Phytoestrogens: A Natural Hormone Replacement Therapy?
Interest in natural hormone replacement therapies is on the rise.
The reports that the lower incidence of breast cancer, hot flashes and other menopausal ailments in Asian women can be contributed to a diet rich in soy and tofu products increased the interest in dietary supplements containing phytoestrogens to treat menopausal symptoms.
Phytoestrogens are plant derived estrogen-like substances and can be divided in three main categories: lignans, isoflavones, and resorcyclic acid lactones.
Isoflavones can be found in chickpeas and soy products, Flaxsees or linseed are high in liganes, and resorcyclic acid can be found in grain products contaminated with certain fungi, especially Fusarum, which should not be part of your normal diet.
How do estrogens work and do we have evidence that it can prevent cardiovascular disease or osteoporosis?
Phytoestrogens are weak estrogens and are less than 1% potent as produced estrogens measured in blood testing. Phytoestrogens bind weakly to estrogen receptors and can produce estrogen-like responses.
It is of importance to emphasize that phytoestrogens can produce in adequate doses the same biological response as endogenous estrogen!
Several human studies have shown that appropriate dosage of phytoestrogen can reduce hot flashes in some women. Animal studies indicate that phytoestrogens may even reduce the risk of cardiovascular disease and osteoporosis but no prospective, randomized human studies are available yet!
It is of interest to note that phytoestrogens do not increase endometrial cancer rates (uterus cancer). Conjugated estrogens (e. Premarin etc.) can increase the rate of endometrial cancer if not combined with progesterone (e.g. Provera). Furthermore, it has been postulated that the low breast cancer rate among Asian women can be contributed to the estrogen-receptor blocking effect of plant derived estrogens on breast tissue.
How much phytoestrogen do you need to consume to reach equivalent effects?
In Asia the consumption of legumes (soybeans, lentils, and peas) provides 25-45 mg of total isoflavones a day. The soy consumption is especially high in Japan reaching up to 200mg daily.
In the US and other Western countries the average consumption is less than 5mg per day!
How to supplement your diet? Increase the intake low-fat soy products (cheese, milk), ad flaxseed oil and legumes to your diet.
Some companies even offer capsules containing isoflavones and other phytoestrogens. Unfortunately, we have no human studies on the long-term effect of those products and often these products contain other compounds (e.g. black cohosh), which should not be taken continuously.
At this point in time I can not recommend to endorse the substitution of traditional hormone replacement therapy with plant derived estrogen! No clinical data are available to support this assumption yet!
Nevertheless for the suppression of menopausal ailments (hot flashes, vaginal dryness) phytoestrogens are a proven supplement and be part of your diet.
Please contact a physician knowledgeable in herbal medicine prior to combining supplemental phytoestrogens with other prescription medications such as Tamoxifen, Raloxifen, Premarin, Provera etc.
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