|Image © Greenpeace|
It's not to the credit of scientists that these preliminary, short term (10-day), small-scale (6 animals per treatment) findings were not followed up. Instead, Pusztai was silenced, and the science of GM safety-testing was effectively stifled for years.
Neither GM potatoes nor the snowdrop insecticide Pusztai was investigating have since progressed very much. However, the basis for Pusztai's test, which was the gut-tissue structural changes occurring in rapid response to adverse elements in the diet, has expanded considerably.
Egyptian scientists, Marwa Ibrahim and Ebtsam Okasha, have dared to look at what happens in the digestive tract of rats fed Egyptian conventional corn, 'Ajeeb', into which a bacterial 'Bt' insecticide has been introduced to form MON810:Ajeeb GM corn. This GM maize is already in widespread use, and the conclusions of the authors are much more damning than Pusztai's, but no one seems to have felt the need to panic ... yet.
Both insecticides, snowdrop and Bt, were assumed to be toxic only to insects and to be intrinsically safe, therefore, for human consumption.
Both the Scottish and Egyptian team used the size of the mucus-creating glands in the gut wall as a measure of an emerging protective reaction to adverse elements in the novel diet. Both found evidence of harm in these measurements.
Both teams also looked for the presence of immune system stimulation in the form of increased white blood cells migrating into the gut tissue. Both found evidence of harm in these measurements.
The Egyptian scientists, however, used more rats (10 per treatment) for a longer time (90 days), examined many more tissue and cell-level parameters, and found a lot more signs of ill-health in the GM-fed rats.
They reported, for example, areas in which the finger-like structures which serve to increase the absorptive surface area of the gut-lining had become shortened, flattened, fused, or lost altogether. Several signs of inflammation were noted, and cell-nucleus abnormalities. "Very alarming" was the finding of areas of erosion of the gut surface which could leads to hemorrhage in vulnerable individuals. Areas of "marked disruption, disorganisation, and distortion and shedding" of the gut tissues were evident.
Notably, "No animals expressed any sign of ill health throughout the experiment and no deaths were reported. There were no observable alterations in the animals' behaviour, feed consumption or average weights between the two dietary groups at the start and at the end of the experiment".
It isn't clear how well controlled the trial was with regard to, for example, comparability of the chow formulations or confounding differences in their nutritional or mycotoxin levels. However, the test feed materials seem have come from official sources, and the authors cite supporting evidence for their results from numerous GM feeding studies.
The unanswered question is, of course, what's causing the profound structural disruption?
Digestive health depends on a fine dynamic balance between diet quality (including nutrient profile, fibre and anti-nutrients), microbe composition and correct functioning of the gut tissues and secretions. GM insecticidal food may contain unpredicted nutritional qualities (including unpredicted properties of the GM insecticide itself), it may provide a novel food for the microbes or could genetically transform them with its artificial DNA. The gut handles a huge flow of materials and can quickly succumb to ill-health and dysfunction if its contents are compromised.
Perhaps of most concern is the indication that a standard 90-day feeding trial may not always be long enough for healthy adults to demonstrate overt harm.
So far, no one has tried to suppress the Egyptian paper, but it could happen yet, especially since the EU has plans to commercialise MON810.
It might be a good idea to bring this study to the attention of you MEPs before it gets a chance to cause gut rot in our livestock.
· Stanley W.B. Ewen and Arpad Puztai, 1999, Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine, The Lancet 354, 16.10 99
· Marwa A.A. Ibrahim and Ebtsam F. Okasha,2016, effect of genetically modified corn on the jejunal mucosa of adult male albino rat, Experimental and Toxicologic Pathology 68
· Monsanto GM corn MON810 damaged the intestines of rates - new study, GM Watch 24.11.16
· L. Montagne, et al., 2003, A review of interactions between dietary fibre and the intestinal mucosa, and their consequences on digestive health in young non-ruminant animals, Animal Feed Science and Technology 108