There have been many attacks made by proponents of genetic engineering on Ignacio Chapela and his co-author following publication in the journal Nature of their paper on the presence of transgenic corn in  Mexico (Nature Vol. 413, 27 Sep 01). Amongst these was a letter from leading Fellow of the Royal Society,  Prof Tony Trewavas which was posted on the pro-GE listserv AgBioView. []

Prof Trewavas did not confine his attack to Chapela alone but drew parallels with what he claimed to be the failings of other scientists including Dr Arpad Pusztai. Trewavas also attacked the Union of Concerned Scientists stating:

"...we should ask whether membership implies that they (members of the Union of Concerned Scientists) are free to fiddle any data they like in the greater cause"

having previously stated:

"....because Pusztai is or was a member ...."

The implication appeared clear and Arpad Pusztai, who as he says himself "has never belonged to any political party or pressure group", wrote to Trewavas accordingly,

"What you implied about me in your piece "commentray (sic) on Chapela" under the pretext of a scientific debate is an all time low from a senior scientist."

Trewavas has subsequently denied that he intended any such implication and wrote to AgBioView accordingly appending a letter he had written to Chemistry & Industry criticising Puszai's work. []

Below is the corrspondence arising out of the Trewavas attack and Arpad Pusztai's commentary on it and Trewavas' Chemistry & Industry letter.

Arpad Pusztai's comment on the correspondence:

It appears to me that these exchanges between pro-GM believers like Tony Trewavas and sceptics like myself do not lead very far (see my letter to Robert Mann).  I have been trying to correct the views and assertions by these pro-GM people and the best interpretation I can put on my lack of success with them is that they do not want to understand what I say.  Even the Lancet paper is always, intentionally misinterpreted.  The old red herring that we compared two substantially not equivalent lines of potatoes, i.e. GM vs. parent lines, keeps cropping up again and again despite the fact that in the Lancet paper it is stated unequivocally that ALL diets contained the same amount of protein and energy.  This was relatively simple in this experiment because the line of GM potato (line 71) and the parent potatoes
contained exactly the same amount of protein.  I am at a loss to understand that senior scientists cannot understand such a simple statement. The other red herring thrown in by Tony Trewavas is that I must belong to wicked organizations such as the Union of Concerned Scientists or I-sis and therefore I must have an "agenda" which makes me anti-GM.  I have been saying all along and hundreds of times that I am an independent scientist and do not belong to any organization, still it keeps coming back.  Not that I have anything against these organizations, they are fine but I do not want to be taken for granted.  I look at the merits of each case and then I make the decision.  I have no blanket disapproval of GM crops but I definitely think on the basis of our work and because they are untested that all first generation of GM crops are potentially dangerous and could show up all sorts of risks.  But by not testing them the industry had managed to avoid finding out awkward facts about them.  You see what happened when we did our GM potato studies.  Thus, there ought to be a moratorium on these first generation of GM crops and then have a major independently funded and transparent research programme to investigate what is wrong with them before we could come back to them and discuss what to do with them.  But I did not need to belong to any organization for coming to this conclusion because, in contrast to many of the pro-GM people, I am not an ideologue.  I hope it is clear?

As Tony Trewavas has put on the AgBioWorld website his former letter to Chemistry & Industry (un-peer-reviewed and therefore only stating his personal opinions), I have to reply to them point by point:

