by A K Perera
Soy has been, for centuries, a dietary staple in many Asian countries and has often been touted as the ultimate health food, for its low-fat, high-protein content. However, in recent years there have been growing concerns regarding genetically modified soybean crops, soy allergies and a possible link with breast cancer.
Here is the latest update on the following concerns we had:
Genetically Modified Soy
Soy Allergy On The Rise?
Potential Link to Breast Cancer
Genetically Modified Soy
Genetically modified (GM) food or food derived from genetically modified organisms (GMO) is a contentious topic at present. Genetic modification of crops such as soybean and maize involves the incorporation of new proteins (transgenic proteins) that allow them to be more resistant to herbicides and pests. However, there is much concern over the long-term effects associated with the consumption of these GM foods. According to an article in the April 2009 issue of Toxicological Sciences, food allergy is a potential risk associated with use of transgenic proteins in crops. In Canada, approximately 65 percent of soybean crops are genetically modified.
Over 35 countries have mandated the compulsory labeling of any product that has been genetically modified. In Europe for example, all food containing 0.9 percent or more GM product must carry a GM label. The Food and Drug Administration (FDA) in the U.S. however, has found GM foods to be nutritionally equivalent to non-GM food and therefore does not require labeling. Similarly, Health Canada considers GM food to be as safe as conventional food and only mandates the labeling of food that has been pasteurised, irradiated or contains allergens such as peanuts, wheat or soy. The differences in attitude to GM labeling between Europe and North America has been attributed to both increased pressure from environmental groups and the number of food scares that have occurred throughout Europe in recent years, ranging from mad cow to foot and mouth disease. (http://www.choicesmagazine.org/2003-2/2003-2-01.htm).
Soy Allergy On The Rise?
Estimations of common food allergies include: cow's milk, 2.5 percent; egg, 1.3 percent; peanut, 0.8 percent; wheat, 0.4 percent; and soy, 0.4 percent. A report from the Centers for Disease Control and Prevention (CDC) has indicated an 18 percent rise in food allergy among children in the past decade. According to Health Canada, food allergies affect as many as 6 percent of young children and 3 percent to 4 percent of adults. Despite the overall rise in food allergies, soy allergy remains a minor contender, especially when compared the cow's milk allergy, which affects more than six times the population.
Soy allergy often manifests at a young age, usually after exposure to soy-based infant formula, which ironically, tends to be introduced after allergy to milk-formula. Although many children outgrow soy allergy, for some, the condition persists through to adulthood. Common signs and symptoms of soy allergy include itching, hives, wheezing, diarrhea and vomiting. Rarely, a severe immune reaction, known as anaphylaxis, may occur which can be fatal.
While soy is an obvious ingredient in foods such as soymilk, tofu and soya sauce, it is present in less obvious foods such as cereals, candies and even ice cream, making avoidance quite challenging.
Link to Breast Cancer?
Recently, there have been concerns over soy consumption and the risk of breast cancer. This is due to the fact that isoflavones, naturally occurring compounds present in soybean, have weak estrogen-like effects in the body. However, in addition to it's mild estrogen-stimulating properties, isoflavones have been found to inhibit specific enzymes expressed by cancer cells. Studies carried out so far, seem to indicate the safety of isoflavone consumption, such as the recent analysis of current clinical data in the June 2008 issue of the Nutrition Journal, which showed isoflavone consumption to have no significant effect on breast tissue in healthy or breast cancer patients. Another study published in the December 2009 issue of the Journal of the American Medical Association found soy to confer a protective effect in breast cancer patients. Other studies remain inconclusive. It is worth noting however; that many of the studies done so far have only been carried out on animal models or small numbers of human subjects, leaving the debate about soy and its relationship to breast cancer, to continue among researchers. Large-scale, long-term clinical trials are needed.
1. Toxicological Sciences; Safety Assessment of Biotechnology Products for Potential Risk of Food Allergy: Implications of New Research; Mary Jane K. Selgrade, Christal C. Bowman, Gregory S. Ladics, Laura Privalle, Susan A. Laessig; July 2009
2. Crop Life Canada: Biotech Facts
3. CBC News: Genetically Modified Foods a primer
4. Choices: International Approached to Labeling Genetically Modified Foods
5. Emedicine: Food Allergies
6. Mayo Clinic: Soy Allergies
7. Nutrition Journal; Soy isoflavones, estrogen therapy, and breast cancer risk: analysis and commentary; Mark J Messina, Charles E Wood; June 2008
8. Journal of the American Medical Association; Soy Food Intake and Breast Cancer Survival; Xiao O. Shu et al; December 2009
A British medical doctor turned freelance writer, Anu Perera began writing health articles in 2010. Perera has presented several posters at national meetings and has been involved in health education for more than four years. She now resides in Southern Ontario with her husband and young son.
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