Soybeans, which are eaten as a healthy and tasty snack, are rich in a substance called isoflavones. These seeds are produced by soaking raw soybeans, then drying them, and then roasting the dried seeds. Soy may not belong to the nut family, but in some ways it has similar properties. Hundreds of medical studies have shown that isoflavones in soy are useful in preventing heart disease and a variety of cancers. These seeds also contain significant amounts of plant protein.