- The study conclusion is not supported by the data the authors presented.
- Environment and geography are known to have a major impact on composition and undoubtedly affected the results of the study.
- The compositional differences the authors reported could be due to differences in genetics, location or environment.
- Glyphosate residues on GM beans were as expected and are within the established tolerance.
The paper “Compositional differences in soybeans on the market: Glyphosate accumulates in Roundup Ready GM Soybeans” by Bøhn and colleagues seeks to compare the nutritional quality of three different groups of soybeans, one grown using organic methods, a second grown using conventional agricultural practices and a third that uses genetically modified (GM) varieties that are tolerant to the herbicide glyphosate (the active ingredient in Roundup agricultural herbicides). The study’s conclusion that “in the present study organic soybean samples had a more profitable nutritional profile than industrial conventional and GM soybeans” is not supported by the data the authors presented. Let me explain why.
There are many different varieties of soybean, which can naturally have different levels of seed components (protein, vitamins, minerals, etc.). When the authors collected the soybean varieties for this study, they separated them into the three groups — organic, conventional and GM. Unfortunately, each group contained different soybean varieties, with no overlap (with one exception) of varieties between the three groups, so each group was already inherently different from the others. Even the authors acknowledge that different varieties can have widely different seed composition. Therefore, concluding that any differences between the groups in this study were due to the way the soybeans were grown (organically or not), or the presence/absence of a glyphosate-tolerance gene in the GM varieties, is simply not possible. The three groups are expected to produce different results because they started out with different genetics.
Another main limitation of this study has to do with geography. The old adage that “location is everything” is true for real estate and for agriculture. The authors note that all the samples came from within a 200 km (120-mile) radius, which they described as a “well-defined geographical region.” If I were to load my family into our minivan and drive the 120-mile radius from our house in the St. Louis region, we would cover a lot of different types of terrain. This is important because location can be a huge contributor to crop composition differences. Even over very short distances, soil types, available water, mineral content, weather patterns and other factors can vary dramatically, impacting the development and composition of the plant. Since the plants in this study were not grown together but rather taken from separate fields across a region spanning a 200 km radius, any real differences between the three groups can’t be separated from the variation caused by location, and no reliable conclusion about their nutritional quality can be made. To put this in context, we are looking at satellite imagery to help farmers make more-informed decisions by increments of meters, not miles.
Finally, when we take into account the effects of genetics and location, we see that the compositional differences the authors observed in this design are not unexpected. Protein levels in soybeans generally average ~40 percent dry weight (dwt) but have been shown to range naturally from 34.1 to 56.8 percent dwt (Wilson, 2004). This natural variability can be due to variety, location or environment, and it means that people are already consuming soybeans with larger variability than the differences in soybeans reported here.
I respect the fact that consumers (including me and my family) want to know how modern agricultural technology and practices are affecting, and even improving, the quality of our food. At the very least, we should expect that the “experts” providing the information would make sure that the messages they are conveying are grounded in solid science. Studies like this one reported by Bøhn serve only to confuse and in some cases mislead consumers. At a time when we should be thoughtfully considering all avenues for effective and healthy agriculture, good decisions will need to be based on good science.
The second finding reported in this paper was that RR soybean contained higher residue concentrations of glyphosate and its breakdown product AMPA (aminomethylphosphonic acid). It is interesting to note that there were residues found on organic soy as well, but that didn’t seem to cause concerns. It is important to remember that both glyphosate and AMPA residues are thoroughly evaluated prior to registration of any new use to determine whether measured levels fall within currently accepted tolerances. Tolerances are established only if the dietary exposure from that use is within previously established limits. The results from Bøhn et al. clearly confirm that glyphosate and AMPA residues are within the tolerance. As a result, this is totally expected and normal.
Glyphosate has an excellent human health and environmental profile and a long history of safe use in more than 130 countries. In fact, all independent health assessments conducted by public authorities in Europe and internationally over the past 40 years have consistently concluded that glyphosate does not pose any unacceptable risk to human health.
Wilson, R.F. 2004. “Seed composition.” Soybeans: Improvement, Production and Uses. 3rd Edition. H.R. Boerma and J.E. Specht (eds.). ASA, CSSA, SSA, Madison, WI.