Genetically modified foods (GM foods or GMOs) breed controversy. While the pro-GMO camp argues genetic modification will enhance nutritional, social, medical, and production values that can solve many of the world's problems, those opposed fear that scientists and companies are ignoring medical and environmental issues that could destroy the world. No wonder so many of us are confused about whom to believe!

NOTE: For more on GM foods see, "Lunchtime Low-Down: The Science of GM Foods."

The pro-GMO group is often led by businesses out to make money, and a lot of it. In fact, development and production of GM foods is a multi-billion dollar industry. So, can we trust people who want to sell us these things?

On the other hand, some of the fears that anti-GM groups advertised are groundless. For example, the concern that eating GM foods containing altered DNA is dangerous is unrealistic because the body digests nucleic acids—approximately 100 million kilometers of DNA every day!—without knowing if it came from a non-modified food source or from a GMO.

Did You Know?
A person eats DNA from multiple different sources every day, including vegetables, fruits, meat, etc...

However, one valid concern is the potential for GMOs to cause allergic reactions. Food allergy is a well-studied and very dangerous medical concern that affects about 2% of adults, 8% of children, and hospitalizes many Canadians every year. Most of us have a friend or relative who carries an EpiPen® in case he or she accidentally eats the wrong food. Not knowing what is in their food can mean death for these people!

Did You Know?
Common food allergies include nuts, eggs, peanuts, dairy, and shellfish.

Food allergies arise because we produce proteins called antibodies, known as IgE. IgE antibodies protect us from bacteria and toxins in the environment by catching foreign proteins that our bodies do not produce. When this happens, IgE bind to the protein and then to white blood cells, which leads to coughing, sneezing, swelling, runny noses and watery eyes, vomiting, and throat constriction. This is the body's method to eliminate, and prevent ingesting, harmful proteins.

Did You Know?
An allergic reaction is the body's method for eliminating foreign, potentially harmful compounds.

Sometimes, however, IgE antibodies recognize proteins in foods, particularly in nuts, shellfish, eggs, and milk. The concern that GM foods could produce immune reactions is because:

Adding a gene (a.k.a. a transgene) from foods that cause allergic reactions (e.g. peanuts) into common foods (e.g. rice), could be disastrous if people allergic to peanuts ate the modified rice. Introducing a transgene that is too close to another gene might create a new fusion protein that is the two proteins joined together. IgE may recognize this fusion protein as foreign, even if it does not recognize either original protein, and initiate an allergic reaction. Putting a foreign protein to a complex biological system—as all living things are!—may change the host's metabolism and increase normal proteins to an allergenic level.

Currently, the first of these reasons is the only one demonstrated to occur. One company inserted a gene for a Brazil nut protein containing essential amino acids, methionine and cysteine, into the soybean. With this soybean, farmers could feed animals a complete diet with no animal by-products, and vegetarians who eat soy-based products such as tofu would conveniently get enough methionine and cysteine.

Unfortunately, some people who were allergic to Brazil nuts were allergic to the transgenic soybeans because their IgE recognized the Brazil nut protein in the modified soybeans. As a result, the project was stopped and all soybeans destroyed before animals or humans could eat them.

Some GMOs, however, do not present an allergy risk. For example, some GM crops contain a gene that makes them resistant to herbicides, meaning farmers can spray a specific herbicide that kills all plants except the ones with the gene. Farmers also have the option of planting GMOs with a transgene known as Bt from the bacteria Bacillus thurigiensis. Bt kills caterpillars who eat the bacteria. Therefore, plants expressing the Bt gene kill caterpillars that try to eat them and reduce the need to use pesticides on these crops.

Did You Know?
GMOs that carry the Bt transgene produce Bt toxin that kills caterpillars.

These GMOs are safe for humans to eat because the transgenes are nearly identical to genes found in unmodified plants and therefore produce proteins unrecognizable by IgE. Wheat, corn, soy, and cotton are a few plants that are available with these genes.

Another option for allergy-free GM crops is to make GMOs that do not produce new proteins. For example, the Flavr-SavrTM tomato was a GM tomato modified to produce RNA that inhibits a gene responsible for breaking down the tomato's cell walls and going soft. These tomatoes could be grown on the vine longer and shipped without being squashed. Because these tomatoes do not produce any extra proteins, there is no risk of allergic reaction.

To ensure our safety when eating GMOs, the World Health Organization and the Food and Agriculture Organization developed rigorous regulations companies must follow while making a new GMO. Companies consider:

Is the transgene from a plant that causes allergic reactions? Does the transgene encode a protein that has 6 or 8 continuous amino acids matching any known allergens? Does IgE recognize the new product?

If the answer to any of these questions is yes, then production stops. To date, Health Canada, the US Food & Drug Administration, the European Union, and the scientific community recognize no legitimate reports of allergic reactions to available GM foods, which suggests that the process to make allergy-free GM foods works.

For more information, see:

Health Canada, Food and Nutrition

World Health Organization: GM Foods

National Institutes of Health MedLine Plus: Food Allergy

USFDA Center for Food Safety and Applied Nutrition


JA Nordlee, SL Taylor, JA Townsend, LA Thomas, RK Bush. Identification of a Brazil-nut allergen in transgenic soybeans. N Engl J Med. 1996 Mar 14; 334(11):688-92.

W Burks, BK Ballmer-Weber. Food allergy. Mol Nutr Food Res. 2006 Jun 30; 50(7):595-603

HV Davies. GM organisms and the EU regulatory environment: allergenicity as a risk component. Proc Nutr Soc. 2005 Nov; 64(4):481-6.

Derrick Randall did his Bachelor of Science in Biochemistry & Molecular Biology, his Master of Science in Medical Genetics, and currently studies Medicine at the University of British Columbia in Vancouver, BC. Derrick grew up on Vancouver Island and loves nature.


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