Ask a Dietitian


By Althea Zanecosky, MS, RD, LDN

Q: Food allergies seem to be on the rise. Some people say that eating foods with GMOs (genetically modified organisms) can cause food allergies. Since cows eat corn and soy, foods that have GMOs, will the GMOs show up in that cow’s milk? And could that then cause a milk allergy?

A: Rest assured, you cannot develop a milk allergy by consuming milk from cows fed GMO grains. Saying a cow eating GMO feed produces GMO milk is like saying a cow that eats chocolate is going to produce chocolate milk. It’s not going to happen. Genetically modified (GM) refers to a technology that can simply introduce a new protein to a plant.

While a food allergy is an immune reaction to a specific food protein, a milk allergy is an immune reaction to one of the many proteins in animal milk. Published research has shown there is nothing in milk that is obtained from cows fed GM crops that would make a person more allergic to milk.

When animals eat, their digestive tract breaks down the proteins and nucleic acids (genes) in food into smaller biological building blocks, called nucleotides and amino acids. This digestion process occurs identically, regardless of whether the animal’s feed comes from GMO crops or non-GMO crops. This makes the movement of whole GM proteins and whole GM nucleic acids, from GM feed into milk, physiologically impossible.

The U.S. Food and Drug Administration has determined that foods from GM plants are safe to eat (1). There is no evidence of GMOs being hazardous to human or animal health in the many years of testing that have been involved in this food technology. Also, testing for food allergy is not difficult. Food allergy experts and scientists, including from University of Nebraska-Lincoln, say food allergy tests are a standardized technology applied regularly in the development of GM products.

It is important to realize that genetically modified crops have been in the American food supply for over 15 years. In that time, there has never been a single food allergy associated with the particular proteins that are introduced by GMOs. This comes as no surprise, since genetic engineering regulations in the United States require food allergy tests to be conducted before any food product is ever allowed on the market.

For more information, visit either of these resources:

(1) Food from Genetically Engineered Plants at
Consumer Info About Food from Genetically Engineered Plants at