Midlife and Menopause
Natural Products: Phytoestrogens and Bioidentical Hormones
Since the release of the findings of the Women’s Health Initiative, many companies have taken advantage of the climate of fear surrounding hormone treatment to sell alternative products based on the unproven idea that other forms of estrogen will be safer than the synthetic hormones that were studied in the trial. This idea is based more on the principles of marketing than the principles of science. It's very important to remember that products are not necessarily safe just because they're called “natural.” The same questions we ask about drugs need to be answered for any alternative therapy too. What is the specific reason to take it? Are there well-designed, sufficiently large randomized trials showing that it is effective for the recommended purpose? What are the risks and harms associated with it? Has it been recommended to you by someone who may earn money from its sales?
Phytoestrogens are estrogens in plants. Some women eat specific foods that contain phytoestrogens to get the estrogenic effects. The food most commonly known to contain phytoestrogen is soy, but beans, peas, lentils, and whole grains and seeds, especially flaxseed, rye, and millet, also contain these plant estrogens.
We have relatively little evidence to support claims for the effectiveness of phytoestrogens and even less information about their safety. Alternatives like these are much less likely to be studied in formal research trials than drugs are, but there is some data from both observational and randomized controlled trials. Some studies have shown that eating foods with phytoestrogens provides modest relief of hot flashes,1 and some studies have found that eating phytoestrogens causes changes in vaginal cells that are similar to the changes caused by taking estrogen and could relieve discomfort. 2
When it comes to safety, there’s even less research to guide us. Women who eat foods containing phytoestrogens may be reassured by the knowledge that people have been eating foods containing phytoestrogens for thousands of years. But the health effects of consuming nonfood phytoestrogens, by taking the phytoestrogen dietary supplements that are now being produced and marketed to women, are not known.
Natural or Bioidentical Estrogen and Progesterone
The kinds of estrogens that we have in our bodies are estriol, estradiol, and estrone. The products that people refer to as “natural” estrogens also contain these hormones. The use of the word “natural” is confusing. Sometimes the term is used because the hormone is plant-derived, but it is misleading to describe these hormone products as natural, because they are synthesized in a laboratory just like the drugs that are called “synthetic” hormones. The real difference is that so-called natural hormones are chemically identical to the estrogens produced in a woman’s body, so some people use the term “bioidentical hormones” instead. The terms “natural” and “bioidentical” often are used to describe the same hormones, but “bioidentical” is the more precise name.
The compounding pharmacies that fill prescriptions for bioidentical hormones purchase the hormones that they use from major pharmaceutical companies, and those companies use the same hormones in their own standard drug products. Estradiol, for example, is contained in many pharmaceutical versions of hormone treatment. This means that women who are seeking natural alternatives because they want to avoid the hormones in the drug companies’ versions of hormone treatment are in fact using many of the same products when they take so-called natural hormones.
There haven’t been large research studies on bioidentical estrogens, but the studies that have been done have shown that they are effective for relieving hot flashes and vaginal dryness.3 Some alternative medicine proponents claim that they can prevent cardiovascular disease, but there is no valid evidence to support this assertion. There is research, however, showing that bioidentical estrogen may increase the risk of breast cancer, although the evidence is not conclusive.4 And recent studies have shown that estriol increases the risk of endometrial cancer and the abnormal growth of uterine cells, which can lead to cancer. 5
Bioidentical progesterone, including micronized progesterone, comes in creams and an under-the-tongue form as well as pills. It is promoted to prevent hot flashes, osteoporosis, and even breast cancer, but the only claim that’s supported by evidence is that it relieves hot flashes.6 The cancer prevention claims are unsupported, and even dangerous. While the oral progestins included in combination estrogen plus progestin hormone treatment protect against endometrial cancer, bioidentical progesterone cream is not well enough absorbed to offer this protection.7 We also don’t know the effect of bioidentical progesterone on risk of breast cancer, but the oral progestin in hormone treatment has been shown to increase breast cancer risk. In the absence of safety data showing that the risks are different, women are probably best served by assuming that the potential harms of bioidentical hormones will be similar to those of conventional hormone treatments.
Regulation of Compounding Pharmacies
Current regulations for the compounding pharmacies that prepare and distribute bioidentical hormones were developed when these companies were small businesses, working with a few health care providers in their communities and serving very few consumers. Today, compounding pharmacies represent a significant and growing industry, and some women’s health advocates have pointed out that the old regulations are no longer adequate to protect consumers.
