There is no denying that soy has many health benefits. These health benefits are mainly coming form the quality of the soy proteins and form the isoflavones genistein and daidzein.  Isoflavones and lignans from soy and flax seeds interact with intestinal bacteria to form hormone-like compounds that have a weak estrogenic effect as well an antioxidant effect in the body. Phytoestrogens influence many key functions in the male and female body:

• Sex hormone metabolism
• Biological activity of cells
• Enzyme function
• Herbal Beauty
• Protein production
• Growth factor action
• Preventing malignant cell proliferation
• Ensuring proper cell differentiation
• Prevention of angiogenesis (increased blood supply generated by cancer cells to give them sufficient oxygen and nutrients for their abnormal growth and proliferation)
• Genistein is important in the prevention and treatment of cancer. It inhibits the enzyme tyrosine kinase produced by oncogenes, as well as angiogenesis. It’s also a potent antioxidant that blocks the signal triggering the growth of cancer cells. Research also shows that genistein is anti-estrogenic in breast cancer. It inhibits the activity of oncogenes and has the ability to change cancer cells back to normal ones.
• Daidzein acts as an antioxidant and anti-cancer agent. It can turn cancer cells back to normal ones by restoring gap-junction communication between cells.
• Isoflavones compete with the oestrogen implicated in breast and prostate cancer. By blocking oestrogen receptor sites, cancer-causing oestrogen is prevented from entering the cell to trigger abnormal cell growth. Isoflavones also increase the level of SHBG (sex hormone binding globulin, the protein that carries the sex hormones through the body) which blocks excess oestrogen.
• Isoflavones also have a chemo-preventive effect because they inhibit the proliferation of cancer cells.
• Soy has been used successfully in treating cancer of the breast, prostate, stomach (except for miso — too much salt), lung and skin.
• This all sounds very promising, but much more research remains to be done.