Alert on glyphosate

Foods made with genetically modified organisms (GMO) are certainly the first ones to eliminate from one’s diet in order to keep away from toxic residues. Indeed, these crops have been purposely modified genetically to withstand higher doses of herbicides and pesticides used by farmers in order to increase yield. However, the growing use of herbicides is not restricted to GMOs and concerns a large list of crops. The Food Issues Committee has been paying attention to this increasing trend in agriculture for GMO crops and beyond.

One common herbicide of concern is a chemical called glyphosate, also known by its trade name Roundup. A 2015 memorandum on glyphosate usage from the US Environment Protection Agency, presented data on 70 crops grown in the US using glyphosate, including cucumber, tomatoes, spinach, strawberries and almonds, to name only a few. The report points out that the quantities of glyphosate applied have been growing for 47 of the 70 crops, compared with similar data from 2007. 

In addition to application to GMO crops, another reason for the growing use of glyphosate is that farmers have changed their practices and now rely even more on chemical sprays than would be necessary just for weed control purposes. Crop desiccation, the process of spraying crops with pesticide just prior to harvest, is a good example. This practice is intended to correct for uneven crop growth, achieve more even ripening, allow earlier harvest (and therefore earlier replanting), and diminish strain on harvesting machinery.

Glyphosate was first authorized by the Canadian government for pre-harvest treatment on wheat, barley, soybeans, peas, lentils, canola, and flax in 1992, shortly after the establishment by Health and Welfare Canada of Maximum Residue Limits (MRLs) for glyphosate in the Food and Drug Regulations. Even though pre-harvest spray increases the possibility of glyphosate residues remaining in/on harvested crops and surrounding environment, this new practice was not considered harmful to consumers as long as the residues remained below the MRLs. Even in 2019, Health Canada continues to maintain this position although a 2016 report from the WHO International Agency for Research on Cancer has classified glyphosate as “probably carcinogenic” from a hazard perspective, but unlikely to cause cancer in people via dietary exposure when below MRLs. 

In short, the development of GMO crops is only one of the reasons behind the increasing use of glyphosate, and it is becoming harder and harder for us as consumers to distinguish which food items are more likely to contain toxic residues. One guarantee remains valid, though: organic specifications prohibit the use of synthetic fertilizers and pesticides, with a few rare exceptions, and glyphosate is not among those exceptions. If your own personal MRL for glyphosate is zero, choosing organic food is probably the safest option available today. Unless, of course, you know your farmer and trust their practices.

submitted by Nathalie Rémond for the Food Issues Committee

Thank you to Karma member Kenneth MacDonald for forwarding a news article on this issue to the Food Issues Committee.

Ask Reece

Dear Reece,

Could you provide me with evidence that organic food is healthier than conventional? I am trying to convince a friend, who has apparently seen studies that show there is no difference between organic and pesticide-laden foods. I find this hard to believe.

Cares About Real Organic Treats


There are a couple of literature reviews, the highest form of evidence-based science, summarizing studies on organic food vs. conventional in aspects of human health (Mie, A., 2017; Gomiero, T, 2017). Neither are perfect, or perfectly conclusive, partly since nutrition studies are notoriously hard to conduct in a meaningful or long-term way (Gallegos, J, 2017). Nutritionally, the studies cited above show mixed results, with not more than a marginal benefit to eating organic, if any. As far as poisonous residues goes, there are more residues on conventional produce, but there isn’t conclusive evidence that these directly affect human health at current levels. They do affect workers’ health, though (Gomiero, T, 2017). There is some correlation between general health outcomes and eating organic foods, but there is no way to tell if that is from the organic foods or some other factors that are likely part of the lifestyle of organic food eaters (Gomiero, T, 2017). See how it’s tricky? I would add that none of these studies use local, small-farm organic foods, and there could be a significant difference nutritionally between those, and “organic” produce imported from large multinational companies (I like that Karma labels produce from specific local farms/farmers).

The question I ask myself is: does a scientifically measurable increase health from eating organic matter? There are a lot of good reasons (a reduction in greenhouse gases (Squalli, J. 2018) [farm workers’ health (mentioned above), soil health (Lori, M., 2017)] beyond human health to eat local organic produce – maybe your friend would be interested in one of those reasons. Or maybe not. Did you know it’s really hard to shift people’s opinions by presenting them with facts? Unfortunate, but true. It is so well-established it has a name in psychology – belief perseverance – and may be linked to our ability to develop hypotheses about the world from a young age (Savion, L, 2009)

Back to our subject: there is also the related benefit of supporting small, local producers, and being part of a community or network of people who care about similar things. If you and your friend still disagree on the benefits of organic food, I hope the two of you can still enjoy each other’s company and also perhaps a lively discussion about this topic you both have an interest in.

Kind regards,

Ask Reece is the Chronicle’s advice column by Karma working member Reece Steinberg, a health sciences & culinary arts librarian and food enthusiast. Reece provides advice with input from a variety of sources including anything from traditional etiquette columns to peer-reviewed scientific articles. He answers Karma member questions about dietary lifestyles, food science and fermentation, eating etiquette, and anything else, really. Please email your questions to