Those receiving the soy supplement took 60 grams each day over a 12-week period. Research shows that Japanese women, who regularly consume soy products rather than animal protein, report markedly fewer menopausal symptoms than American women. Japanese women also have only one-fourth as much breast cancer as American women. Substituting soy protein for animal protein can help slash breast cancer risk at any age because of its genistein content. Genistein is a chemical that blocks an enzyme that turns on cancer genes and inhibits the growth of new blood vessels needed to feed growing cancers.
Studies also show that eating a soy-rich diet can help build bone mass.
This is because eating animal protein washes away much more calcium out of the body through the urine than consuming soy protein. One study showed that women eating meat lost 50 milligrams more calcium per day than when they ate the same amount of protein in soy milk. This is very significant. Difference of 50 mg calcium loss a day can translate to substantial loss of bone mass when we spread it over a 20 year period. Common menopause symptoms such as mood swings and hot flashes, insomnia, depression, diminished sexual vitality and decreased bone mass may be effectively managed by drinking a cup of soy milk and eating four ounces of firm or soft low-fat tofu each day.