Pesticides, GMOs, and the Intestines
by Jacqueline Gutierrez, MS, MSEd, RD, CDN
reviewed by Marlisa Brown MS, RD, CDE, CDN
In recent years there has been a lot of discussions about whether GMO’s have an effect on our health, so to due to this buzz we wanted to share some information on what is known so far. Genetically modified organisms (GMOs) are living things that contain genetic information that has been changed scientfically (AKA manipulated) by man using methods that would not happen naturally on their own. There are many GMO crops that are now being grown in the United States, and they have become part of the commercial food supply. Overall the percentages of genetically modified foods and foods containing pesticides have greatly expanded over the years. Currently at least 70-80% of commercially available foods in the U.S. contain at least one genetically modified ingredient. There are scientists who have studied the relationship between ingestion of pesticides, herbicides, as well as genetically modified foods and the incidence of wheat related allergies and intolerances, in order to ascertain if there was a relationship between the two. However, there is not enough research to support or deny any such relationship at this time. Currently it is important to note that genetically modified wheat is not yet available in the United States.
The six major genetically modified crops grown and sold in the United States are soy, corn, cotton (used for oil), canola (oil), sugar beets (sugar), and alfalfa (animal food). Many of these crops were engineered to be herbicide tolerant, and contain high levels of herbicides. Some of these crops, such as genetically engineered corn, also produce the Bt toxin insecticide as they grow. Bt toxin makes its way into corn tortillas, corn chips, and other corn containing items. In addition, many genetically engineered crops such as corn, soy, canola, sugar beets, and alfalfa are engineered to tolerate the pesticide glyphosate and are routinely sprayed with this pesticide which remains in the foods grown from these crops. For those following a gluten-free diet such as those with celiac disease it is important to note that corn is commonly used in many gluten-free baked and cereal products.
When someone suffers from celiac disease the consumption of gluten leads to increased intestinal permeability. If you were able to look at the intestines you would see that they are bonded together tightly in a way that looks like a barrier keeping things from crossing into the body in an unnatural way. If there is an increase in intestinal permeability it would result in this barrier not being as protective as it normally would be. Our intestines are responsible for about 70% of our immune system, making it an important protective system within our bodies. There are many things that are being studied to see if they are responsible for causing a breach in this system. For example, the Bt-toxin is used as an insecticide that works by creating holes in the digestive tracts of insects, thus killing them. Bt corn was introduced into the U.S. diet in 1996. The EPA classified the Bt toxin as only harmful to insects, not to humans. However, some recent data supports that the Bt toxin may lead to small holes in mammalian intestinal walls as well. The discussion here is that incompletely digested proteins that are absorbed into the bloodstream through large pores are more likely to lead to an allergic reaction than proteins that are more completely digested. Studies have shown that both Bt-toxin and glyphosate led to damage to intestinal microvilli in animals. In humans the villi line the intestines in a hair like barrier that helps increase nutritional absorbtion as well as serving as a protective barrier. Some speculation explores the possibility that the reaction found in mammalians the small holes may also be present in humans, in turn it it could possibly lead to to increased sensitivities or allergies. However it is important to note that this relationship is not yet established in humans. In addition, other researchers found that mice that were fed genetically modified soy had reduced pancreatic enzyme production. All of this stimulates more questions, fueling more reaserch; however, more research is needed before we can make any definitive statements about the effects of these substances on the human body.
Bottom line, the vote is out until more research is done. If while you are waiting for the findings you would like to limit genetically modified foods and pesticides in your diet, look for corn and soy containing foods that are organic or non-GMO certified.
References:The Facts About GMOs, Grocery Manufacturers Association Position on GMOs. The Grocery Manufacturers Association website. http://factsaboutgmos.org/disclosure-statement. Updated n.d. Accessed February 3, 2014.
Hemmelgarn M. Thinking Critically About GMOs. The HEN Post. Hunger and Environmental Nutrition, a Dietetic Practice Group of AND. Summer 2013.
Samsel, A. and Seneff, S., Glyphosate, Pathways to Modern Diseases II: Celiac Spruce and Gluten Intolerance. Interdiscip Toxicol. 2013; vol 6 (4); 159-184
Smith J. Are Genetically Modified Foods A Gut-Wrenching Combination? Institute For Responsible Technology website. http://responsibletechnology.org/glutenintroduction. Updated 2013. Accessed January 26, 2014.
Smith J. Can Genetically-Engineered Foods Explain the Exploding Gluten Sensitivity? Institute For Responsible Technology website. http://www.responsibletechnology.org/gluten. Updated 2013. Accessed May 29, 2014.