What Are Phytoestrogens and Why Use Them?
Phytoestrogens are plant-derived chemicals which have weak estrogen-like activity. Many women who do not wish to take synthetic estrogens often take various phytoestrogens to alleviate menopausal symptoms, believing them to be safe because they are “natural.” It gets more complicated in women who have a diagnosis of cancer since some cancers are estrogen sensitive. So, what does this mean and are phytoestrogens safe?Estrogen Receptors in a Nutshell
In a nutshell, the effect of estrogen on cancer depends upon the presence or absence of receptors on the cell surface to which estrogen can attach to. Most physicians do not recommend that patients with estrogen sensitive cancers take estrogen for menopausal symptoms, for fear of causing or accelerating a recurrence. Research has focused on breast and uterine cancers. Although there is no clinical proof that ovarian cancer can be influenced the same way, theoretically the effects could be similar because ovarian tissue contains estrogen receptors. For this reason, most women either heed physicians’ advice or simply shy away from using synthetic estrogen after a breast, uterine or ovarian cancer diagnosis.More recent laboratory research has shown that there are different estrogen receptor subtypes. In general, activation of the alpha-estrogen receptor component can cause cancer cells to grow, while beta receptor stimulation has an anti-cancer effect. Synthetic estrogen can stimulate both receptor subtypes while plant estrogens (phytoestrogens), preferentially stimulate beta-estrogen receptors. Thus it appears that phytoestrogens might be safe to take, without increasing the risk of cancer or recurrence.
Phytoestrogen Types
Many herbal phytoestrogens are sold without prescription as natural menopausal aids. The most widely used phytoestrogen herbals in the United States are extracts of soy or red clover that contain isoflavones or black cohosh. However, while some studies have been promising, most clinical trials have failed to prove that these substances reliably help prevent menopausal symptoms.An extract of one type of rhubarb, also known as Rheum rhaponticum, has been used in Germany since 1993 and widely hailed as very effective. Over the past several years, well designed prospective placebo controlled clinical trials have shown that Rhubarb is effective in reducing anxiety as well as the number and severity of hot flashes.
Laboratory biochemical studies show that Rhubarb works by attaching to the cancer inhibiting beta-estrogen receptor. Based on this information, it is reasonable to discuss the use of Rhubarb with your doctor as a promising natural alternative to synthetic estrogens for managing menopausal symptoms, even if you have a history of cancer.
Ask Your Doctor About Phytoestrogens
If you consider this option, especially if you have or had cancer, never take any herbals without consulting your doctor or oncologist. Also, you might want to share some references in case your doctor is not aware of these research developments.Sources:
Kaszkin-Bettag M, et al. The special extract ERr 731 of the roots of Rheum rhaponticum decreases anxiety and improves health state and general well-being in perimenopausal women. Menopause. 2007 Mar-Apr;14(2):270-83.
Heger M, et al. Efficacy and safety of a special extract Rheum rhaponticum (ERr 731) in perimenopausal women with climacteric complaints: a 12-week randomized, double-blind, placebo controlled trial. Menopause. 2006 Sept-Oct;13(5):744-759.
Wober J, et al. Activation of estrogen receptor-β by special extract Rheum rhaponticum (ERr 731), its aglycones and structurally related compounds. J Steroid Biochem Mol Biol. 2007 Nov-Dec;107(3-5):191-201.
