extract have neurotransmitter mimicking properties: dopaminergic, noradrenergic, serotonergic and GABAergic effects have been demonstrated and the structures of some of them have also been identified. Researchers have concluded that the use of low doses of black cohosh extract is effective in alleviating menopause symptoms without having estrogenic side effects. These evidence are strongly in favor of black cohosh extract as an alternative for HRT.(1)
In in vitro, diosgenin, which is a saponin extracted from sweet potato, does not bind to human estrogen or progesterone receptors and cannot convert to progesterone in the body. Theoretically, sweet potato can be prescribed for women who have undergone treatment for breast cancer; however, more data is needed regarding its safety. When sweet potato was administered warm, its effect on menopause symptoms was not statistically significant compared to placebo. In ovariectomized rats, sweet potato increases bone density, but there is yet no human study in this field.
In a study on 22 women who consumed 390 g sweet potato daily for 30 days, it was observed that the urine concentration of 16-alpha-hydroxyestrone significantly decreased about 37%. This indicates the potential of sweet potato in decreasing breast cancer risk; however, more results are needed based on clinical trials.(2)
To study the effect of soybean isoflavone on menopause symptoms, in a double-blind, placebo-controlled study, 80 women with the average age of 55.1 years, with at least 5 hot flashes per day, randomly received 250 mg standardized soybean extract with 100 mg total isoflavone per day (n=40) or placebo (n=40). The menopause symptoms were monitored for 10 months using the Kupperman menopause index.
At the beginning of the study, the mean number of hot flashes was 9.6±3.9 in the soybean isoflavone group and 10.1±4.9 in the placebo group (p>0.05). After 10 months, there was a considerable decrease in the frequency of the hot flashes in the isoflavone group in comparison with the placebo group (5.4±4.3 and 3.1±2.3 respectively) (p<0.001). Both groups showed considerable reduction in Kupperman index. Still, soybean isoflavone was much more efficient than placebo in decreasing the intensity of the hot flashes (69.9% and 33.7% respectively) (p<0.001). Endometrium thickness, mammogram, vaginal cytology, lipid and hormonal profile showed no change in either of the groups. No adverse reaction related to isoflavone was reported. The researchers concluded that the extract containing isoflavone has desirable effects on the vasomotor symptoms of menopause and has good patient compliance and can be an effective and safe alternative treatment for women in menopause.(3)