Genetically modified (GM) foods are widespread in Canada, with the potential for further expansion. Though the majority of studies show no negative health effects from consuming GM foods, there is controversy regarding the validity of these studies, and many significant concerns and unanswered questions regarding their effects on the environment.
Genetic Modification (GM) refers to the introduction of new traits to an organism in a way that does not occur naturally, by making changes to its genetic makeup through intervention at the molecular level.
The first GM crops were approved for sale in Canada in the mid 1990s, and they have since become pervasive: they are found in more than 70% of processed foods sold in North America. More than 90% of canola and sugar beets, 80% of corn and 60% of soy grown in Canada are genetically engineered.
While genetic modification can be undertaken for a variety of purposes, including nutrition improvement, virus resistance, and drought resistance, virtually all GM crops on the market today are engineered exclusively for herbicide tolerance or insect resistance.
Herbicide tolerant crops have been engineered to withstand application of herbicides: most common is Monsanto’s “Roundup Ready” corn, which tolerates glyphosate. Crops engineered for insect resistance produce their own pesticides. The most common are Bt crops, such as Bt Cotton and Bt Corn, which are engineered to synthesize Bacillus thuringiensis (Bt) endotoxin in their cells, making them toxic to some insects. Many GM crops are “stacked” with both herbicide tolerance and insect resistance.
There is a strong “right to know” movement advocating mandatory labelling of GM foods in the US and Canada. Polls show that 90% of Canadians support mandatory labeling, and 64 countries around the world have mandatory labelling. Going further, some countries have banned the cultivation of GMOs altogether. Some US states have passed mandatory labelling laws, but a bill is currently under consideration in the US Senate, which would mandate that any such labelling takes place only at the Federal level, and only if health and safety is shown to be at issue.
GMO foods have been widely consumed for 20 years. The majority of scientific studies undertaken suggest no negative health effects from consuming GMOs (see here and here). However, there are a number of criticisms aimed at these studies, including their short-term nature and the fact that industry funds a large proportion of them.
Some studies have shown negative health effects of GM foods, including toxicity, immune responses, hormonal effects, and allergenicity, but their results are also contentious within the scientific community. Many of the studies showing negative health effects focus on the effects of glyphosate, which the World Health Organization has listed as a probable human carcinogen, and Bacillus thuringiensis (Bt), which are present in GM crops but are also used in conventional, and, in the case of Bt, organic agriculture. It is debated whether the levels at which Bt is found in GM crops are higher or lower than in conventional or organic crops, and whether there are qualitative differences in Bt, with human health and environmental implications, depending on how it is used.
The environmental effects of GM crops are a second key issue. Herbicide resistant plants – so-called “super weeds” – are on the rise, resulting from the widespread use of herbicides, particularly glyphosate. Herbicide use has increased significantly since the advent of GM crops; one study estimates a 15-fold increase between 1996, when glyphosate-resistant crops were introduced, to 2014. Many draw a direct link between herbicide-resistant GM crops and the increase in herbicide use (see here and here, for example). In response to weed resistance to glyphosate, chemical companies are developing new herbicides and engineering crops to resist them, such as 2,4-D resistant corn and soybeans, grown with Dow’s Enlist Duo, which combines herbicides 2,4-D and Glyphosate.
The other major GM crop, modified with Bt to resist insects, has led to a reduction in the use of chemical insecticides in the US (the Canadian government does not track the impact of Bt crops on insecticide use). However, it is debated whether the GM plants have more or less pesticides present than those used in conventional or organic agriculture. Furthermore, since Bt has been used so widely in GM crops, insects are becoming resistant to it, thus farmers may have to switch to other, more toxic pesticides (see here, here and here).
In terms of contamination, GM crops have the ability to contaminate organic farms, which prohibit the use of genetic modification, thereby making organic farming difficult or impossible in regions close to GM agriculture. There is a largely unknown risk of transgene transference from GM crops to wild gene pools: some instances of transference have been reported, but the extent and future potential is unknown.
