The Joy of Soy
By Jason Cheng, DO
Tofu, soymilk. Miso soup, soy nuts and bean sprouts, these are the staple foods that is integral to most Asian diets has been largely responsible for many of the health benefits that we have come to associate with Asian women and men: less breast cancer, less heart disease, easier transition through menopause, and lower rates of obesity and diabetes. With the recent concerns of hormone replacement therapy swimming through the media and the medical establishment, one of the top questions many women have on their mind is what alternatives are available. My herb dictionary discusses some of the popular herbs and vitamins that are utilized either with or without hormone replacement, however natural plant derived estrogens from foods such as soy have merited special attention.
Does Soy Include Estrogen?
Yes and no. Soy does not contain estradiol, the form of estrogen that the body uses, but contains a sterol or cholesterol-derived chemical called an isoflavone, which leads to estrogen and estradiol formation in the body. It is isoflavone found in the foods of soy products that contribute to the estrogen-like benefits.
What are some benefits of soy isoflavones that are now being studied?
Control of Hot Flashes: Menopausal symptoms such as hot flashes, headaches, and fatigue have shown enormous improvements with regular soy diet. For instance, women from Asian countries with a traditionally high soy-based diet are known for having less hot flashes, fatigue and headaches. Whereas Asian diets usually comprise of up to 30-40 mg of soy a day, the American diet comprises of less than 2 mg.
Relieve Vaginal Inadequacies: Vaginal dryness and thinning are common complaints for women as they age with estrogen diminishing through time. However, soy isoflavones help to increase the perimenopausal state of the vaginal mucosa, thus diminishing vaginal dryness and atrophy.
Breast Cancer Prevention: One of the reasons why soy isoflavones may help prevent breast cancer is that it may prevent toxic estrogen metabolites from forming. Estrogen in itself may break down in the breast and form toxic substances; however, certain studies are revealing that soy isoflavones are metabolized differently, thus either bypassing the toxic phase of most estrogen hormones, or even “cleaning up” the toxic estrogen metabolites from the system. This information is highly speculative, but there is much research into why soy may be a large reason why the incidence of breast cancer is so much lower in Asian countries.
Lowers cholesterol and risk of heart disease: Cholesterol is normally seen as being contributive to heart disease and hypertension. However, there are two types of cholesterol molecules, or lipids. First there is the LDL, or low-density lipids that are “lousy”. Soy has been shown in studies to lower this type of bad cholesterol. However, there is also HDL, or hi-density lipids, which are the “happy” cholesterol molecules, and in addition to exercise, soy has been shown to increase this.
Prevention of Osteoporosis: A recent study done by the Journal of Clinical Nutrition in 2000 has revealed that postmenopausal females who had lower back osteoporosis diagnosis showed an improvement in bone strength as compared to the group that didn’t. Though this too is a newly researched area, there is possibility that more studies will come out discussing some of the bone benefits that soy may provide.
What are good sources of soy?
Here is a list of some popular foods that are rich in soy:
· Soybeans: As a stand-alone food, soybeans and soy sprouts are either eaten whole, boiled, or stir-fried.
· Miso: The fermented bean paste is used as a base for this popular soup and sauce in Japanese cuisine.
· Soymilk: This milk substitute is made from cooked soybeans, and is both nutritious and sweet. Almost all supermarkets have soymilk on the shelves right next to regular milk and dairy products.
· Tofu: Whether raw, baked, pressed, fermented, boiled or stir-fried, this bean curd is the staple of many Chinese, Korean, and Japanese meals. A common way of adding this to a daily American diet is to add it to salads and soups.
What about other forms of soy like pills, supplements or soy bars?
It is uncertain how effective the ingredients in soy and other legumes are if they are taken out of their natural form as food. Although we’ve discovered much about the benefits of isoflavones, we don’t know if they are as effective when they are artificially repackaged. Because there is still little evidence for the efficacy of soy supplementation through pills or supplements, organizations including the National Women’s Health Network discourage the use of these additives. Remember, when at all possible, eat whole foods, or come up with ways of adding them to your favorite foods.
Is soy only beneficial to menopausal women?
Though most of the attention of soy recently has been primarily for women, there are studies out that show a decrease of prostate problems for men when soy is consumed in the diet. Also, soy may prove to have a particular dramatic effect in pre-pubertal, and pubertal girls, since this is the period in which estrogen receptors become active. It is especially important to incorporate a healthy high fiber and soy-supplemented diet during these crucial years of development. There is strong evidence that our reliance on fattening fast-food diets, particularly with the now industrializing Asian cities, are responsible for the increased incidence of various cancers that our now a major worldwide health problem. As Asian cultures adopt western styles of clothing, music, and food, it seems as though they have also adopted some of our public health concerns too. We may all have something to learn about the value of a traditional Asian diet. Perhaps McDonald’s will show some social responsibility by offering the McSoy meal!
In the meantime, remember that soy should not be thought of as replacement for your medical treatment. However, I strongly advocate the incorporation of soy, flaxseed, beans, rye, and whole wheat into our daily diet. One thing that is becoming apparent is the importance of adopting healthy eating early on in your development. Conditions that afflict women in this country such as heart disease, endometrial and breast cancers, as well as osteoporosis may be prevented or postponed with soy included in the daily diet. So adopt healthy habits for you and your whole family early on while you learn about the many joys of soy.
