Scarcity of safety tests

How can the public make informed decisions about genetically modified (GM) foods when there is so little information about its safety? The lack of data is due to a number of reasons, including:

• It’s more difficult to evaluate the safety of crop-derived foods than individual chemical, drug, or food additives. Crop foods are more complex and their composition varies according to differences in growth and agronomic conditions.

• Publications on GM food toxicity are scarce. An article in Science magazine said it all: “Health Risks of Genetically Modified Foods: Many Opinions but Few Data”.¹ In fact, no peer-reviewed publications of clinical studies on the human health effects of GM food exist. Even animal studies are few and far between.

• The preferred approach of the industry has been to use compositional comparisons between GM and non-GM crops. When they are not significantly different the two are regarded as “substantially equivalent”, and therefore the GM food crop is regarded as safe as its conventional counterpart. This ensures that GM crops can be patented without animal testing. However, substantial equivalence is an unscientific concept that has never been properly defined and there are no legally binding rules on how to establish it.²

When food-crops are genetically modified, (“genetically modified” food is a misnomer!) one or more genes are incorporated into the crop’s genome using a vector containing several other genes, including as a minimum, viral promoters, transcription terminators, antibiotic resistance marker genes and reporter genes. Data on the safety of these are scarce even though they can affect the safety of the GM crop. For example:

• DNA does not always fully break down in the alimentary tract.^3,4 Gut bacteria can take up genes and GM plasmids5 and this opens up the possibility of the spread of antibiotic resistance.
• Insertion of genes into the genome can also result in unintended effects, which need to be reduced/eliminated by selection, since some of the ways the inserted genes express themselves in the host or the way they affect the functioning of the crop’s own genes are unpredictable. This may lead to the development of unknown toxic/allergenic components, which we cannot analyze for and seriously limiting the selection criteria.

Current testing methods need radical improvements.

Currently, toxicity in food is tested by chemical analysis of macro/micro nutrients and known toxins. To rely solely on this method is at best inadequate and, at worst, dangerous. Better diagnostic methods are needed, such as mRNA fingerprinting, proteomics and secondary metabolite profiling.⁶ However, consuming even minor constituents with high biological activity may have major effects on the gut and body’s metabolism, which can only be revealed from animal studies. Thus novel toxicological/nutritional methods are urgently needed to screen for harmful consequences on human/animal health and to pinpoint these before allowing a GM crop into the food chain.⁷