Cultivated around the world, the soybean is a miracle food – and inexpensive and nutrient-packed source of protein. Soy-based foods are a staple in many Asian diets, and researchers believe that is part of the reason why people in these countries often enjoy significantly lower rates of heart disease and breast, prostate, and colon cancer. Soy may also protect against osteoporosis.
Soy contains proteins and plant estrogens that benefit the heart and boost resistance to cancer. In a landmark 1995 analysis, researchers culled results from 38 different studies and found that in most studies of people with high cholesterol, adding soy to the diet lowered potentially harmful LDL cholesterol by 13 percent while leaving levels of beneficial HDL unchanged. On average, eating 25 grams of soy protein each day lowered cholesterol by 9 points. Although people with normal or borderline cholesterol (under 200 or so) don’t get the same cholesterol reduction from soy, they achieve other health-related benefits when they use it to replace artery-clogging animal protein in meals.
In addition to protein, soy contains plant estrogens (isoflavones). Like human estrogen, isoflavones inhibit bone loss and thus may help prevent osteoporosis. They may also fight cancer. Soy’s main isoflavone, genistein, suppresses proteins that protect cancer cells from the immune system. That allows the body to more easily destroy errant cells.
To benefit from this mostly low-fat, cholesterol-free protein source, eat three to seven servings of soy products a week. To lower elevated cholesterol, you’ll need about half a cup of tofu, two to three cups of soy milk, or 1 ounce (28 grams) of soy protein powder a day.
The best sources of soy protein are made by water extraction. Alcohol extraction, used for such products as meat or cheese substitutes, strips the beneficial isoflavones away. Check the labels carefully: If a product says "soy protein concentrate," it is made by alcohol extraction; you’ll still get the soy protein but not the protective plant estrogens.
It’s easy to use soy in recipes. Toss textured soy protein instead of ground meat into pasta sauces and chili. Tofu (soybean curd) makes a tasty stir-fry and substitutes well in recipes for cream cheese. Miso (fermented soybean paste) makes a good soup base. Grill tempeh (fermented soybean cakes) like burgers, pour soy milk on your cereal, and sprinkle soy powder into smoothies to add richness.
With so many health benefits to recommend it, soy deserves a place in your shopping cart. Soybeans (dried, canned, and frozen), sprouts, soy milk, soy protein powder, miso, tofu, tempeh, and soy flour are available at many grocery stores.