Are GMOs a health problem?

The European Commission shifted the approval of genetically modified organisms (GMOs) for planting from DG envi to DG sanco, i.e. to the health directorate. Let us leave behind the principal question why in contrast to all other new crop varieties GMOs should be treated by a separate legislation; this was thoroughly analyzed in the White Book of Czech scientists1. Certain militant pressure groups are using health issue to affect public as the health is of most concern.

What are the reasons for expecting health risk of GMO to be different from any other new variety? New proteins potentially causing allergy and selection genes coding for an antibiotic resistance are claimed most frequently. The nptII gene is the case of potato Amflora.

By definition2 any new variety must be distinct, uniform, stable and new. Translated in the molecular biology terms it must express new genes or at least new forms of genes, what means new variety with no regard to the breeding method applied always generates new proteins. Consequently it brings in our food proteins we have not met before.

Most frequently used GMOs - glyphosate or glufosinate tolerant - carry genes transferred from soil bacteria. Our food, as revealed by hygiene norms, contains several millions of soil bacteria (colony forming units) per gram. Thus, soil bacteria, their genes and proteins are standard components of our food and GMOs containing them do not expose us to new proteins. It is true that these bacterial proteins when synthesised in eukaryotes might be glycosylated changing in this way different antigen activity. This was the essence of the of the alpha-amylase inhibitor case when the bean protein was produced in pea3. Nevertheless, even in such a case the GMO just lost the advantage of containing standard food component instead of a new protein.

The antibiotic resistance genes as a health risk are an evergreen of NGOs. Many studies have also been discussing this issue. Some factual, some rather scholastic speculations were assessing the hypothetical risk of such gene introduced by GMO into the human or animal gut being transferred to pathogens4. However, the presence of soil microorganisms in our food (and feed as well) should be also respected. Those who are arguing against, e.g. Amflora potato as risky by "spreading" the nptII gene in the environment should perform a simple experiment: plating the French, Italian or Greek dinner on an agar plate with kanamycine and counting the colonies. As the frequency of the npt gene in soil bacteria population is about 5% the result will show several hundreds of millions of it we eat every day.

Similar treatment of human or cattle faeces may bring information about the number of bacteria with antibiotic resistance genes generally present in the gut. These numbers shall be multiplied by the probability of bacteria-to-bacteria gene transfer. This show the offer of antibiotic resistance gene to the eventually present pathogen and the probability of its uptake. Then the estimate of antibiotic resistance genes introduced in the gut due to the use of GMOs (e.g. feed from the Amflora starch cake) should be multiplied by the experimentally estimated probability of plant-to-bacteria gene transfer. The probability of such transfer was discussed very thoroughly. In the above referred paper by Patrice Courvalain the author explains very low probability of plant-bacteria gene transfer if any. Comparing both results of resistance gene transfer will demonstrate the value of NGO's (and ex commissionaire Dumas's) arguments that the presence of the nptII gene in cells of Amflora represents a risk to human (and animal) health.

Are GMO free of any risk?

No, certain risk is attached to any new variety. But the crucial point consists in its position above or under the acceptable risk level. Varieties obtained by radiation mutagenesis carrying unknown number of unknown peptide mutants are placed below this level. Reading the 2000 annual report of he IAEA we learn that halo-tolerant radiation mutant of rice was introduced in general production (more than 200 000 hectares in the Mekong Delta) and is free on the market. On the other side few grains of GM rice in a shipment to EU triggers the "emergency situation". From results of Batista et al.5 we are informed that radiation mutant brings twice as much new proteins to our dish than GM variety. Why the latter caused emergency?

Nevertheless, the shift of the responsibility for approval of GMOs turned out to be very positive. The commissioner John Dalli from Malta started to respect the existing rules and on 2 March decided to make the industrial potato Amflora and three transgenic corn varieties free for planting. He preferred the freedom of Member state in taking the decision to cultivate the transgenes or not. He also stated that more transgenic crops will be released in such way. Hopefully new age is starting in Commission?

One takes as natural that missioners of para-religious anti-GMO groups are furious. They attack commissioner Dalli and try to preserve their brain washing of public with catastrophic scenarios they fabricate. As a result many European scientists addressed a supporting letter to the commissioner.

Author: Prof. Jaroslav Drobník