A Canadian expert panel put together by the Royal Society of Canada noted that the uncertain environmental impacts of GM crops could justify mandatory labeling. Independent research is lacking, as research is primarily funded by industry. The Canadian government doesn’t undertake an independent review process of industry studies on the health and environmental safety of their products before approving them.
Underlying discussions of the health and environmental effects of GM crops is a problem with treating GMOs categorically. Genetic modification is a process that can be used for different purposes and to a wide variety of effects. As noted, while herbicide resistant GM crops are associated with increased herbicide use, pesticide producing GM crops, such as Bt crops, have reduced the use of chemical insecticides. Genetic modification can potentially improve nutrition, such as “Golden Rice” with vitamin A added, or GM potatoes that release fewer carcinogenic acrylamides when cooked; it can make crops virus resistant, by inserting virus proteins into the DNA, as with the GM papaya; and it can help plants become drought resistant, potentially improving global food security. A key point of criticism of mandatory labelling is that it does not differentiate between the types of modification taking place, and their associated effects on human health or the environment.
Mandatory labelling has a significant amount of public and political support, advertised as a means to give customers the ability to know what they are eating. The effect of mandatory labelling on consumer demand is debated: some argue that it will be widely perceived as a warning, thereby decreasing consumer demand for GM products. In response to consumer demand it is predicted that producers will shift away from GM products and source non-GM ingredients. The costs of labelling to the consumer in Canada are debated, but a large study in the US estimated that mandatory labelling would cost US$2.30 per person annually, not incorporating potential behaviour changes.
Another significant issue is the role of chemical companies and large corporations in agriculture. A small number of large corporations exercise ownership over a large and growing amount of food. Farmers cannot save and replant GM seeds; they must purchase them from the manufacturers. There are fears seed diversity will be negatively impacted, impacting food security.
Whereas today GM foods are primarily present in processed foods and animal feed, there is potential for the commercialization of many other GM crops. Efforts are underway to commercialize the non-browning “Arctic Apple”, GM alfalfa, wheat, and some species of fish. What would the effects be of the expansion of the kinds of GM crops being grown, especially for our ability to grow organic produce?
GM crops have only been on the market since the 1990s, so the long-term effects on health and the environment cannot yet be conclusively known. Given the concerns regarding industry funding of scientific studies and the lack of long-term independent studies, many questions remain regarding the chronic and long-term effects of GM crops on human and animal health, and the environment.
Given the number and the extent of the unknowns associated with GM crops, precaution would suggest, at a minimum, mandatory labelling, an independent, peer-reviewed process to ensure the safety of GM crops before they are approved by government regulators, and long-term, well-funded independent studies on the effects of GM crop on human health and the environment. Mandatory labelling of foods containing genetically modified ingredients would enable people to choose if they want to consume GM foods and support GM technology through their purchases. It would also have the likely effect of decreasing demand for products containing GM crops, moving producers away from sourcing GM crops.
Labelling that specifies the nature of genetic modification (e.g. genetically modified for insect resistance; herbicide tolerance; vitamin A added) would differentiate between kinds of genetic engineering and make the information conveyed through labels more meaningful for consumers. Investigating the extent to which specific labelling is possible, what its challenges and costs would be, and whether there are best practices elsewhere, is suggested.
Industry is a significant source of funding for scientific studies on the health and environmental effects of GM crops, and the Canadian government does not independently review company studies on the safety of GM crops. Funding independent and long-term research on health, environmental, and other effects of GMOs would provide a trusted scientific source of information to inform policy going forward. The establishment of a national research program to monitor the long-term effects of GM organisms was recommended by the Royal Society of Canada expert panel to the Canadian government in 2001, but has not yet been realized.
It seems that many of the strongest motives for concern regarding GMOs come less from an issue with the technology of genetic modification itself, and more from the context in which it is taking place. Regulation and independent long-term research are lacking, and a small number of large chemical companies are driving forward a huge expansion of GM technology in the midst of many uncertainties and unanswered questions regarding its potential effects on our health and the health of our environment.