Tony Trewavas has the perfect right to differ very strongly from my assessment of the GM potato work that we had done in the Rowett.  However, in most cases he is wrong in facts.  Thus, when he states that the two GM lines and the parent line potatoes were not substantially equivalent this was only partly correct.  What is important in formulating diets for nutritional comparisons (as I stated this on innumerable occasions, including to him) that the diets must contain the same amount of protein, energy, vitamins, minerals, etc.  As it so happens the GM line (no. 71) and the parent line described in the Lancet paper contained the SAME amount of
protein and were therefore comparable without any protein supplementation. Tony Trewavas said that according to my admission "the claimed effects were tiny".  I am afraid, as he ought to know, tiny is not a scientific term; the differences (effects) are either significant or not.  As he has heard it in at least three of my lectures at which he was present, our data were independently statistically analysed by the Scottish Agricultural Statistics Services by a multivariate analysis and the differences (almost 40) were found by them and not by us.  He is just simply wrong when he talks that we used paired comparisons, etc. In fact in the Lancet paper, if he cared to look again at our Table 1, this should be painfully obvious to him. However, he is quite right, I am not a molecular biologist, statistician or
plant biologist (although I used to be some years ago which is demonstrated by the 20/30 papers I published; some peer-reviewed by Tony Trewavas in the
old days).  However, I have a degree in physiology (including nutritional science) and a PhD in biochemistry and forty years of experience and track
record which is attested by the nearly 300 papers I published.  Could he, please, describe his qualifications and that how many physiology/nutrition
papers he has published before I can accept that his comments on a subject far from his own field of experience could be seriously considered?

I am very interested to hear R.J. Williams' views on normal and and diseased human physiology re-visited via courtesy of Tony Trewavas.  As we have also
published widely on the effects of starvation/re-feeding, poor diets, lectins, etc on intestinal mass and structure (please, do a computer literature search with my name as a keyword), when will it be that plant physiologists/molecular biologists, who at best could only be regarded as amateur human/animal physiologists, will realize that reading something may not be as good as actually doing it and gathering first hand experience.  It appears to me that nowadays everybody is a self-proclaimed nutritionist and can, therefore, freely dispense advice to the real professionals.  I think a little bit of humility could come in useful. Again, the assertion that Dr Pusztai is member of the Union of Concerned Scientists.  I do not want to repeat myself but I find this name-calling particularly disturbing.  It is almost like to be called a "commy" in the McCarthy era.

The assertion that "the Ewens (sic!) and Pusztai paper would have been rejected by any reputable plant journal..." is particularly funny.  I think someone ought to tell the pro-GM people that nutritional/physiological/gastrointestinal science papers are not submitted to plant journals.  For statistics, see my comments in the previous para.

I find the remarks in the section on somaclonal variation in potatoes and their effect on the observed changes in gene splicing somewhat disturbing from a plant physiologist/molecular biologist.  Professor Trewavas ought to have known that in potato transformation (as described by lots of papers, including those from the actual lab where it was done and from Monsanto's)one does not go back to the cell culture stage but is done on internodal stem segments (mainly to avoid somaclonal variation).  It is almost embarassing for me to lecture him on this and I certainly do not want to prolong his misery.

I am afraid, I do not want to spend any time on making remarks about testing for substantial equivalence.  There are people much more knowledgeable on
this than I but I suggest for readers to see my review on Incidentally, this was peer-reviewed!

My only comment is that I would still like to hear from anyone that how the pro-GM scientists will test for and analyse something that they do not know is present.  You can test for known components but, unless there is some divine intervention, it may be difficult to do this for unknowns.  I also find it intriguing that GM crops can be tested for allergenicity.  True, if the gene is taken from an allergenic source, one can do this.  But what about if the allergenic history of the gene source is unknown?  We would be happy to hear these methods of allergenicity testing that are, apparently, carried out with GM crops.  Please, tell us about these tests and more importantly, tell the regulators.

I think the assertion in the para that GM crops in the UK contain only one piece of DNA and the resulting protein is so embarrassing that it is painful.  Please, read my review on the above website because I cannot go through all the poor science and falsities in the statements that follow describing the rapid degradation of GM DNA/protein in the gut, processing, etc.  This would take us very far and had been described by many on innumerable occasions.   However, I have to smile about the rather back-handed compliments from Tony Trewavas which attribute such huge effect on the public of my miserly 150 seconds on TV in which I, apparently,
incited people to rebel against the establishment and not to buy any GM food from the supermarkets.  I think the much patronized British public has more
sense than our condescending public figures and scientists give them credit for.  I hope that even Tony Trewavas thinks it a joke when he talks about the impartiality of Sir John Krebs' Food Standard Agency.  However, I again find it incredible that a senior scientist such as Tony Trewavas can quote this rubbish about a billion people eating GM food without any ill effect. If food is unlabelled as it is in the USA, there is no way to monitor who eats what and how much.  He should know how to design a scientific experiment and therefore he ought to know that this cannot be regarded even as a botched experiment without overstating its value.

