Cancer prevention :  There are two primary isoflavones in soybeans, daidzein and genistein, of which genistein is the most predominant.  Substantial evidence shows that genestein can actually hinder the process of hormone-related cancer cell development such as breast cancer, which is the leading cause of death of women in the United States between the ages of 35 and 44.  Genestein acts as an antiestrogen which blocks the growth of estrogen-dependent cancer cells and inhibits the enzymes necessary for this type of cancer growth (Ziegler 1994, Henderson 1999, United Soybean Board 1998).

Research also shows that isoflavones can block testosterone, thereby inhibiting the growth of prostate tumors. Other studies show that the isoflavones in soybeans can cause existing cancer cells to "differentiate" or transform from a cancer cell to a normal cell (Caton 1999). 

Decreased Symptoms of Menopause: The primary symptoms of menopause are caused by a decrease in the production of estrogen in women.  Because isoflavones' chemical structure is comparable to that of estrogen, hormones that are essential for the female reproductive system, isoflavones have been shown to help reduce the symptoms of menopause such as hot flashes (Barnes & Kim 1998, Indiana Soybean Board 1998).

Osteoporosis: Loss of bone calcium is a leading cause of osteoporosis. Many studies demonstrate that soybeans can help prevent osteoporosis (The Wellness Report 1999).  While soybeans are a rich source of calcium, recent studies show that soy calcium is easily absorbed, and that it's absorption rate comparable to that of milk (ALS Network 1999).  Furthermore, both Isoflavones daidzein and genestein have been shown to reduce the loss of calcium from bones, as well as improve bone quality and maintain bone health (OBGYN.net 1998, United Soybean Board 1999).