Get the Scoop on Soy

Researchers are taking a close look at soy and its relationship to such diverse health issues as cancer, high cholesterol, and menopause. Soybeans, already known as an excellent source of protein, are the most widely used legumes in the world. In America, however, soy products have been largely ignored except as a cooking oil or milk substitute or as a hidden ingredient in margarine, pasta, cereals, and baby formula.

Public interest in tofu, soy burgers, and a wide variety of soy products is growing as people begin to understand how and why "it's good for you."

Cancer
In Japan, where soy is a major part of the diet, an attention-getting cancer statistic has been reported. The 4th Edition of Cancer Rates and Risks, edited by Harras, shows the prostate mortality rate to be five times lower than in the United States. Phytoestrogens or isoflavones, which are abundant in soy protein, may combat cancer in both men and women. Scientists are eager to learn more about these chemicals, which are similar to human hormones, only weaker.

Breast cancer is a hormonally-driven tumor and its growth is fueled by the hormone estrogen. All estrogens must actually attach to a receptor in order to work and when too much estrogen reaches the receptor, the risk of cancerous growth increases. Genestein, one of the isoflavones or pigments found in soybeans, has been seen to block the natural estrogen activity related to cancer growth in a manner similar to the breast cancer drug tamoxifen. Stephen Barnes, Ph.D., a professor of pharmacology at The University of Alabama at Birmingham, is one of the researchers who has reported on this beneficial effect of genestein.

Another recent study found that drinking soy milk more than once a day was associated with a 70 percent reduction in men's risk for prostate cancer. Soy estrogens may block testosterone, slowing prostate tumor growth.

Free Radical Activity
The phytoestrogens in soybeans work as antioxidants in combating free radical damage. Free radicals are unstable molecules that result normally in the metabolic process but that can become excessive due to environmental factors, stress or even too much strenuous exercise. Left with one missing electron, these free radicals can damage cell membranes and DNA as they scavenge to regain balance by taking an electron from another cell. Specific medical problems that can be linked to free radical activity include cancer, clogging of the arteries, strokes, cataracts, rheumatoid arthritis, and Parkinson's disease. Vitamins C, E, and beta carotene are the most commonly recommended antioxidants that will actually fill the space of the missing electron and help prevent health problems.

Cholesterol
Soy also helps regulate cholesterol. At the University of Kentucky, James Anderson reviewed 38 human studies in the New England Journal of Medicine, noting that subjects who substituted 47 grams of soy protein in place of animal protein lowered their "bad" LDL cholesterol by 13 percent, triglycerides by 10 percent, and actually raised their "good" HDL cholesterol by 2.5 percent.

Cardiovascular Health
The genestein in soy helps to keep platelets from clumping together and forming a clot that could result in a heart attack or stroke. The isoflavones, genestein and diadzein keep the LDL cholesterol from damaging artery walls and depositing cholesterol. Anderson's study concluded that regular consumption of soy protein could cut heart disease risk by 25-30 percent.

Hot Flashes
The estrogen-mimicking isoflavones in soy products also have been shown to significantly reduce the symptoms that often accompany menopause such as hot flashes and mood swings. One study of postmenopausal women showed regular use of soy flour reduced hot flashes up to 40 percent. Another study found that women who supplemented daily with 60 grams of soy protein isolate for 12 weeks experienced a 45 percent reduction in hot flashes.

Bone Density
Due to its estrogen-like behavior, soy may prevent the loss of bone calcium and keep bones strong later in life. A University of Illinois study of postmenopausal women discovered that those who ate 40 grams of soy protein isolate containing high levels of isoflavones increased bone mineral content and bone density in the lumbar spine.

People whose initial reaction is to shake their heads 'no' at the idea of eating tofu or tempeh can take comfort in the fact that there are many other ways of getting soy into your diet. And, many soy-enthusiasts have found creative ways to use tofu straight--there are entire cookbooks filled with healthy, appetizing recipes.

It takes 25 grams or more of soy protein a day to get the health benefits that have been discussed.

Isolated Soy Protein
Sold as powder under the label Genisoy or TakeCare Soy Protein Powder. Can be used in fruit smoothies, sauces, soups, to name a few. Provides 20-24 grams protein per oz.

Soy Flour
Replace regular flour with soy flour when baking. Only replace 25 percent of the regular flour when making bread because soy flour does not contain the gluten. Provides 20 grams protein per 1/2 cup

Soy Milk
Substitute for milk, but make sure that the product has been fortified with vitamin and minerals and has added calcium. Provides 7 grams protein per cup

Soy Nuts
Eat them plain for their nutty taste or add them to yogurt or salads. Provides 17 grams protein per 1/4 cup

Textured Soy Protein
After rehydrating with water or vegetable broth, it takes on a meat-like texture and can be used in casseroles, tacos, or spaghetti sauce. Provides 23 grams protein per 1/2 cup