Soy and Women’s Health
Soy contains phytoestrogens called isoflavones. Phytoestrogens are naturally occurring plant compounds that mimic natural estrogens. Because of their isoflavone content, soy products can play an important role in women’s health, providing relief from the symptoms of premenstrual syndrome, easing symptoms of menopause, and preventing hormone-induced cancers.
Many women suffering from the monthly effects of premenstrual syndrome (PMS) have benefited from incorporating soy and soy supplements into their diet. PMS manifests itself to varying degrees through symptoms such as acne, bloating, backache, fatigue, extreme irritability, headache, sore or swollen breasts and depression. Several studies have shown that soy foods and soy supplements can have a beneficial impact on the effects of PMS. In short, soy isoflavones occupy estrogen receptor sites, causing a decrease in circulation estrogen. Lower levels of estrogen are known to result in fewer or less severe symptoms of PMS.
Soy protein is marketed as an alternative to hormone replacement therapy for women going through menopause. Soy isoflavones bind to the body’s estrogen receptors, but they are much weaker than the human hormone, so they probably do not increase the risk of hormone-induced cancers such as breast cancer. For women who cannot or do not want to receive estrogen replacement therapy, soy supplements may provide adequate relief from hot flashes and other menopausal symptoms.
The prospect of developing hormone-induced cancers (like breast cancer and ovarian cancer) is a major concern among middle-aged and older women. Fortunately, soy isoflavones such as genistein have shown impressive results in fighting cancer.
Genistein, which has only about one one-thousanth the hormone potency of estrogen, attaches to estrogen receptor sites in breast cells, preventing the much more potent and potentially carcinogenic estrogen from attaching to these same receptor sites.
Genistein also helps prevent cancer by slowing the activity of the hypothalamus and pituitary gland, which both contribute to estrogen production in the ovaries. When less estrogen flows through a woman’s body, her cycle lasts longer, translating to fewer cycles over her lifetime. Ultimately, this means that her exposure to estrogen will be less, thereby decreasing her risk of breast cancer and other conditions.
Researchers believe the genistein helps control tumor growth by enhancing apoptosis, or programmed cell death, which regulates all cell growth by not allowing them to reproduce too quickly.
Studies have also shown that genistein and other isoflavones can inhibit angiogenesis, the process by which new blood vessels are formed to feed tumors. Stopping this process causes tumors to become nutrient-starved and shrink.
There is also some indication that genistein may help the mammary gland cells to mature and diversity, thereby cutting the risk of cancer. The mammary glands of women who have never nursed are more immature and thereby more vulnerable to cancer formation.