phytoestrogens

Fifty-Plus Fitness Library

Phytoestrogens: A Hot Nutritional Topic

What Are They, and What Could They Do For You?

By Christopher Gardner, Ph.D.

Phytoestrogens (not fido-estrogens) literally means “plant” estrogens. They are found in a variety of plants, with soy and flax being particularly good sources. The evidence is beginning to accumulate that these plant estrogens confer powerful health benefits.

It is well recognized that, among women, rates of heart disease, osteoporosis, breast cancer, ovarian cancer, and other chronic diseases are notably lower in populations that typically consume large quantities of soy beans and soy products (e.g. tofu, tempeh, miso). This observation alone doesn’t prove anything, since soy contains other protective factors besides phytoestrogens that could explain the different disease rates. Or it could be that people who consume large amounts of soy are typically different than other people, e.g. genetically different, more physically active, or have healthier diets overall. On the other hand, the evidence for a biologically plausible connection is well on its way to being established.

Many laboratory scientists who work with animals and molecular science techniques have found that phytoestrogens can bind to estrogen receptors just as do natural estrogen hormones. These experiments have shown that the phytoestrogens can act similar to, but are much weaker than, the natural estrogens in a woman’s body. Based on this similarity, with weak activity, the following hypothesis has been generated regarding the potential health benefits of phytoestrogens in pre- and post-menopausal women. For pre-menopausal women, at a time in the life cycle when natural estrogen levels in the body are relatively high, phytoestrogens compete with estrogen for estrogen receptors, thereby blocking the effect of the natural hormone (anti-estrogenic effect). For post-menopausal women (with dramatically lower estrogen levels), there is so little natural estrogen available in the body that even the weakly estrogenic phytoestrogens provide a bit of an estrogenic boost.

Our present understanding of phytoestrogens is limited, but we do know there is great potential. There is some thought that these plant estrogens may provide an alternative to estrogen replacement therapy for post-menopausal women, or, may enable some women to cut back on their daily dose of estrogen. We will fill you in on how much we really know, and how much is speculation. And we will tell you about ways you can get phytoestrogens in your diet, with few known risks, and many potential benefits.

PHYTOESTROGEN STUDY FOR WOMEN

Post-menopausal women with moderately elevated levels of blood cholesterol (LDL-cholesterol > 130 mg/dL, screening provided free of charge) are encouraged to call and inquire about a study of phytoestrogens and women’s health. The Stanford Center for Research in Disease Prevention has been funded through the newly created Office of Complementary and Alternative Medicine (National Institutes of Health) to investigate the potential health benefits of dietary phytoestrogens, or plant estrogens. A tremendous surge of interest in these plant estrogens has developed as the evidence continues to accumulate for potential health benefits in the areas of cardiovascular disease, cancer, osteoporosis and menopausal symptoms.

We are looking for 180 women to join us by participating in the study. To be eligible for the study, participants must be at least 12 months post-menopausal, not on estrogen replacement therapy (or willing to discontinue), less than 80 years of age, and not taking medications to lower blood cholesterol. Participation will involve primarily the consumption of different dietary protein supplements that may or may not contain phytoestrogens; two prepackaged supplements must be consumed every day of the study. The duration of the study is 5 months. At the end of the time period, all participants will receive the results regarding their participation, which will include blood cholesterol measurements, any changes in natural hormone levels, and other clinical measures. There is no financial compensation for participation.