As I said everything about the professionalism of the FDA in my above quoted review, I am not going to repeat these.  Not a single self-respecting scientist would ever refer to their studies or, more likely, to the lack of their studies.  However, finally I have to say something about Professor Chen's experiments because references to these keep popping up all the time. The last time it was in the Royal Society's February 2002 Report where it occupied a central plank in their vindication of GM foodstuffs and my denigration.  Considering that these studies have never been published in a peer-reviewed journal and at best could be described as a "confidential" draft (as I am told by the Royal Society) "submitted" to an unspecified journal, Professor Chen's work has done absolutely brilliantly in comparison with our Lancet paper which has been peer-reviewed by six referees (five of which accepted it, including if my spies are correct by Professor Trewavas
himself) but are still denigrated by people who themselves have never published a single nutritional/toxicological paper on GM crops but, nevertheless are freely dispensing their opinions dressed up as science. Incidentally, Chen's work was done on GM sweet peppers and tomatoes, and according to his own admission at the OECD Edinburgh meeting, he used our (unpublished) experimental design.

Finally, one thing I must give to Professor Tony Trewavas, even if his views are, in most instances, manifestly wrong, because at least he has the courtesy and courage to appear at meetings where views opposite to his own are aired and discussed.  It also gives us a chance to provide an opportunity for the general public to hear both sides of views on the safety of GM foods because if it depended on most of the pro-GM believers (and the Royal Society who criticised our work but not published it)  they would not have a chance to hear anything else but the praises of this God given gift to humanity via the biotech industry.

Incidentally, I never had a chance to reply to Prof Trewavas' letter in Chemistry & Industry.  Hopefully, this not only gave me such an opportunity to reply but also give a chance to many people to read it.

Arpad Pusztai
07 March 2002

From: Dr Arpad Pusztai []
Sent: 23 February 2002 20:59
Subject: Question

Professor Trewavas,

I shall ask you a simple question and I expect a simple yes or no answer to this:

In your opinion have I fiddled my data?

If you think I have, please state it openly and do no not try to hide behind something like that I do not know.  If you believe that I have not fiddled my data, please, write to AgBioView and state this clearly.  What you implied about me in your piece "commentray (sic) on Chapela" under the pretext of a scientific debate is an all time low from a senior scientist.

Arpad Pusztai

Ps.  I have never belonged to any political party or pressure group and never received financial or other support from any.  Could you state the same in such unequivocal terms?

From: Tony Trewavas []
Sent: 25 February 2002 09:09
Subject: Re: Question

Dear Arpad

No I do not believe at all you fiddled your data.  As I told you when
you lectured here I think you made the mistake of not submitting it
first for publication.  But if you had using lines which were not
substantially equivalent would have sunk it. I believe you signed up
for ISIS and on membership lists you are/were a member of the
Union for Concerned Scientists.  if I am wrong then I will apologise
publicly.  I  have no industrial money or support and my sole political
membership is the Labour Party although a somnolent one since I
have never campaigned.  I wrote a short article to Chemistry and
Industry if I remember published May 2000 where my views on your
work were made public.  I think you made the mistake of announcing
what you thought you had wihtout finding out whether others agreed
with you.  You have to accept responsibility for that decision as we
all do in life.  If I remember in my article I point out that I regard you
as one of the tragedies of science because of your previously
unblemished record including 300 papers, you are a recognised
lectin expert and membership of RSE.  But I also regarded your
interpretation as incorrect.  You will find it all in Chemistry and
Industry.  I had nothing to do with any report on your work by the RS
and was not even a member at the time the report was prepared.

