There are three main groups of components in soy. They are useful in controlling viruses and are currently being used to treat patients with the AIDS virus. Saponins bind to cholesterol and make it unavailable for reabsorption in our bodies. Even more cholesterol is removed from the blood afterwards. Saponins also stimulate the growth of intestinal bacteria that help build a stronger immune system, once again, warding off viruses.
Saponins also reduce the risk of some cancers.
Since cancer cells look a lot like cholesterol, and Saponins bind to cholesterol, they also bind to some cancer cells and help rid the body of them. Most foods contain very small amounts of isoflavones, but soybeans contain relatively larger amounts. These substances have no nutritional benefit, but they may help reduce the risk of many chronic diseases, such as cardiovascular disease, osteoporosis and cancer. They may also be helpful in reducing the symptoms of menopause. So isoflavones are really the source of many of the health benefits enjoyed by those who include soy in their diet.