OAFT News: Let’s not go there again!

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Gord Surgeoner
May 1999


Science Reporting and Public Perception

GMO potatoes:

In the fall of 1998 and spring, 1999, the media in the United Kingdom erupted with claims that ‘genetically modified potatoes’ adversely affected rats in terms of both growth and immune function.

Dr. Arpad Pusztai of the Rowett Institute in the U.K conducted the experiments that caused this widespread public fear of genetically modified food. The experiments involved feeding rats potatoes either genetically modified to express lectin, a gene found naturally in the snowdrop plant, or potatoes with lectin added but not genetically modified. Lectin is produced naturally by some plants to protect themselves from insects.

We stress that these potatoes were not in the food system and they would never be sold as food if there were adverse effects to mammals.

In response to the public concerns and because Dr. Pusztai’s work had not been peer reviewed, the Royal Society of England convened an independent review of the study. The results released May 1999 were as follows:

  • On the basis of the information available, it appears that the reported work from the Rowett Research Institute was flawed in many aspects of design, execution and analysis and that no conclusions should be drawn from it.
  • No convincing evidence of adverse effects from GM potatoes was found upon review. Where the data seemed to show slight differences between rats fed predominantly on GM and on non-GM potatoes, the differences were not interpretable because of the technical limitations of the experiments and the incorrect use of statistical tests.
  • The work concerned one particular species of animal, fed with one particular product modified by the insertion of one particular gene by one particular method. However skillfully the experiments were done, it would be unjustifiable to draw from them general conclusions about whether genetically modified foods are harmful to human beings or not. Each GM food must be assessed individually.
  • The whole episode underlines how important it is for research scientists to expose new research results to others able to offer informed criticism before releasing those results into the public arena.

The bottom line is that widespread fear was created in consumers by flawed, non-peer-reviewed science, that would not have been accepted for publication. The media entered the feeding-frenzy without waiting for independent evaluation.


  • The Royal Society is an independent academy promoting the natural and applied sciences. Founded in 1660, the Society has dual roles; as the UK academy of science, acting nationally or internationally, and as the provider of a broad range of services for the scientific community, including fellowships and grants.

The Monarch Butterfly:

In May 1999, John Losey and others from Cornell University published an article in Nature entitled ‘Transgenic pollen harms Monarch larvae’. I emphasize that the article was peer reviewed and as such meets one of the first tests of reputable results. The concern is how the media is interpreting the results to suggest that transgenic pollen from corn is causing the elimination of Monarchs which some have described as the ‘Bambi of the Insect World’.

First the experiment was a laboratory study designed to determine if toxicity existed. Leaves lightly misted with water were treated with pollen that visually matched milkweed leaves from cornfields. The caterpillars tested were 3-days old, which is very young, and one would expect maximum toxicity in young larvae.

This experiment indicates that there is ‘potential risk’ to Monarchs and field studies are required. E.g. how likely is it for Monarchs to feed on milkweed within a cornfield? How often is the pollen likely to stick to the leaves? How far would sufficient pollen move to cause toxicity outside a cornfield?

Importantly, how much of a risk is this compared to:

  1. herbicide treatments used to control this noxious weed
  2. destruction of overwintering grounds in Mexico
  3. mortality of adult Monarchs by automobiles

The laboratory study requires follow-up with field research to ascertain the risk in nature. Until then, media should refrain from reporting the demise of the Monarch from genetically modified corn.

Written by Dr. Gord Surgeoner
President, Ontario Agri-Food Technologies
& Faculty Member, University of Guelph
May 1999

Monarch Butterfly Researchers Urge Caution in Over-Interpreting Results
10 June 1999
Let’s not go there again!
Gord Surgeoner
May 1999
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