Phytoestrogens

Phytoestrogens are hormone-like compounds found in all plants. They balance our hormones, support our immune systems, and prevent or ease the symptoms of menopause and osteoporosis.

Today's number one health concern for women is hormones. In light of recent evidence stacking the deck against hormone replacement therapy, women are looking for alternatives. This is evident in my practice, where female patients often ask me about the benefits of phytoestrogens, hormone-like compounds found in all plants in one form or another. They are one-fiftieth to one-twenty-thousandth weaker than the body's steroidal estrogens, which are made by the ovaries.

How do phytoestrogens work? They contain active chemical constituents such as isoflavones, coumestans and lignans, which work as hormone balancers; phytoestrogens both exert mild estrogenic effects themselves and compete with more potent steroidal and environmental estrogens (xenoestrogens) for "receptor binding sites" on cells. Imagine these receptor binding sites as parking spots reserved for hormones. Once "parked," the hormone can exert its effect on the cell. If the body's steroidal estrogen levels are low, phytoestrogens fill those parking spots and gently mimic the role played by steroidal estrogens. If the levels of steroidal or environmental estrogens in the body are too high, phytoestrogens block their access to estrogen receptor sites, substituting their own milder estrogenic activity for the excessively strong estrogenic effects created by overabundant steroidal or environmental estrogens.

In addition to their hormone-balancing activities, phytoestrogen compounds provide many other health-promoting benefits. Recent studies have documented that soy foods, which contain phytoestrogenic isoflavones, are antibacterial, antiviral, antifungal, antioxidant and anti-inflammatory. They also provide immune system support, prevent platelet aggregation (blood clotting), prevent or ease menopausal symptoms and both prevent and treat osteoporosis.

The American Heart Association states, "there is increasing evidence that the consumption of soy protein in place of animal protein lowers blood cholesterol levels and may provide other cardiovascular benefits" (Circulation 2000; 102: 2555). Further, the American Cancer Society recently revealed that breast cancer kills three times as many American women as Japanese women, and that colon and prostate cancer in Japan is significantly lower than in North America (National Dairy Council Nutrition Service Quarterly Review, Winter 1998; 21-23). It has been suggested that environmental factors, especially the diet, play an important role. The intake of phyto-estrogens in Japan, for example, is 30 times greater than in North America.

Dietary Strategy

There are many ways women can take advantage of the benefits of phytoestrogens. You can begin by eating more foods rich in these plant compounds. Something to keep in mind is that the absorption of phytoestrogens depends on a healthy gut. The gut must contain enough healthy bacteria capable of converting phyto-estrogens into their active forms: once absorbed, phytoestrogens are transported to the liver and most are removed from circulation. Some, however, enter the bloodstream and eventually bind to estrogen-receptor sites to exert their balancing effect as required. As you've probably already guessed, imbalances in intestinal microbes, such as yeasts and fungi, can interfere with the absorption process; in this case, I would recommend taking probiotic supplements (acidophilus or bifidus) to help rebuild healthy gut bacteria.

The Goods on Soy

Soy products have become the most popular source of phyto-estrogens in North America. Thousands of soy-based products are available in the marketplace. It should be noted, however, that the Asian diet typically contains fermented soy products. Naturally fermented soy comes in foods such as miso and tempeh or whole-bean fermented soy powders. Since phytoestrogens can exert mild estrogenic effects in higher doses, many researchers feel this is why women in cultures consuming predominantly plant-based diets rarely experience hot flashes and other menopause-related symptoms. And given that many of the world's cultures have been eating fermented soy bean products for thousands of years without ill effect, we can gather that using soy products to address menopausal symptoms is far safer than taking synthetic hormone replacement.

In pilot studies conducted by Dr. J. Eden and colleagues at the Royal Hospital for Women in New South Wales, Australia, it was found that when women were given 160 mg of isoflavones (found in soy) daily for three months, a significant reduction in several menopausal symptoms, especially hot flashes, occurred. Further studies have shown smaller decreases in menopausal symptoms with a daily consumption of 40 mg of isoflavones. Research by McMichael-Phillips et al. found that 60 grams of soy protein providing 45 mg of isoflavones had estrogenic effects.

All women should consider using phytoestrogenic foods in their diets. However, the jury is still out on whether phytoestrogenic plants are appropriate for women with breast or ovarian cancer. If you have or are at high risk for breast cancer, I would recommend using only food sources of phytoestrogens, such as fermented soy tempeh or miso, in moderation (less than 40 grams daily). Do not use concentrated, supplemental iso-flavone formulas or other highly concentrated soy products.

For many women seeking natural treatments for hormonal imbalances, a healthy diet based on legumes, vegetables and hormone-free animal products (animal products can be a source of unwanted xenoestrogens) is a good first step. For a more in-depth strategy, you may wish to consult a qualified health practitioner because hormonal health depends completely on the overall health of the individual on all levels physical, emotional, mental and spiritual.

Phytoestrogen Foods

Plant foods containing phytoestrogen constituents include legumes such as soy beans, lentils and chickpeas; vegetables such as fennel, celery, carrots, asparagus and parsley; grains such as oats, wheat and corn; and the herbs red clover, alfalfa, licorice and hops. These compounds have also been isolated in nuts and seeds, particularly flax, and are found in some quantity in sesame seeds, safflower and pumpkin oils. Legumes contain 23 to 230 milligrams of phytoestrogens per 100 grams; vegetables, one to 200 mg per 100 g.