Notes on the “Pusztai Affair”

Notes on the “Pusztai Affair”
One of the most controversial events in GM research


Some facts about Dr Arpad Pusztai’s background and, in respect of his research some 10 years ago, his sources of funding, sources of materials, crucial components of the experimental design and overall nature and aims of the project. 

1. Dr Pusztai was awarded a collaborative research grant from the UK government (Scottish Office: Agriculture, Environment, and Fishery Department; grant number FF 818) succeeding against stiff competition. The design of the toxicological studies he conducted would have been extensively peer reviewed and suggested modifications from “experts” incorporated prior to the awarding of the grant. Therefore the experimental design was passed as highly rigorous.
2. Dr Pusztai’s experience in conducting animal feeding studies to assess toxicological and other effects is contained in his published work that employs these techniques (e.g. see Pusztai, A., Ewen, S.W.B., Grant. G., Peumans, W.J., van Damme, E.J.M., Rubio, L., Bardocz, S., 1990. Relationship between survival and binding of plant lectins during small intestinal passage and their effectiveness as growth factors. Digestion 46 (Suppl. 2), 308-316; Pusztai, A., Grant, G., Duguid, T., Brown, D.S., Peumans, W.J., Van Damme, E.J.M., Bardocz, S., 1995. Inhibition of starch digestion by α-amylase inhibitor reduces the efficiency of utilization of dietary proteins and lipids and retards the growth of rats. J. Nutr. 125, 1554-1562; Pusztai, A., Grant, G., Bardocz, S., Alonso, R., Chrispeels, M.J., Schroeder, H.E., Tabe, L.M., Higgins, T.J.V., 1999. Expression of the insecticidal bean α-amylase inhibitor transgene has minimal detrimental effect on the nutritional value of peas fed to rats at 30% of the diet. J. Nutr. 129, 1597-1603). Therefore Dr Pusztai was impeccably qualified to undertake this research.
3. The aim of the award was to develop standard animal feeding trial testing methods for assessing possible unexpected toxicological effects arising from the GM plant transformation process. Dr Pusztai at the time could have been classed as an advocate of the use of GM in agriculture. He was just as surprised as anyone else of the potential adverse health effects that his studies revealed but being a truly objective scientist he reported his data as it stood for the wider scientific community and regulatory authorities to consider. His priorities were clearly with the respect to the heath implications of his studies and not the vested interests of industry or government.
4. The research grant held by Dr Pusztai was a collaboration between himself and a group at the University of Durham. The GM plant production expertise was provided by the University of Durham end of the collaboration. The University of Durham generated, cultivated and provided all the GNA GM potatoes used in the tests (Gatehouse AMR, Down RE, Powell KS, et al. Transgenic potato plants with enhanced resistance to the peach-potato aphid Myzus persicae. Ent Exp Appl 1996; 79: 295-307).
5. The trials conducted by Dr Pusztai consisted of 4 feeding groups of rats. Each group was fed the following (i) normal, parental line of potatoes, (ii) normal, parental line of potatoes spiked with GNA, (iii) normal, parental line of potatoes spiked with Con A and (iv) GNA GM potatoes. In all other respects the diets were equivalent. So if there was any inadequacy in the GNA GM potato feeding group this would have been the same in all groups and therefore a constant. Some have commented that “feeding growing rodents raw potato would cause serious damage to their growth”. However, this is, in fact, a non-argument, since raw potatoes were fed to all experimental groups and would therefore have been expected to produce adverse effects even in the negative non-GM potato feeding group.
Only 2 groups showed adverse effects; (i), those fed the Con A spiked normal potatoes, which was as expected for a known toxin and therefore acted as a good positive control. This result in combination with the lack of adverse effects with the non-GM and non-GM plus GNA feeding groups confirmed the soundness of the overall experimental design; (ii), those fed the GNA GM potatoes implying that the GM transformation process (tissue culture plus gene insertion procedure) had produced a line of potato with unexpected toxic effects.
In conclusion, the experimental design by Dr Pusztai was appropriately internally controlled and therefore consistent. The studies used the best materials and knowledge made available to him by his collaborators. The results obtained are therefore highly significant and remain extant.

Ian Panton

Article featured on the Feeding the World Conference blog


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