Soy Protein Suppresses Breast Cancer Hormones Antioxidant compounds found in soy foods have been shown to reduce levels of hormones associated with breast cancer risk in women. Now, the results of a small study suggest that other factors associated with soy may also play a role in lowering cancer risk. The investigators found that nine healthy, premenopausal women who consumed a diet containing soymilk in which most of the antioxidant compounds, isoflavones, had been removed, produced less estrogen and progesterone than they produced before they added soy to their diets. Other reproductive hormones were not affected by the diet, which was also low in animal protein and high in fiber, the researchers report. According to the study in the July issue of the Journal of Clinical Endocrinology and Metabolism, estrogen levels fell as soy protein and fiber intake increased. However, Dr. Lee-Jane W. Lu, the study's lead author, stressed that it is not yet clear which dietary compounds caused the change in hormone levels. "The important finding from my study is that it is not too hard to lower a woman's...female hormone," she told Reuters Health. "By replacing-not supplementing-a portion of one's energy intake (with) soy, one can lower one's female hormones.'" Estrogen can stimulate the growth of some types of breast cancer cells and is thought to play a role in the development of some cases of breast cancer. Women with a higher lifetime exposure to estrogen-for instance, those who got their first period at an early age, those who do not have children and women who do not breastfeed- may face a higher risk of breast cancer. The hormone progesterone also contributes to breast cancer risk by helping tumors to grow. "Our results may have implications for breast cancer prevention by soy dietary intervention," according to Lu and her colleagues at the University of Texas Medical Branch in Galveston. In the study, researchers measured levels of estrogen, progesterone, sex hormone-binding globulin, luteinizing hormone (LH) and follicle stimulating hormone (FSH) in women before they began the diet. LH and FSH stimulate ovarian function. The women followed the diet, which included 36 ounces of soymilk containing less than 5 milligrams of isoflavones daily, for one month. The study diet contained more carbohydrate and less protein than the women's usual diets, the report indicates. Journal of Clinical Endocrinology and Metabolism 2001;86:3045 ====================================================================== Breast Cancer News is brought to you by the The MID HUDSON OPTIONS PROJECT, INC a grassroots Breast Cancer Health Advocacy, Support and Activist Group Bio Pharm Bull, 4/01 Am J Clinical Nutrition, 12/01 Breast Cancer Res 1/02 Cancer, 3/02 Obstet Gynecol, 3/02 Estrogen Metabolism & Soy Isoflavones Cancer Epidemiology, Biomarkers & Prevention, 9/02 J Carcinogenesis, 5/04 Brit J Cancer, 6/05 Int J Cancer, October 2008 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.