In Asian countries, soy products are an everyday staple. The Japanese, who eat about 24 pounds of soy food per person per year (Americans eat about 4 pounds), live longer than people anywhere else in the world and have the lowest rates of heart disease. Although no one can say for sure that soy plays a role in these statistics, there's strong evidence in its favor.

A 3-ounce serving of tofu provides 20 grams of protein, along with about half the RDA for bone-building calcium and 13 milligrams of iron -- that's 87 percent of the RDA for women and 130 percent of the RDA for men. The high iron content in soy foods is absorbed well, unlike that in most plant foods. And although tofu and other soy foods are moderately high in fat, most of the fat is polyunsaturated. All these factors make soy a terrific meat replacer.

Even if you already eat a low-fat diet, you can substantially lower your blood cholesterol by replacing some low-fat animal protein with soy products. Studies have shown that people with raised blood cholesterol levels who ate soy products instead of half or all of the animal protein in their diet, reduced their blood cholesterol by 8 to 16 percent in a few weeks. Researchers attribute this to the particular balance of fiber, fatty acids, and phytoestrogens in soybeans, which help deactivate and remove dangerous LDL cholesterol from the body. Soybeans also contain alpha-linolenic acid, an omega-3 fatty acid linked to improved heart health.

Soybeans, tofu, tempeh, and other soy products are rich in both soluble and insoluble fibers. Soy fiber improves digestion and can prevent and ease constipation, thereby reducing the risk of colon cancer and other bowel diseases.

Soy fiber also helps regulate blood sugar levels. By slowing down the speed of digestion and absorption, fiber fosters a steadier rise and fall of blood sugar, which benefits diabetics and stabilizes energy levels.

Early evidence shows that eating soy products reduces hot flashes and other symptoms of menopause and postmenopause, such as loss of bone minerals. Researchers believe this is due to soybeans' high phytoestrogen content.

Soybeans are the richest known source of the phytoestrogen compounds genistein and daidzein, which are weaker versions of the estrogen women produce naturally. When estrogen rises to dangerous levels in the body, phytoestrogens may supplant some of it in the body, helping to return it to normal, safe levels.

Soy has such beneficial effects that researchers foresee a day when it will replace or supplement estrogen replacement therapy.

The phytoestrogens in soy have also been linked to reduced rates of breast cancer. High estrogen levels are one risk factor for breast cancer; eating foods high in fiber and estrogen-supplanting phytoestrogens helps reduce blood estrogen. One study showed that premenopausal women who consumed high amounts of soy foods, along with beta-carotene and polyunsaturated fats, had only half as much risk of developing breast cancer as women who consumed high amounts of animal protein.

Soy may do wonders for men as well. A diet abundant in soy-rich foods seems to help reduce levels of the male hormone testosterone, which may spur the growth of cancerous cells in the prostate gland.

Raw soybeans, including soybean sprouts, contain a toxin that must be destroyed by thorough cooking before eating. Soak soybeans for at least five hours before cooking, then boil them in fresh water for at least two hours.

When cooking with tofu or other soy products, add them at the end of cooking time. Cooking soy products at high temperatures for extended periods may destroy some of the nutrients. Miso, soy sauce, and soybean oil lack the benefits of other soy products.

You're best off buying full-fat soy products, such as soy milk, because they contain much higher amounts of beneficial phytoestrogens.

Soy milk contains phytoestrogens but little fiber or calcium.

Many people think that if certain foods are good, a lot is better.
This is not always the case, and high doses of certain food are actually toxic.

Read about the healthy food, research the vitamins and minerals and check with your health care provider if you are unsure about how much to eat and how much may be too much.