Soy is a versatile legume with a long history of use for its culinary and medicinal effects. Estrogen-like compounds in soy have been promoted as a natural form of estrogen replacement for menopausal women seeking to reduce hot flashes and other symptoms of menopause. However, some experts assert that adverse effects of soy may outweigh its benefits.
Allergic Reactions
Soy is a highly allergenic food that can cause a range of health problems, including infertility, weight gain, depression and fibroids, according to Dianne Gregg, author of the book "The Hidden Dangers of Soy." In a study published in the July 2011 issue of "Clinical and Experimental Allergy," workers at a factory that manufactures soy-based cereals tested positive for soy allergy at a rate five times higher than a control group with no soy exposure. Sensitivity to multiple soy allergens was detected, and an association between soy allergy and occurrence of asthma was noted.
Digestibility
Processed soy foods, such as defatted soy flakes, are indigestible, says acupuncturist Aimmee Ellen Raup, L.Ac., M.S., author of the book "Chill Out and Get Healthy: Live Clean to Be Strong and Stay Sexy." The phytoestrogens they provide accumulate in your body and lead to excessive estrogen, increasing your potential for developing breast and ovarian cancer, endometriosis, fibroids and infertility. By contrast, a study conducted at the Cancer Center, University of Hawaii, and published in the July 2011 issue of "Cancer Epidemiology Biomarkers and Prevention" found that high-soy diets did not result in elevated blood levels of estrogen and do not increase breast cancer risk.
Excessive Levels
The current recommendation by the Food and Drug Administration of 25 g of soy protein per day is four times more than is consumed in the average Asian diet. Additionally, the forms of soy consumed in Asian diets is unprocessed and fermented, as opposed to the highly processed soy flakes that are included in many commercially prepared Western foods. These soy derivatives find their way into as much as 60 percent of packaged foods.
Toxicity
Soy contains toxic compounds that inhibit digestive enzymes, leading to digestive disorders and impaired amino acid absorption, says Dr. Asa Andrew, author of the book "Empowering Your Health: Do You Want to Get Well?" These toxins are disabled by the process of fermentation used in the making of traditional soy products, but are present in soy milk, soy flakes and other modern soy products. Soy also contains compounds that affect thyroid function, known as goitrogens, compounds that have the ability to inhibit thyroid function.
References
- "Clinical and Experimental Allergy"; Occupational Sensitization to Soy Allergens in Workers at a Processing Facility; B. Green et al.; July 2011
- "The Hidden Dangers of Soy"; Dianne Gregg; 2008
- "Chill Out and Get Healthy: Live Clean to Be Strong and Stay Sexy"; Aimee Ellen Raupp, L. Ac., M.S.; 2009
- "Empowering Your Health: Do You Want to Get Well?"; Asa Andrew; 2007
