Phytoestrogens also operate as antioxidants, which inhibit the growth of cancer. And soy protein causes less calcium excretion from your body than animal protein. Soy confers so many benefits that I'd like to see everyone make it regular part of their diet. I recommend one serving a day to reduce your risk of breast cancer, and up to two a day to relieve menopausal symptoms. Go up to between two and four if you want to lower cholesterol, and eat more than four if you aim to decrease the risk of osteoporosis.
Soy milk is basically smashed, strained soybeans pureed in water.
For variety, eat a half cup of tofu, a half cup of tempeh or a half cup of green soybeans as the equivalent of one serving. If you don't like the flavor of soy, you can try the milk flavored with almond or vanilla. Soy milk is high in calcium, but not as high as cow's milk. So look for a calcium-fortified brand. Also, many soy crops are heavily treated with pesticides, so buy organic soy products if you can.