Substantial equivalence unraveling

February 2014

picture of green soybean pods
Green soybeans. CC photo by UD Carvel REC on Flickr
The basis for safety assessment of GM foods has always been 'substantial equivalence'. 

The phrase has no scientific basis, but seems to mean “close nutritional and elemental similarity between a genetically modified (GM) crops and a non-GM traditional counterpart” (Bohn).
Without any definition of 'close', 'similarity', 'nutritional', 'elemental', 'traditional', or 'counterpart', the concept can be applied to achieve just about any outcome regulators or the biotech industry choose to concoct.

Back in the 1990s, the most-planted GM crop so far commercialised, Roundup Ready soya, was pronounced 'substantially equivalent' whether it had been sprayed with Roundup herbicide (the form always on the market) or grown unsprayed (a form only ever found in laboratories).

Despite the hype about how GM crops reduce pesticide use, actual pesticide levels have never been factored into the 'substantial equivalence' assessments.  Nor have pesticide levels in GM crops ever been systematically monitored in the US, UK or Canada. 

Aware of a glaring knowledge gap regarding nutrient and elemental qualities, and the pesticide levels, in the GMOs in our food chain, a team of Norwegian scientists carried out a real-life survey of GM soya. 

To limit environmental influences, they selected crops within a  200 kilometre radius in a major soya-growing area in Iowa.  They then compared three types of soya based on its agri-management:

  1. Roundup Ready soya (10 crops) sprayed with glyphosate (the active herbicidal ingredient of Roundup) and various routine pesticide treatments.
  2. Conventional soya (10 crops) subject to various routine pesticide treatments.
  3. Organic soya (11 crops) grown without chemicals

COMMENT  Fertiliser treatments were, presumably, tailored to the individual plot by the farmer.

The varieties of soya tested represented a real-life cross section within each category, although there were some identical strains grown under more than one regime.

Nutrient levels will vary with a crop's genetic background and with environmental influences.  The limited control over both these factors in this 'real-life' study would be expected to lead to wider variations which would blur the distinctions between crops under the three agri-management systems studied. 

However, using 35 different nutritional and elemental variables to characterise each soya sample, the Norwegian scientists were able to discriminate GM, convention and organic beans, without exception.

 This appears to demonstrate 'substantial non-equivalence' in ready-to-market soya. 

Interestingly, the organic soya showed the healthiest nutritional profile with more sugars, significantly more total protein and zinc, less fibre, and less saturated fat and omega-6-fatty-acids than the GM or conventional beans. 

Non-glyphosate pesticide residues were surprisingly little in evidence: contamination at levels of hundredths of a milligram per kilogram was found in one GM and one conventional sample; contamination at a level of thousandths of a milligram per kilogram was found in one organic sample; trace levels (less than one microgram per kilogram) of four pesticides were found in all samples, indicating a general background level of chemical pollution in cropping environments. 

Total glyphosate (i.e. glyphosate plus its major metabolite, 'AMPA') was absent from conventional and organic beans, but clearly present at levels of up to 15 milligrams per kilogram in all GM samples (Note that this is four orders of magnitude higher than any other chemical residue tested).  Since Roundup Ready soya is designed to accumulated glyphosate, its presence was to be expected, but the levels found were unexpectedly high. 

Glyphosate contamination in Roundup Ready beans (representing 75% of global soya production) was below the 'maximum residue level' (MRL) of 20 milligrams per kilogram set in most countries.  However, the MRL seems to have been fixed in response to the needs of GM soya producers, rather than with regard to a safety limit.  Recent reports of endocrine-disrupting [1,2], embryo-damaging [3], and cancer-promoting [2,4] effects of glyphosate a very low levels of exposure are putting the current MRL in doubt. 

It seems also that regulators have paid little heed to the effects of time plus the large-scale use of Roundup Ready crops.  Both these factors have shaped today's real-life soya supply. 

Back in 1999, Monsanto claimed that glyphosate-contamination in Roundup Ready soya was less than that arising in conventional crops which have been treated with the herbicide as a harvesting aid.  The latter was quoted to be in the region of 16-17 milligrams per kilogram.  In the same year, Monsanto claimed that a contamination of 5.6 milligrams per kilogram glyphosate found in GM soya represented “extreme levels, and far higher than those typically found”. 

As the current study (14 years on) shows, glyphosate accumulation in some GM crops is now approaching the levels only previously seen in pre-harvest treated crops when there has been no time for dissipation of the herbicide.  Also, seven out of ten GM samples now exceed the previous, untypical, “extreme level”. 

As Roundup-resistant weeds become endemic in American fields, it seems clear that Roundup Ready crops are being sprayed with more glyphosate, more often and closer to harvest time as the years go by.  What's entering the food chain now in soya doesn't seem to be substantially equivalent to conventional soya, nor to the soya which was originally approved by regulators.


Glyphosate and AMPA are known to be toxic to plants, reducing photosynthesis and interfering with metal-ion-dependent physiological processes.  As the contamination increases, is it likely that the GM plants' altered physiology will produce crops which remain 'substantially equivalent' to non-glyphosate-treated crops (if they ever were)? 

An EU review of glyphosate safety and its MRL is about to be released.  The report is expected to recommend business as usual and the raising of the MRL from  0.3 mg/kg body-weight/day to 0.5 mg/kg.  New data emerging from up-to-date, more sophisticated, scientific techniques has been ignored as has the consistent finding that Roundup formula, which is what we are actually exposed to, is more toxic than glyphosate. 

Next-generation GM crops will be tolerant to glyphosate plus at least one other herbicide.  Safety studies of such future chemical cocktails are essential, as is monitoring of our exposure to all of them, and a close watch on how the cocktail is affecting plant nutrient 'equivalence'. 

Ask DEFRA and the EU regulators to reconsider glyphosate safety on the basis all recent studies on Roundup as a matter of urgency.



[2]  GLYPHOSATE AND CANCER - September 2013

[3]  ROUNDUP CAUSES BIRTH-DEFECTS - (Document link) GMFS ARCHIVE - October 2010


T Bohn, et al, 2014, Compositional differences in soybeans on the market: Glyphosate accumulates in Roundup Ready GM soybeans, Food Chemistry 153

Germany claims no problem with glyphosate, GM Watch 23.01.14

Christopher Schrader, Controversial glyphosate poison can be sprayed, 22.01.14

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