I should add in passing that your belief that I or Noreen Murray or
Bill Hill had anything to do with the refusal of Edinburgh Science
Festival is completely mistaken.  I am afraid a mole passed me
information from FOE of comments of yours to I believe Jean
Sanders in that respect.  Noreen Murray is retired, Bill Hill is Dean
and has no time for such trivia and I was never asked.  I would have
thought that was clear from the fact that I agreed to go to the same
meeting as you as the Botanic Garden.

kind regards

Anthony Trewavas FRS
Institute of Cell and Molecular Biology
Mayfield Road
University of Edinburgh
Edinburgh EH9 3JH
Phone 44 (0)1316505328
Fax 44 (0)1316505392
web site
To view the web site simply click on the address

From: Dr Arpad Pusztai []
Sent: 26 February 2002 23:36
Subject: RE: Question

Dear Tony,

I am relieved to hear that you did not join those people who, like James, in August 1998 tried to spread the rumour that I have never in fact done any GM potato feeding experiments but fiddled my data.  This smear, however, was done away with when the Audit Committee established that we in fact did feeding experiments with GM potatoes.  Unfortunately, the Audit Report was confidential and never published.

I suggest that you should re-read what you had written in the last sentence of the third para in your letter posted on AgBioView: "...we should ask whether membership implies that they (members of the Union of Concerned Scientists) are free to fiddle any data they like in the greater cause".  As you have previously asserted that "because Pusztai is or was a member and has also called for moratoria" many people, including myself, read these two statements together with a clear indication that I fiddled my data in the great cause.  As I cleared up in my previous e-mail and re-confirm it now that I have never been a member of any organization, be it the Union of Concerned Scientists or Isis, I would very much appreciate if you posted a copy of the letter that you just sent to me on the AgBioView website.

I am, as I proudly proclaimed in most of my public talks, an independent scientist (a dying out breed nowadays) precisely because I want to examine all the scientific issues what they are worth and then decide it for myself whether they are right or wrong.  I do not allow it to be prescribed to me by any society, party or individual how I should feel or act.  I am allergic to even the thought of this.  I can perhaps remind you that I, together with hundreds of thousands of my fellow countrymen, rebelled against the views forced on to us by an alien power and fought against them in 1956.  In fact, I fled my homeland and chose to come to this country because in those days this was the best and the freest country in the world.

My "great cause" is and has always been science and scientific truth and veracity.  Yes, I called for a moratorium, not because what other people said but because when I looked at the data with our GM potatoes and compared them with the results of the poor science included in the submissions to ACNFP up till August 1998 that had been done by the biotech companies on the three GM crops already accepted, I was so much horrified that, because of my conscience as a scientist, I had to act and tell people about my concerns.  I have all these submissions by the biotech companies (James was on ACNFP) and one day we could even discuss them if the opportunity arose.  However, I have to tell you that I am sick and tired of when people, be it the most distinguished Fellow of the Royal Society of London, patronizingly try to teach me of my science.  I look at the names of the members of the Working Groups, run a retrieval programme and in no time I can find out whether they have a relevant track record and whether they are truly my peers or not.  I have to tell you that most of those who criticised our work and talked about the flawed design, methodology and conclusions of our experiments, have never done a single nutritional/toxicological experiment and therefore their views are only personal opinions, not looked at or peer-reviewed by anyone who has the necessary professional knowledge.  You know as a senior scientist yourself that in science opinions do not count, they are just "verba volent scripta manent", particularly if the scripta is a peer-reviewed publication in a top journal.  I stand by our results and one by one every single result will be published, I can promise you that.

The main criticism you and others have levelled against me that I spoke first and then published rather than published first and spoke about the results after.  In the very first Edinburgh lecture I and Susan repeatedly asked you whether you saw all the 150 sec of my TV interview or whether you read the transcript of the broadcast.  Eventually you admitted that you neither saw nor read it.  Very respectfully, I put it to you that as a first step I should send you a copy of the transcript and then we can talk about it again.  You see, as I was already gagged eight hours BEFORE the TV interview (see the Hansard record of what James said in both the House of Lords and the Commons Science and Technology Committee hearing), all experimental details that you and others talked about were from the Rowett and not me.  You will see that I kept my words to the Rowett and did not disclose even the identity of the gene in our GM potatoes.  Unfortunately, as a result the Rowett had a field day and could tell the world about our "fictitious Con A experiments" in the full knowledge that I could not contradict them.  Yes, we used Con A as a mitogenic stimulant but that was in the lymphocyte response assays.  You see, little knowledge is worse than no knowledge at all.

