Up Close & Edible: Soybeans

Forget soy's reputation as a tasteless meat substitute for health nuts. Consumption of the high-protein legume has been rising ever since the Food and Drug Administration officially recognized it as a heart-healthy alternative in 1999. From 2001 to 2004, American food manufacturers introduced over 1,600 new foods with soy as an ingredient. In many supermarkets across the country, you can find soy drinks, various kinds of tofu, cultured soy, non-meat alternatives, frozen dairy-free soy treats, soy nuts, soy nut butter, and cereals and bars with soy. As a result, 30 percent of Americans now consume soy products at least once a month.

The FDA boosted soy's reputation after reviewing 50 studies; it then approved health claims that consuming 25 grams of soy per day will reduce the risk of coronary heart disease. Because soy protein can be added to such a wide variety of foods and beverages, the FDA suggests aiming for four servings a day. Soy foods also contain isoflavones, which may offer additional health benefits including lowered risks of certain cancers and cardiovascular disease. Soy may also help reduce the risk of osteoporosis, although more research is needed to confirm this.

One caveat for women who've been diagnosed with breast cancer: animal and lab studies of breast-cancer cells have indicated that soy may promote the growth of breast-cancer cells in some cases and inhibit it in others. Breast-cancer survivors don't have to avoid soy, but they should eat it in moderation until more is known about how it might affect them.

Besides isoflavones, soy has a high content of polyunsaturated fats, fiber, vitamins, minerals and a low content of saturated fat—which makes it an ideal substitute for less healthy foods. But like anything you eat, deep-frying soy foods like tofu (a favorite vegetarian dish) will increase saturated fats and cholesterol and largely negate the health benefits, so prepare your soy in the same heart-healthy way you would prepare anything else.