The need for rigorous biological risk assessment

By Dr. Arpad Pusztai

According to present rules, GM crops need to be subjected to a number of in vitro examinations by the biotech companies. However, these are neither scientifically rigorous enough nor are adequate to decide whether GM food is safe or unsafe. Moreover, in vitro tests cannot be substitutes for in vivo biological testing that is in the first place carried out with laboratory animals. Although extrapolation from animal studies to the human situation is of questionable value, the demonstration of harmful effects of GM food in animals should alert us to the possibility of similar deleterious effects in humans. Thus, animal testing should be a part of the screening process and not the whole process.

GM food is unlikely to be highly poisonous and instantaneously deadly. Its likely harmful effects may only become apparent in the long term. "Toxicity" is therefore an unhelpful concept as the FDA (Food and Drug Administration, USA) found out that it was impossible to carry out an LD50 type toxicity test with FLAVR SAVR tomatoes because there was a physical limit to the amount of tomatoes one could gavage rats with. In contrast, nutritional studies in which GM crop-based diets are fed to young growing animals should reveal their possible harmful effects on metabolism, organ development, immune and endocrine systems and gut flora which together determine the safety of the GM crop for that particular animal species. All experiments should be done with both male and female animals and followed by studies of reproductive performance for several generations.

Statistically significant differences between GM- and parent-line diets would indicate that the GM crop cannot be used in human/animal diets. If both the GM- and parent-line diet spiked with the gene product show differences, the use of this gene is unacceptable. If the negative effects of the GM food are not observed with the parent supplemented with the isolated gene product, it is likely that the harm is caused by the construct or an unwanted or unforeseen effect of the gene insertion in the genome.

Animal testing is but a first step in the evaluation of the possible safety hazards of GM foodstuffs. If they reveal no harm, the results will next have to be validated with human volunteers in clinical double-blind, placebo-controlled drug-type tests but keeping in mind that the harm can be most acute in the young, elderly and sick, particularly those suffering from HIV, hepatitis or other viral diseases. Such tests must run over a long period of time.

I believe that testing of major individual GM crops must be started up urgently using this kind of protocol or other similar protocols. However, for the findings to carry any conviction with a sceptical public, the testing must be done openly, transparently and inclusively and confirmed independently.