Finally, I take your word that neither you nor Noreen Murray nor Bill Hill had a hand in that shameful business of the Edinburgh International Science Festival organizers first agreeing to my talk at the Festival then later using a pretext that I cannot speak proper English and that I have a gruff presentational style, going back on their word.  I am sorry for this whoever has started this rumour and apologise to you for even indirectly putting the blame on you.  As I always admitted although we have differences in our scientific views I respected you for turning up at my talks and listened.  I wish the Royal Society and others who criticised me should have also taken the trouble to come and listen to me.  I think we could now be further on the road to at least seeing how these problems with GM food testing might be attempted to be resolved, if that is possible at all.

Kind regards


From: Tony Trewavas []
Sent: 27 February 2002 08:59
Subject: RE: Question

Dear Arpad

I definitely saw your name on a list published by Isis.  You might
care to check on that.  As I have found in the past and no doubt you
know about it names can be easily transposed onto things we know
nothing about.

you are right I should see the transcript an if you can send me one
that will be valuable.  I am well aware of your history and have
nothing but admiration for those that escaped tyranny.  As I said in
my letter to Chemistry and Industry I do regard the whole affair as a
tragedy largely I am afraid constructed by the media.  And my own
reaction was "there but for the grace of God" because in interviews
you can be caught unguarded and wished that something slightly
different had been said.

I assume you have read First Fruit by Brenda Martineau which deals
with the history of Flavr Savr. She performed many of the safety
tests on the product but ended up totally disillusioned. A gripping

kind regards

Anthony Trewavas FRS
Institute of Cell and Molecular Biology
Mayfield Road
University of Edinburgh
Edinburgh EH9 3JH
Phone 44 (0)1316505328
Fax 44 (0)1316505392
web site
To view the web site simply click on the address

From: Dr Arpad Pusztai []
Sent: 06 March 2002 19:39
Subject: FW: Question

Dear Robert,

Many thanks for doing battles with TT on my behalf.  I am enclosing a copy of my response to his various assertions.  I asked him to post this on AgBioView where his original accusations about me appeared.  As he has never replied I am not sure whether he had done this or not.  I shall look it up.

I think the audicity of these people like TT to criticise experiments which they have no expertise on is really breath-taking.  Incidentally, I hope you still remember that he had written to the Life Sciences solicitor at the NZRC hearing about me and my experiments and that this guy in fact read it out at the hearing.  Needless to say that I did destroy his arguments and him there and then.  Moreover, I have personally explained the basics of nutritional science and our experimental design to TT many times.  Now, he is either stupid or he does not want to understand these things. Briefly:

No nutrition experiment can be carried out (certainly not by a competent nutritionist/physiologist) to compare two diets unless their content of protein, energy, vitamins and minerals is the same.  In the Lancet paper it is clearly stated that all diets were formulated to contain the same amount protein, energy, etc. and only an imbecile could misread this (which apparently includes the RS President, TT and many other great scientists).  By the way, according to the Audit Committee's findings all our potato lines including the parent and the two GM lines were "substantially equivalent" and would have been passed by ACNFP as such.  It was our work which established that although the GM line 71 contained the same amount of protein than the parent line the GM line 74 contained 20% less protein.  However, our Lancet paper experiment was done with line 71 and therefore what the TT's of this world are yapping about is absolute rubbish.  Incidentally, when we did experiments with line 74 what we had to do was simply to supplement that diet with an extra 20% protein and then hey presto one could get on with the experiment.  How do these great "experts" think nutritional comparisons between different protein sources have been done in the past?  No I think they deliberately lie in their "great cause".  I am sick of them!

By the way, I am not sure whether TT has divulged the contents of his letter he wrote to me when I asked him outright whether he thought that I fiddled my data.

Best regards