The Morton - Pusztai debate on GM food safety
 

Dr Arpad Pusztai's responses to the claims of Dr Roger Morton, that GM foods are well tested and that there is a significant body of scientific literature supporting the safety of these foods, are highly recommended reading, raising many important questions about the adequacy of GM food testing and regulation.

1. A summary of the debate
2. Dr Pusztai's first response -  to Roger Morton
3. Dr Pusztai's second response -  to Roger Morton
4. Dr Pusztai's final response - to Bob MacGregor and Roger Morton
5. Dr Roger Morton's original comments relating directly to the work of Dr Pusztai
6. Dr Morton's original and his 'corrected' bibliographies

The Morton - Pusztai debate on GM food safety began in December 2000 when CSIRO scientist Dr Roger Morton posted (to the pro-GM AgBioView e-mail discussion list) a wide ranging and detailed critique of a document called 'GM myths'. Some of Dr Morton's comments related directly to the work of Dr Arpad Pusztai and to the related issue of the safety of GM foods. In support of his claim that there was substantial evidence of GM food safety, Dr Morton included a bibliography citing 56 separate papers of which Morton said the "vast majority" were "full peer-reviewed publications in journals", and again that, "The vast majority of them do have experimental data to back up their claims."  This provided support for Morton's claim that GM "food has been tested and it is a lie to suggest it has not".

Dr Pusztai's first response to Morton's comments and bibliography, carefully dissected this list of papers to reveal that not only were the vast majority of the items cited not peer-reviewed but that part of the list was actually made up by duplication and even triplication of certain papers. Dr Pusztai showed that amongst Morton's 56 "papers" there were, in reality, only a handful of "full peer-reviewed" animal studies, ie the type of study most directly relevant to testing GM food safety:

"This makes a total of FOUR  PEER-REVIEWED animal study papers.  It is somewhat different from the 56 claimed."

Dr Pusztai also pointed out that a number of relevant published animal studies had actually NOT been inluded in Dr Morton's list, and speculated as to whether, given that they were fully peer reviewed, their exclusion reflected the fact that they did not necessarily support Morton's thesis as to the safety of GM foods. Dr Pusztai concluded, "All in all, if this is the best that an enthusiastic proponent of GM foods can come up with in support of their safety, we are really in trouble."

In his repsonse to Dr Pusztai's comments, "Response to Pusztai and apology", Dr Morton apologised for the duplication of papers which he said had been accidental. Dr Morton also said he had adjusted his list accordingly and that it now contained 53 rather than 56 papers (Morton's revised list). Dr Morton also disputed Dr Pusztai's comments about the number of properly peer reviewed animal studies and claimed that when one included abstracts to meetings and compositional studies this made for a "substantial" number of "publications with actual data":

"I come up with 12 are publications in peer-reviewed journals that definitely report experimental data to back up their results - a little different to Pusztai's figure of 4. Another 8 of them are abstracts to meetings where it would appear from the title the authors are reporting experimental results. Presenting data at a meeting is a form of peer review.   When one considers how few GM crops are in the market place I think 20 publications with actual data is quite substantial. It seems to me that these publications cover the GM technologies that are in use commercially at the moment."

In his further response to Dr Morton, Dr Pusztai pointed out that the revised 53-item bibliography still only contained a very limited number of properly peer reviewed studies of which just 5 were examples of the animal testing of GM foods. In fact, a small number of other peer-reviewed animal studies do exist but were not included in Morton's list, including Pusztai and Ewen's GM potato study published in the Lancet, leading Pusztai to comment:

"Clearly, even though this article and a few others in Domingo's list in Science were most definitely peer-reviewed papers, they obviously did not come up to the pro-GM scientists' standards, as exemplified by the 41 non peer-reviewed references in the original and in the amended list.

