Debate on GMOs health risks after statistical findings in regulatory tests

Abstract

We summarize the major points of international debate on health risk studies for the main commercialized edible GMOs. These GMOs are soy, maize and oilseed rape designed to contain new pesticide residues since they have been modified to be herbicide-tolerant (mostly to Roundup) or to produce mutated Bt toxins. The debated alimentary chronic risks may come from unpredictable insertional mutagenesis effects, metabolic effects, or from the new pesticide residues. The most detailed regulatory tests on the GMOs are three-month long feeding trials of laboratory rats, which are biochemically assessed. The tests are not compulsory, and are not independently conducted. The test data and the corresponding results are kept in secret by the companies. Our previous analyses of regulatory raw data at these levels, taking the representative examples of three GM maize NK 603, MON 810, and MON 863 led us to conclude that hepatorenal toxicities were possible, and that longer testing was necessary. Our study was criticized by the company developing the GMOs in question and the regulatory bodies, mainly on the divergent biological interpretations of statistically significant biochemical and physiological effects. We present the scientific reasons for the crucially different biological interpretations and also highlight the shortcomings in the experimental protocols designed by the company. The debate implies an enormous responsibility towards public health and is essential due to nonexistent traceability or epidemiological studies in the GMO-producing countries.

Keywords: Animal tests; GMOs; Health risks; Pesticides; Regulatory toxicology.

Fig 1

Proposed mode of actions of agricultural GMOs and/or associated pesticides on health. Almost all GMOs disseminated in the environment are plants, namely soy, maize, cotton, and oilseed rape (1995-2010). Their genetic and phenotypic modifications are only herbicide tolerance and / or insecticide production (modified Bt toxins) in more than 99% cases. Thus they can be described as pesticide plants. Consequently, two major health risks are described: (1) due to mid or long term side effects, brought by new pesticide residues in food or feed, and directly due to the new genetic characteristic. These residues can be from herbicide(s) absorbed by tolerance (Roundup residues in more than 90% herbicide-tolerant GMOs) in most cases, or from new modified insecticide Bt toxins, mutated or truncated in all insecticide-GMOs. (2) Insertional mutagenesis linked to the genetic modification, or post-genomic metabolic interferences or derivations. These are direct or indirect less specific effects independent from the toxicology assessment of the transgene product. These unexpected possible consequences cannot be approached by gross substantial equivalence studies without metabolomic analyses. They can be invisible on the plant phenotype, but still able to induce long term toxicity after consumption, specific to each genetic transformation. The possible combined effects between all these impacts cannot be excluded, inducing chronic pathologies after regular consumption. Only long term testing (more than 3 months in mammals) could answer these possibilities. Thus, regulatory agencies must adapt their methods for health risk assessments of agricultural GMOs, taking into account associated pesticides and their formulations. They should also approach combined effects at different periods of life and on several generations, to be complete, overall when a new food/feed concerns billions of people without traditional knowledge of its consumption.