The soybean has been a part of the human diet for almost 5,000 years. Unlike most plant foods, the soybean is high in protein and is considered equivalent to animal foods in terms of the quality of the protein it contains.

Soy in your diet can lower cholesterol. There are many scientific studies that support this conclusion. In fact, the U.S. Food and Drug Administration (FDA) agreed that 25 grams per day of soy protein, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.

Soy may also reduce symptoms of menopause and the risk of osteoporosis. Soy products may possibly prevent certain hormone-dependent cancers, including breast cancer, endometrial cancer, and prostate cancer.

Not all soy protein products contain the same amount of protein. The following list ranks some popular products from greatest amount of soy protein to lowest:

• Soy protein isolate (added to many soy food products, including soy sausage patties and soybean burgers)
• Soy flour
• Whole soybeans
• Tofu

The best way to find out about protein content is to look on the product's Nutrition Facts label to see the percentage of soy protein. Also look at the list of ingredients. If a product contains isolated soy protein (or soy protein isolate), the protein content should be fairly high.

Some products also list how many grams of soy protein are in one serving of the product.

Note: There's a difference between soy supplements (commonly sold in tablets or capsules) and soy protein products. Soy supplements are generally made of concentrated soy isoflavones. These substances may help relieve symptoms of menopause but there is not enough evidence to support using soy isoflavones for any of the other health benefits, such as lowering cholesterol.

For individuals who are not allergic to soy, no serious short-term or long-term side effects have been reported from eating soy foods.

Common mild side effects include stomach aches, constipation, and diarrhea.

Soybeans also contain moderate amounts of a natural substance called purine. Purines can make gout worse. Persons with gout should not eat alot of soy products.