I am afraid, even now I and, I guess, a lot of other scientists would regard the contents of these 41 "references" as little more than opinions.  I pick out a few glaring examples at random.  How could articles such as that published in the FDA Consumer magazine (no. 45), the R&D Magazine (no. 48), or Canadian Newswire Oct 25 (no. 52), etc be regarded as superior to the peer-reviewed papers in Domingo's references in Science?"  [emphasis added]

In Morton's repsonse to this, "Dr Pusztai - please read your own paper", Morton interestingly made no further attempt to defend his bibliography, focusing instead on Dr Pusztai's GM pea study, which Morton had included in his revised bibliography of research supposedly supporting the safety of GM foods. Morton has argued that this paper shows no detectable evidence of harm and that its title should have stated this.

A marked change of tone on Morton's part was noticeable in his response, eg he writes, "I am not so sure that I believe you when you tell me Dr Higgins came up with this title", "12% higher fecal N excretion and 4% lower body water content is potentially harmful???  - go on make a case for this then.  Make a case as to how these differences a [sic]potentially harmful. Do now, what you should have done earlier, in the paper", "Go on - I dare you...", etc.

Morton also challenged Dr Pusztai's assertion that the US has till now had, in effect, self-regulation of GM foods, commenting, "I don't think this is true : - any one care to comment?" This drew a supportive response on the AgBioView list from Drew L. Kershen from the law school of the University of Oklahoma. However, within days, and quite coincidentally, came news of a just-published Consumer Federation of America report which appears to support Dr Pusztai's view as to the flimsiness of US regulation, concluding that it "is, at bottom, an elaborate and complicated regulatory charade based upon a few regulatory policies posing as science'' The report was co-authored by Thomas O. McGarity of the University of Texas law school. McGarity specifically refers to the self-regulatory aspect of the US system, saying there is no way of knowing how many manufacturers or importers have applied the substantial equivalence doctrine on their own in order to conclude that they do not need to consult with the FDA prior to marketing biotech foods.[Friday Reuters, January 12 2001, Report Damns U.S. Regulation of Biotech Foods]

Another response to Dr Pusztai came from another AgBioView list subscriber, Bob MacGregor. This also focused on Dr Pusztai's GM pea study. MacGregor stated, "One point that Roger didn't mention has baffled me:  how can one leap to the conclusion that a difference -- even a statistically-significant one -- between intestinal weight with one variety versus another is evidence of harm?"

Dr Pusztai's final responses to MacGregor and Morton deals with these points.

Throughout the debate Dr Morton persisted in excluding from his bibliography Dr Pusztai's fully peer-reviewed Lancet-published study on GM potatoes, not to mention other peer-reviewed studies, as mentioned above, which may raise questions about GM food safety, while including such items as the Royal Society's attack on Dr Pusztai's work (item 49 in Morton's revised list) and many non peer-reviewed general review articles on GM foods and their safety. Ironically too, in his revised bibliography Morton did include Dr Pusztai's GM pea study, as supporting the safety of GM food, even though, as Dr Pusztai points out (first response), the design of this pea study was identical to that of his GM potato work which according to the Royal Society was so badly flawed!

Morton's exclusion of the Lancet paper is very revealing, particularly considering that:

a) the motives and behaviour of the Royal Society have been brought seriously into question, see:
http://www.btinternet.com/~clairejr/Pusztai/puszta_1.html

b) the Royal Society reviewers, none of whom were nutritionists, did not even have access to a full account of Dr Pusztai's methodology, see: http://www.btinternet.com/~clairejr/Pusztai/puszta_1.html

c) Morton's implied reason for exclusion is that the list focuses on 'publications [which] cover the GM technologies that are in use commercially at the moment' BUT if you exclude Dr Pusztai's paper on that basis, you can hardly then include the Royal Society's earlier review of the paper!

Clearly, Dr Morton's claimed rationale for compiling his list of research on GM food safety makes very little sense. But then, as Dr Pusztai so ably exposes in his responses, what we are really dealing with here, as so often with the defence of this technology, is a propaganda exercise in the guise of science and rationality.

The debate:
2. Dr Pusztai's first response -  to Roger Morton
3. Dr Pusztai's second response -  to Roger Morton
4. Dr Pusztai's final response - to Bob MacGregor and Roger Morton
5. Dr Roger Morton's original comments relating directly to the work of Dr Pusztai
6. Dr Morton's original and his 'corrected' bibliographies