In the fall of 2005, the National Women’s Health Network (NWHN) wrote to the FDA documenting significant problems with the way that compounding pharmacies promote and sell compounded hormones, which are often also marketed as bioidentical hormones. The NWHN is a nonprofit public interest group in Washington, D.C., that does not accept any funding from pharmaceutical or medical device companies. It asserted that women are being misled by unfounded and deceptive safety and efficacy claims about compounded hormones that have not been proven effective or studied for long-term safety. Concerned that the lack of FDA regulation over compounding pharmacies is exposing women to unsafe and ineffective products, the NWHN urged the agency to take steps to make sure that the labels and marketing materials for hormones dispensed by these facilities include the full and accurate information that women need to be able to make an informed decision.
Wyeth, the leading U.S. manufacturer of synthetic hormone treatment, has also written to the FDA. It argued that compounding pharmacies should be subject to the same regulation and oversight as drug companies that sell hormone treatment products. As of spring 2006, both the NWHN and Wyeth were still awaiting FDA action.
For more information, see
End of excerpt
Excerpted from Chapter 7: Hormone Treatment in Our Bodies, Ourselves: Menopause © 2006 Boston Women's Health Book Collective
1. Paola Albertazzi, Francesco Pansini, Gloria Bonaccorsi, Laura Zanotti, Elena Forini and Domenico De Aloysio, “The Effect of Dietary Soy Supplementation on Hot Flushes,” Obstetrics and Gynecology 91 (January 1998): 6-11; A. Brezinski, H. Adlercreutz, R Shaoul, et al., “Short-Term Effects of Phytoestrogen-Rich Diet on Postmenopausal Women,” Menopause 4, no. 2 (1997): 89-94; A. L. Murkies, C. Lombard, B. J. G. Strauss, G. Wilcox, H. G. Burger and M. S. Morton, “Dietary Flour Supplementation Decreases Postmenopausal Hot Flushes: Effect of Soy and Wheat,” Maturitas 21, no. 3 (April 1995): 189-195. [back to text]
2. F.S. Dalais, G.E. Rice, M.L. Dahlquist, M. Grehan, A.L. Murkies, G. Medley, R. Ayton, and B.J.B. Strauss, “Effects of Dietary Phytoestrogens in Postmenopausal Women,” Climacteric 1 (1998): 124-129; G. Wilcox, M.L. Wahlquist, H.G. Burger, and G. Medley, “Oestrogenic Effects of Plant Foods in Postmenopausal Women,” British Medical Journal 301 (1990): 905-906. [back to text]
3. Seth Granberg, Pekka Ylöstalo, Matts Wikland, and Bengt Karlsson, “Endometrial Sonographic And Histologic Findings In Women With And Without Hormonal Replacement Therapy Suffering From Postmenopausal Bleeding,” Maturitas 27, no. 1, (May 1997): 35-40; Elisabete Weiderpass, John A Baron, Hans-Olov Adami, Cecilia Magnusson, Anders Lindgren, Reinhold Bergström, Nestor Correia and Ingemar Persson, “Low-potency Oestrogen and Risk of Endometrial Cancer: a Case-control Study,” Lancet 353, no. 9167, (May 1999): 1824-28. [back to text]
4. Helene B. Leonetti, Santo Longo, and James N. Anasti, “Transdermal Progesterone Cream for Vasomotor Symptoms and Postmenopausal Bone Loss,” Obstetrics & Gynecology 94, no. 2, (August 1999): 225-228. [back to text]
5. Seth Granberg, Pekka Ylöstalo, Matts Wikland, and Bengt Karlsson, “Endometrial Sonographic and Histologic Findings in Women with and without Hormonal Replacement Therapy Suffering from Postmenopausal Bleeding,” Maturitas 27, no. 1, (May 1997): 35-40; Elisabete Weiderpass, John A Baron, Hans-Olov Adami, Cecilia Magnusson, Anders Lindgren, Reinhold Bergström, Nestor Correia and Ingemar Persson, “Low-potency Oestrogen and Risk of Endometrial Cancer: A Case-Control Study,” Lancet 353, no. 9167, (May 1999): 1824-28. [back to text]
6. Helene B. Leonetti, Santo Longo, and James N. Anasti, “Transdermal Progesterone Cream For Vasomotor Symptoms And Postmenopausal Bone Loss,” Obstetrics & Gynecology 94, no. 2, (August 1999): 225-228. [back to text]
7. A. Cooper, C. Spencer, M.I. Whitehead et al., “Systemic Absorption of Progesterone from Progest Cream in Postmenopausal Women,” Lancet, 351 (1998): 1255-1256. [back to text]
Excerpted from Our Bodies, Ourselves: Menopause, © 2006, Boston Women's Health Book Collective.
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