PHYTOESTROGENS,
THE STORY OF ISOFLAVONES AND SOY

Plants are super foods; orange plants are loaded with Vitamin A, the cruciferous family is rich in anti-oxidents, leafy greens contain high amounts of calcium, iron and vitamin C. In addition, plants have hormones; called phytoestrogens, from the Greek "phyto" for plant. And among the family of plant estrogens, isoflavones are potent cancer fighting agents. In pre-menopausal women, estrogens are an integral part of the regulatory mechanism of the menstrual cycle; help the development of breast tissue; and contribute towards the secondary sexual differences between women and men. Estrogen production declines in post-menopausal women by up to 70 per cent, contributing to the uncomfortable symptoms of menopause, to weaker bones, as well as an increase in risk for breast cancer (the number two cancer killer of women). Prostate cancer is the number two cancer killer in men. The male hormone testosterone has a tendency to hasten the growth of prostate tumors. Phytoestrogens appear to slow down or inhibit cancerous cell growth in both men and women. Isoflavones are found in the greatest concentration in soybeans and soy products . The main isoflavones are daidzein, genistein and genistin. They provide the essential benefits of estrogen to women without the threat of cancer. While an optimal daily amount of isoflavones is currently unknown, numerous experiments (see below) with soy products indicate that substituting a single serving of daily protein with a soy based food may provide this beneficial protection. How? One suggested mechanism is that isoflavones compete with estrogen by mimicking estrogen's role in the body. For example, look-alike phytoestrogen "genistein" occupies the place in breast tissue cells of the real estrogen, thus preventing the more potent natural estrogen from converting normal cells into cancer cells. Another idea is based on the differences in menstrual cycle lengths between Japanese women living in Japan and in the U.S. Soy based foods are a staple in the Japanese diet. Japanese women have as much as 15 to 20 times as high a concentration of isoflavones in their blood as American women. Their menstrual cycle is on the average three to four days longer than American women, thus exposing them to fewer hormonal surges. Evidence indicates that soy products may help relieve such menopausal symptoms as hot flashes and night sweats. In an 18 week study, researchers from the Bowman Gray School of Medicine in North Carolina examined the effects of soy on 43 women ages 45-55 experiencing these symptoms. For six weeks the women added 20 grams (under 1 oz, approximately 2 teaspooms) of powdered soy protein to their daily breakfast. For another six weeks, they added the same amount of soy protein to their diets, but split into two 10-gram doses. For a third six-week period, they added a look-alike powdered carbohydrate placebo. Significantly less severe hot flashes and night sweats were reported by those taking the soy. In addition, total cholesterol levels dropped an average of 10%. Elsewhere on the Internet, you can find further research in the use of phytoestrogenes to reduce menopausal hot flashes. Abstract Likewise for men, death due to prostate cancer in the Orient occurs much later in life and to far fewer men than in the U.S. In the U.S., prostate cancer strikes one in 11 men, causing 38,000 deaths per year; but in Asia, where soy and other phytoestrogen containing foods are eaten more frequently, men fall victim to prostate cancer later in life and often die from other causes before their tumors become lethal. How much? While there are no recommended daily allowances for Isoflavones, one daily serving of a soy food may assisst in the prevention of certain cancers, reduce menopausal symptoms, and provide a healthfull alternative to meat. Still not convinced? Take a look at a complete nutritional profile for various forms of soy, and browse through our introduction to the large variety of soy based foods . Return to our Home Page