Soy, an annual legume of the pea family, is extensively grown in tropical and warm temperate regions across the world for its protein-rich seeds. It is originally from southeastern Asia, but today soy has become generalized throughout Europe and the United States, the U.S. being the world's major soy producer. Soy can add a good amount of protein to a woman's diet; however, scientists aren't sure whether soy is beneficial or harmful for estrogen-dependant breast cancer. So, before you decide to take soy food supplements, be sure to consult with your doctor.
Soy Estrogens and Other Ingredients
Soy is abundant in isoflavones, chemicals with antioxidant properties, particularly genestin and daidzen, which structurally and functionally resemble to the body's natural estrogen, a steroid hormone that is predominant in the female reproductive system. Isoflavones contained in soy are also classified as soy estrogens. Soy is also a good source of lycine -- a valuable amino acid; linoleic and linoleic acids -- two essential fatty acids; soluble fiber; vitamins -- such as folic acid, ascorbic acid, folic acid and vitamin B6; and minerals -- such as magnesium, potassium and iron.
Estrogen-Positive Breast Cancer
When you have breast cancer, the cells that make up the tissues in the breast become abnormal and divide without order or control. It is generally agreed that high estrogen concentrations in the body put women at a higher risk for breast cancer, according to a 2000 study conducted by Wen-Yi Huan and his colleagues of the The Johns Hopkins University School of Hygiene and Public Health, which was published in the journal "American Journal of Epidemiology." Estrogen increases breast tumor growth via proliferation of milk-producing glands or lobules of the breast. Most breast cancers originate from these milk ducts.
Negative Effects of Soy Estrogens on Breast Cancer
According to the Sprecher Institute at the Cornell University, soy isoflavones mimic the action of estrogen and cause an increase in cell proliferation in breast tissue. However, it is not fully understood how soy isoflavones, also known as soy estrogens, exert these actions. Because of the structure, soy isoflavones can easily attach to the beta-receptors of estrogen, found in the bones and cardiovascular system, and therefore may have estrogen-like effects.
Positive Effects of Soy Estrogens on Breast Cancer
Proponents of soy argue that soy isoflavones are weak estrogens and they actually act like anti-estrogens by inhibiting the hormonal effects of the body's own natural estrogen when estrogen levels are high. Researchers consider that soy isoflavones can alter the mechanisms or pathways that facilitate the development of breast cancer, according to a 2010 study conducted by Anne Weaver of the University of Buffalo.
References
- University of Maryland Medical Center: Soy
- Cornell University: Sprecher Institute: Phytoestrogens and Breast Cancer
- Soy Isoflavones Decrease Risk of Invasive Breast Cancer, Large Breast Tumors, Study Shows; Anne Weaver; 2010
- Columbia University Health Sciences: Estrogen's Role in Cancer; Susan Conova; 2010
- "American Journal of Epidemiology": Hormone-related Factors and Risk of Breast Cancer in Relation to Estrogen Receptor and Progesterone Receptor Status; Wen-Yi Huan and et al; 2000
