Ask a Dietitian

As seen on BCTV November 27/01

Part 1: GM Foods – What are they?

You may have been hearing about GM foods, or GMO, or even novel foods, but what are they exactly? GM foods (genetically modified foods) or GMO (genetically modified organisms) have been genetically engineered (GE). Genetic engineering involves removing genes from one organism, plant, animal or microbe- and transferring them to another. Most genes are simply codes or blue prints, that tell a cell to make a protein. So far, most genetically engineered food ingredients are made from plants. They are found in products like corn flakes made using GE corn or salad dressing made with oil from GE soybeans. GE fish are in the works and meat and poultry are years off.

Why transfer genes? To give it a desirable trait, for example, corn has been genetically modified with a gene from soil bacterium to allow it to produce its own pesticide, harmless to humans, but protects it from the European corn borer.

There have been 48 genetically modified foods approved by Health Canada, most derived from genetically modified crop plants such as:

• corn (resistant to corn borers and herbicides)
• canola (resistant to herbicides
• potatoes (resistant to Colorado potato beetles)
• tomatoes (ripen more slowly)
• squash (virus)
• soybeans (round-up herbicide)
• sugarbeets (not being grown because farmers fear consumers won’t buy them)
• flax
• cotton (resistant to various worms and herbicides)

Canada is the world’s third largest grower of GE crops, behind the US and Argentina. 20-30% of soybeans, 40% of corn and 80% of canola grown in Ontario are GE. Most of the corn and soy crops are fed to animals, so the meat and poultry Canadians eat is likely to come from animals raised on GE feed.

Should we be nervous? No, by the end of processing corn into corn oil or glucose-fructose, the genes have been virtually all removed. But even if the foods we eat do contain the new genes or protein, that isn’t necessarily a problem. We eat foods with new genes and proteins all the time, the tomatoes, potatoes and wheat we buy in the grocery store have been genetically altered by breeding them with relatives (cross-breeding). We are constantly eating the genes and proteins of harmless bacteria that inadvertently end up on our food.

Part 2: GM Foods – Are they Safe?

With the increasing prevalence of GM foods in the market place, many people are wondering whether they are safe for consumption. Health Canada is responsible for assessing the safety of products intended for human consumption, while Canadian Food Inspection Agency (CFIA) is concerned with their impact on the environment and safety of products intended for animal consumption. In terms of safety for humans, Health Canada has 2 major concerns: 1) Do the new genes or proteins produce toxins? 2) Do they produce a protein that triggers an allergic reaction in a person who eats the food? Health Canada also evaluates:

• the process used to develop the modified or novel food
• its characteristics compared to the unmodified food
• its nutritional quality compared to the unmodified food

Have new allergens ended up in a GE crop? Yes. A gene from a Brazil nut was inserted in to soybeans and produced an allergen. This was detected through a routine test and the soy was never marketed. Another example is the US Starlink corn, which contains a gene taken from a bacterium to produce a protein called Cry9C, a major killer if the corn borer. But because this protein passes through the digestive tract intact it was recognized as a potential allergen. The corn was only approved for animal feed but tiny amounts of it was mixed with other corn and ended up in taco shells and caused a few cases of allergic reactions in humans. From then on the USEPA (US Environmental Protection Agency) decided that they will only approve crops for animals that are safe for people to eat too.

Are they less nutritious than conventional foods? No. They typically have the same amount of vitamins, minerals, protein and other major nutrients as conventional foods. Companies don’t normally test for phytochemicals like lutein or lycopene because they’re not yet considered nutrients. However, Health Canada should consider changes in key phytochemicals when it decides to approve foods or not.

Will consumers ever benefit? They already do from reduced pesticides. As techniques become more sophisticated, scientists may be able to introduce more complex changes that benefit consumers more directly. For example; companies are working on developing fruit that can be picked ripe without becoming mushy, coffee that is naturally caffeine-free and soybeans that don’t trigger allergic reactions and contain more healthful omega-3 fatty acids. It will be years before we see those foods. Scientists are close to making a GE rice called “golden rice”, that contains vitamin A, for developing countries with vitamin A deficiency. They are also working on crops that can withstand droughts or grow in salty soils.

Are there any environmental concerns? Yes, new genes in GE crops that are now resistant to herbicides could spread to their wild relatives and other plants and create “super weeds” which won’t respond to current “safe” herbicides. Pesticide resistance is still an issue, whether an insect becomes resistant to the bacterial pesticide made by GE corn or to the pesticide conventionally used. Insects will become resistant either way.

How can we identify GM foods? In response to increasing public demand, the federal government is presently looking into mandatory labeling for all products containing GMOs. However, labeling of food products containing GMOs is presently voluntary. It is currently only mandatory to label any safety concerns regarding allergies or nutritional changes to the foods in order to alert consumers or susceptible groups, while the CFIA monitors labels for misrepresentation and fraud.

Watch for the Eating for Energy segment every Tuesday on BCTV’s Noon News Hour!