Isoflavones, found abundantly in soy products, reportedly have many health benefits, including protection against breast and prostate cancer, menopausal symptoms, heart disease and osteoporosis. However, much controversy surrounds consumption of high levels of isoflavones, as the efficacy and safety of soy isoflavones have not yet been established. Particularly of interest and concern is the fact that the chemical composition of isoflavones is similar to estrogen, and isoflavones have estrogenic activity. That said, according to the American Heart Association, foods that contain isoflavones are beneficial as they are high in polyunsaturated fat, fiber, vitamins and minerals, and provide for increased intake of dietary protein, while decreasing dangerous saturated fats and unnecessary carbohydrate intake from consumption of empty calories.
Isoflavones, powerful phytoestrogen chemicals found in soy plants that work like estrogen in the human body, are most prevalent in soy foods than in any other foods. Recognized for their potential health benefits, soy proteins, or soy nuts, contain the most isoflavones of any food. According to the Linus Pauling Institute, "diets rich in soy or soy-containing products appear safe and potentially beneficial," and just 3.5 ounces of soy protein contain 102 milligrams of isoflavones. Although there are no daily intake requirements for isoflavones established to date, the National Institutes of Health recommends a minimum of 25 grams of soy protein per day to prevent heart disease. Plain or salted, soy nuts make a great snack, and can be used in salads or other dishes.
Miso is a Japanese mixture of fermented cooked rice, barley, soybeans and salt that makes a savory sauce, spread or soup. Just a 1/2-cup serving of miso has 59 milligrams of isoflavones, second only to soy nuts. Miso is a staple food in Japanese culture. As a spread, miso may be used with pitas or crackers, or even fresh vegetables. Miso is a soup thickener or base, and provides added nutrition and flavor. In Japan and China, intake of isoflavones far exceeds that in the U.S.; they consume 25 milligrams to 50 milligrams per day, while in the U.S., isoflavone consumption is just 2 milligrams per day.
Edamame and Other Soy Products
Boiled soy beans are also a plentiful source of isoflavones, as a 1/2-cup portion provides 47 milligrams of isoflavones. Easy to prepare, boiled soy beans, or edamame, can be served at any meal or for a snack. Other foods rich in isoflavones and soy protein include tofu, easily used in vegetable stir-fry and soup; soy butter, for spreading on pita and bread; and soy burgers for grilling.