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Posted: May 2014

Glyphosate-resistant GM soybeans differ compositionally from non-GM soybeans and contain high residues of the herbicide glyphosate

Most of the soybeans grown around the world today (over 75%) are genetically modified so that they do not die when sprayed with the herbicide glyphosate. This has led to a dramatic increase in the amount glyphosate sprayed on the crop. Bøhn et al. (2014) collected three different types of soybeans that have been grown commercially in Iowa:
  1. genetically modified (GM) soybeans that were resistant to glyphosate; they had been harvested from fields that had been sprayed with the herbicide and other pesticides;
  2. conventional, non-GM soybeans that had not been sprayed with glyphosate, but had been sprayed with other herbicides and pesticides;
  3. organically grown, non-GM soybeans that were not treated with any chemicals.
The researchers subjected these three different groups of commercially grown soybeans to compositional analyses. They found:
  • “Using 35 different nutritional and elemental variables to characterized each soy sample, we were able to discriminate GM, conventional and organic soybeans without exception, demonstrating the ‘substantial non-equivalence’ in compositional characteristics for ‘ready-to-market’ soybeans.” The result calls into question the determination of U.S. Food and Drug Administration that most GM crops are “substantially equivalent” to non-GM crops, in which case the GM crops are designated “Generally Recognized as Safe” and therefore do not require pre-market approval.
  • The GM soybeans contained significant amounts of residues of glyphosate (mean 3.3 mg/kg) and its breakdown product AMPA (5.7 mg/kg); the conventional and organic soybeans did not contain these chemicals. The maximum allowed residue level (MRL) for glyphosate in food and feed has been raised in past years—for example in 2004 in Brazil from 0.2 to 10 mg/kg; in 1999 in Europe from 0.1 to 20 mg/kg; the U.S. has adopted the European standard. The authors remark that, “in all of these cases, MRL values appear to have been adjusted, not based on new evidence indicating glyphosate toxicity was less than previously understood, but pragmatically in response to actual observed increases in the content of residues in glyphosate-tolerant GM soybeans.”


Bøhn, T., M. Cuhra, T. Traavik et al. (2014). “Compositional Differences in Soybeans on the Market: Glyphosate Accumulates in Roundup Ready GM Soybeans,” Food Chemistry vol. 153, pp. 207-15. Open access article:

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