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what are some safty problems with GMOs

Submitted by: gilkerso


Expert response from Robert Wager M.Sc.

Faculty Member, Biology Department, Vancouver Island University in Nanaimo BC Canada

Friday, 30/01/2015 15:05

When discussing safety of GM crops and derived food it is easier to separate the food safety aspects from the environmental aspects.  This answer will deal with food safety issues.


Every GM crop is extensively tested for food safety considerations before it is allowed to be commercialized.  The testing protocols are based on internationally agreed criteria (OECD, WHO).  A good document that outlines the testing protocols is the Guidance for risk assessment of food and feed from genetically modified plants: EFSA Panel on Genetically Modified Organisms (GMO).


The following areas of food safety are examined:


  • Principles of Risk Assessment (4 subcategories)
  • Molecular Characterization (2 subcategories), Comparative Assessment (5 subcategories)
  • Toxicological Assessment (5 subcategories)
  • Allergenicity Assessment (3 subcategories)
  • Nutritional Assessment (2 subcategories)
  • Exposure Assessment and Risk Characterization. 


When GM critics complain that the biotechnology companies do the safety testing they forget to say that which tests, how many tests, and with which controls are all dictated to the company.  Only when all the dictated tests are done to exact standards and with acceptable outcomes does the company get approval to commercialize the GM crop. 


Crops from a variety of other breeding methods (most with far more DNA disruptions than GM crop breeding) are barely tested at all for any of the food safety considerations listed above.


Sometimes animal feeding studies are called for by regulators.  An excellent review article that outlines animal feeding studies is also from the European Food Safety Authority. This report has over 300 references to such studies.  They state:


“Many feeding trials have been reported testing GM maize, potatoes, rice, soybeans and tomatoes on rats or mice for prolonged periods, and parameters such as body weight, feed consumption, blood chemistry, organ weights, histopathology, etc., have been measured. The food and feed under investigation were derived from GM plants with improved agronomic characteristics like herbicide tolerance and/or insect resistance. The majority of these experiments did not indicate clinical effects or histopathological abnormalities in organs or tissues of exposed animals. These studies can be used to assist the safety evaluation of GM plant derived food and feed and to reach conclusions on whether they can be considered as safe as their conventional counterpart.”


Critics often say 90-day feeding trials are insufficient.  The EFSA report also states:


“Laboratory animal feeding studies of 90-days duration appear to be sufficient to pick up adverse effects of compounds that would also give adverse effects after chronic exposure, and therefore in general, chronic toxicity testing of GM food and feed does not seem to generate additional valuable information to the safety assessment.”


Even though long term studies add little to the safety testing, there have been quite a few carried out.  The conclusion of a review of these long term studies states:


“We examined 12 long-term studies (of more than 90 days, up to two years in duration) and 12 multigenerational studies (from two to five generations). We referenced the 90-day studies on GM feed for which long-term or multigenerational study data were available. Many parameters have been examined using biochemical analyses, histological examination of specific organs, hematology and the detection of transgenic DNA. The statistical findings and methods have been considered from each study. Results from all the 24 studies do not suggest any health hazards and, in general, there were no statistically significant differences within parameters observed. However, some small differences were observed, though these fell within the normal variation range of the considered parameter and thus had no biological or toxicological significance. If required, a 90-day feeding study performed in rodents, according to the OECD Test Guideline, is generally considered sufficient in order to evaluate the health effects of GM feed. The studies reviewed present evidence to show that GM plants are nutritionally equivalent to their non-GM counterparts and can be safely used in food and feed.”


Herbicide tolerant crops have been the target of a massive misinformation campaign.  The most common HT crop is tolerant to applications of glyphosate.  Recently a series of junk science papers have implicated glyphosate in many diseases.  If one looks at the “research” in these papers it becomes clear improper procedures, inadequate controls, inappropriate statistics and mere correlations are used to allege the harm.  But if one looks at proper science it becomes clear glyphosate does not represent a threat to human or animal health.


When looking at insect resistant crops like Bt crops the health benefits are well documented.


Taken together all the GM food safety testing can be summed up by this statement from the European Commission document, A Decade of EU-Funded GMO Research 2001-2010:


“The main conclusion to be drawn from the efforts of more than 130 research projects, covering a period of more than 25 years of research, and involving more than 500 independent research groups, is that biotechnology, and in particular GMOs, are not per se more risky than conventional plant breeding technologies.”


Health Canada was just as clear when they stated:


“The overwhelming body of scientific evidence continues to support the safety of NK603, genetically modified food and feed products in general, and glyphosate containing herbicides.”


The American Association for the Advancement of Science was equally clear with their statement:


“The World Health Organization, the American Medical Association, the U.S. National Academy of Sciences, the British Royal Society, and every other respected organization that has examined the evidence has come to the same conclusion: consuming foods containing ingredients derived from GM crops is no riskier than consuming the same foods containing ingredients from crop plants modified by conventional plant improvement techniques.” 


Once one becomes familiar with the actual level of testing that every GE crop must go through, it begs the question to ask GE critics.  “What tests not already done would you like to see added to the evaluation of GE crops and why?”


The internet is full of misleading or blatantly false information about GMOs.  There is science and there is “science” and unfortunately the average person is not trained in the disciplines to be able to distinguish between the two. 


In 1987 the National Academy of Sciences (US) released this statement:


“There is no evidence that unique hazards exist either in the use of rDNA techniques or in the movement of genes between unrelated organisms.”


Almost thirty years later and thousands of studies the global science community has the same conclusion about the safety of GE crops and derived food.