Intrigued by the physiological effects of black cohosh and its phytoestrogen agents, a number of researchers have recently set out to examine its impact on various human breast cancer cell lines. The assumption by many investigators was that black cohosh would encourage the growth of breast cancer cells, because its weak estrogenic effect was likely to promote proliferation of these cells. However, studies have demonstrated the opposite: Black cohosh has been shown to have an anti-proliferative effect on a number of human breast cancer cell lines. Essentially, black cohosh extract has prevented breast cancer cells from dividing in all of the in vitro studies reported to date. In one study, black cohosh was shown to increase the effectiveness of the breast cancer drug Tamoxifen, when both were used concurrently.
In the study by Foster, the authors concluded that extracts of black cohosh can be taken safely by patients who are susceptible to breast cancer (and possibly should be used as a means of chemoprevention). In reference to these studies, D. Dixon-Shanes and N. Shaikh remark in the journal Oncology Report (Nov.-Dec., 1999) that herbs such as black cohosh and soy isoflavones show potential as natural agents that may reduce the risk of breast cancer (if taken). As one in nine women in the U.S. develops this disease, it may be prudent for North American women to take a supplement containing black cohosh and soy isoflavones throughout adult life (unless contraindications are present) to discourage the promotion of breast cancer. If black cohosh and soy isoflavones can inhibit the proliferation of breast cancer cells, then in theory, this would give the immune system a better chance to destroy cancer cells before they have an opportunity to thrive.
The standardized grade of black cohosh extract that demonstrated clinical efficacy provided 2.5 percent triterpene content. A usual daily dosage for menopause is 40 or 80 mg, twice per day. Half this dosage may be prudent simply to support reproductive health throughout the premenopausal years, and as a primary intervention to potentially aid in risk reduction of breast cancer. Further studies are underway to enhance our understanding of this important and timely subject.
- Black cohosh: Safe for menopause. Herb Quarterly Dec. 21, 1999;84:7-8. Long Mountain Press, Inc.
- Dixon-Shanies D, Shaikh N. Growth inhibition of human breast cancer cells by herbs and phytoestrogens. Oncol Rep 1999 Nov-Dec;6(6):1383-7.
- Ainsworth C. The holistic herbal approach to primary dysmenorrhea (painful periods). Canadian Journal of Herbalism 2001;22(1):2-9,38-40.
- Black cohosh for hot flashes? Consumer Reports on Health Oct 2001;13(10):6.
- McKenna DJ, Jones K, Humphrey S, Hughes K. Black cohosh: Efficacy, safety, and use in clinical and preclinical Applications. Alternative Therapies in Health & Medicine May 5, 2001;7(3):93-100.
Vitamin C Supplementation Linked to Prevention and Treatment of Cataracts
Researchers from Tufts University extracted pertinent dietary, lifestyle and supplementation practices and performed cataract screening assessment on 492 nondiabetic participants from 1980 to 1995. The results, published in the American Journal of Clinical Nutrition, found that 34 percent of the group had cataracts (cortical opacities). A review of the data indicated a significant link between age and vitamin C intake for a very common form of cataracts, known as cortical cataracts.
For women younger than 60, a vitamin C intake greater than 362 mg/day reduced risk of cataracts by 57 percent, compared with those who had an intake of less than 140 mg/day. Those who took vitamin C supplements for more that 10 years had a 60-percent reduction in risk compared to nonsupplement users. Researchers also found that women who never smoked and had high intakes of folate and carotenoids showed a reduction in cataracts.
Dr. Ronald Plotnik, an associate professor of ophthalmology at the University of Rochester, N.Y., was quoted as stating, "I think it makes sense that vitamin C and other antioxidants might have a protective effect in terms of cataracts." He said that previous research suggests that free radicals (from UV light exposure and smoking cigarettes) could contribute to the development of cataracts.
The February 2002 Ophthalmic Epidemiology published the findings of the Roche European American Cataract Trial (REACT). This randomized clinical trial investigated the efficacy of an oral antioxidant, micronutrient mixture to slow progression of age-related cataracts. After three years, the subjects taking the vitamin mixture (18 mg beta-carotene, 750 mg vitamin C, and 600 IU of vitamin E) demonstrated a small but significant deceleration in the progression of age-related cataracts. There were no reported adverse side effects in the treatment group.
Together, these results imply that antioxidant vitamin supplementation, at moderate doses, is a safe and effective means to potentially prevent cataract development, and should be considered therapeutically to help slow the progression of existing age-related cortical opacities.
- United Press International, Boston, Feb. 22, 2002.
- Chylack LT, et al. The Roche European American Cataract Trial (REACT). Ophthalmic Epidemiol 2002; 9(1):49-80.
Soy Isoflavone Supplementation Demonstrates Ability to Reduce Bone Loss in Perimenopausal Women
There has been much debate if soy isoflavones, which act as weak estrogens in the body, have sufficient estrogenic activity to help prevent demineralization of bone when a woman's own estrogen production declines during menopause. Estrogen helps to keep calcium in bone until the menopausal years, when the drop-off in estrogen production is known to contribute to postmenopausal osteoporosis. In the U.S., one in four women demonstrates osteoporosis early in the postmenopausal years.
In a randomized study involving 69 perimenopausal women, the group that received 24 weeks of continual isoflavone-rich soy supplementation demonstrated a favorable effect on preventing bone loss versus the control groups, which were given either whey protein supplementation or isoflavone-poor soy supplementation (containing only 4.4 mg of isoflavones per day). This study convincingly demonstrated that a daily soy intake yielding 80.4 mg of isoflavones provides an estrogenic effect on bone, sufficient to slow or prevent its demineralization.
Larger studies of this type are necessary to confirm these findings. However, results from this preliminary trial agree with epidemiological evidence and animal studies: All indicate that soy isoflavones support bone mineral density in postmenopausal women and oopherectomized animals. Soy isoflavones studied most intensively for their phytoestrogen properties include genistein and diadzein.
- Alekel DL, et al. Isoflavone-rich soy protein isolate attenuates bone loss in the lumbar spine of perimenopausal women. Am J Clin Nutr 2000;72:844-852.
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