The Healing Power of Soy's Isoflavones
by Monique N. Gilbert
Numerous reports indicate that, because soy is high in isoflavones, it can prevent illness and promote good health. Isoflavones are a class of phytochemicals, which are compounds found only in plants (phyto means plant). They are also a type of phytoestrogen, or plant hormone, that resembles human estrogen in chemical structure yet is weaker. By mimicking human estrogen at certain sites in the body, isoflavones provide many health benefits that help you to avoid disease. Isoflavones are found in soybeans, chick peas and other legumes. However, soybeans are unique because they have the highest concentration of these powerful compounds. Soy contains many individual isoflavones, but the most beneficial are genistein and daidzein.
Isoflavones show tremendous potential to fight disease on several fronts. They have been shown to help prevent the buildup of arterial plaque, which reduces the risk of coronary heart disease and stroke. Isoflavones may help reduce breast cancer by blocking the cancer-causing effects of human estrogen. They may also prevent prostate cancer by hindering cell growth. Isoflavones can fight osteoporosis by stimulating bone formation and inhibiting bone resorption. They may even relieve some menopausal symptoms as well.
Soy isoflavones have antioxidant properties which protect the cardiovascular system from oxidation of LDL (the bad) cholesterol. Oxidized LDL cholesterol accumulates in the arteries as patches of fatty buildup which block the flow of blood, resulting in atherosclerosis. Genistein inhibits the growth of cells that form this artery-clogging plaque. Arteries damaged by atherosclerosis usually form blood clots. This can lead to a heart attack if the clot goes to the heart, or a stroke if it goes to the brain.
Being a weak form of estrogen, isoflavones can compete at estrogen receptor sites, blocking the stronger version naturally produced by the body from exerting its full effect. Since high blood levels of estrogen are an established risk factor for breast cancer; weaker forms of estrogen may provide protection against this disease. Genistein has been found to hinder breast cancer as well as prostate cancer. Results from a new University of California study show that genistein slowed prostate cancer growth and caused prostate cancer cells to die. It acts against cancer cells in a way similar to many common cancer-treating drugs.
Isoflavones also play an important role in protecting and maintaining strong and healthy bones. Evidence shows that genistein and daidzein prevent bones from breaking down. Independent studies conducted at the University of Illinois and the University of Hong Kong concluded that consuming soy isoflavones can increase bone mineral content and bone density. Another study at the University of Texas suggested that isoflavones may also stimulate bone formation. By preserving bone health, increasing bone mass and inducing bone turnover, researchers noted the potential role of soy isoflavones in preventing, and possibly even reversing, the effects of osteoporosis.
The North American Menopause Society suggests that soy isoflavones can also be a natural alternative to estrogen replacement therapy for relief of mild menopausal symptoms. They may help offset the drop in estrogen and regulate its fluctuations that occur at menopause. Many women have reported a reduction in their hot flashes and night sweats when they regularly consume soy foods, like tempeh or tofu.
All these findings suggest that eating soy foods, natural sources of isoflavones, can protect and enhance your overall health. Isoflavones work together with soy protein in fighting disease. Studies show that isoflavones account for approximately three-fourths of soy's protection, while its protein is responsible for about one-fourth. The best way to consume isoflavones is in food form, so that you can benefit from all of soy's nutrients and beneficial compounds. The highest amounts of isoflavones and soy protein are found in tempeh, whole soybeans (like edamame), textured soy protein, soynuts, tofu and soymilk. Researchers recommend consuming at least one to two servings a day. A serving is equal to 1 ounce of soynuts; 4 ounces of tempeh, textured soy protein (cooked), or edamame; or 8 ounces of soymilk.
For those new to soy, I recommend slowly adding it to your diet, until you develop a taste for it. In spaghetti sauces, replace ground beef with textured soy protein. Use tofu instead ricotta cheese in lasagna, or make herb dips with it in a food processor. Use soymilk to cream soups or make smoothies. People on the run can always eat soynuts. Tempeh is one of the easiest soy foods prepare: To make a grilled tempeh sandwich, just cut it into slices, sprinkle on some soy sauce, sauté with sliced onions and pile it on some bread. Remember, you will only continue to eat healthy foods if they taste good. So, experiment and have fun trying out new ways to enjoy soy.
Copyright © 2001 Monique N. Gilbert, All Rights Reserved.
Monique N. Gilbert, B.Sc., is a Health Advocate, Certified Personal Trainer/Fitness Counselor, Recipe Developer, Soy Food Connoisseur and author of "Virtues of Soy: A Practical Health Guide and Cookbook" (Universal Publishers, $19.95, available at most Internet booksellers).