Dr Arpad Pusztai Talks on Food for the 21st Century
Organized by The British Hungarian Fellowship
Held at the Polish Hearth Club
South Kensington
7th May 1999, 7.30pm
Prepared by Angela Ryan
Institute of Science in Society
Please note.
I have written this report in the first person in order to preserve the
authenticity of what the speaker said. The speaker has agreed that this is
a true account of what he said.
In the last fifty years there has been an increase in the number of
pesticides we use and we now have to use more and more. There is a need
for biotechnology to overcome this and the costs to the environment and
the farmer. There are four main reasons why this has been on the cards
since the discovery of DNA. There has been an increase in pest resistance
to pesticides and almost all genetically modified plants are in this
category for this does give an advantage. There is a need to improve
yield, cultivation time and growth characteristics and to improve
nutritional value, although no products of this category are yet on the
market, they will be part of the second generation of GM crops.
GM crops are now common place, we have got this technology and
practically everything has been genetically modified now, although in the
UK only three products are on our supermarket shelves. These are GM Soya
which is tolerant to Monsanto’s roundup herbicide. Maize engineered
with the Bt toxin gene made by Novartis and Zeneca’s Flavor Savor,
antisense, puree which ripens very slowly and is convenient for the
farmer.
To make a GM plant you have to breakdown the resistance of the plant in
order to get it to accept the genes you want to put into it. Genetic
engineers have to use tricks to do this, you need a switch - a promoter to
get your gene turned on and off and you have to make the whole thing work
so as you can pick out the cells that have taken up your gene. We use
reporter genes for this, we grow the cells up so that all that have been
successfully transformed can be identified. We use antibiotic resistance
genes to do this. So we don’t just put one gene in, you need an
array. We use plasmids to get it in or we shoot it in with a high
pressured gun. The technique is quite complicated and contains many
elements other than the transgenes themselves. Other things may happen and
the technique is essentially unpredictable. The transgene also go into an
environment where 10’s of 1000’s of other genes from the plant
are being expressed.
Now in our studies we only took two lines to study where both
transformations were done at exactly the same time. The two lines however
became different and this suggests that the transgene got into different
positions in the plant genome. These position effects are not simple to
predict. In order to understand this think of William Tell, the shooting
of an arrow at a target, now put a blind fold on the man doing the
shooting and that’s the reality of the genetic engineer when he’s
doing a transformation. He has no idea where the transgene will land in
the recipient genome.
We made the transformation and had 10-20% success rate which then
reduced to 5% which were promising. Then we regenerated these and selected
again. You have to select all the time. We first grew the transgenic
potatoes in isolation in the lab and then later in open land in Rotterdam.
I must say at this point that we would be eating these potatoes if it
wasn’t for me kicking up such a fuss. This investigation is not about
Dr Pusztai verses James. The British tax payer has spent £1.6m for
this knowledge. You have paid for it. We took all the best scientific
advise. In our case the information would have stopped at the Rowett but I
raised hell.
The regulators were a panel of twelve people, who I care to call
scientific administrators for they have no research opportunity and have
no results. We got the results and even though it has been said that we
shouldn’t have disclosed the findings I still believe it unfair to
use people as guinpigs. I knew what the regulators were getting from
industry. We are told it has been rigorously tested yet only one paper has
been published to do with the safety of eating it. There should be at
least a dozen in my opinion. The facts and reassurances can turn out to be
fake and when the British public’s health is at stake, skepticism is
very important.
In 1995 our group at Durham and the Rowett Scottish group put a bid into
the Scottish office for testing these GM potatoes. These potatoes were
destined for the Scottish and UK market and even though potatoes are a
side dish they still needed to be tested. We won the bid against twenty
seven other groups. Now you have to remember that such bids are peer
reviewed, this is part of the bidding process. Obviously if we were
better, then we must have been reasonably good. We had an objective, to
identify genes that are encoding anti-nutritional factors.
Which genes are bad for insects but OK for mammals? In the case of
potatoes, the insect pests are aphids which eat the leaves and nematodes
which eat the roots. So we tested some of the gene products and then made
an artificial diet for the insects and checked to see if reproduction was
normal and if they were happy or became sick.
The gene must not do anything bad to us. We used rats because they are
mammalian and we used young rats because they show up any ill effects much
more clearly as they are relatively small and vulnerable. There is
sufficient overlap between rat and human to draw on. My institute was
mainly an animal husbandry / animal nutritional institute, that is the
main profile of the Rowett and it has a relevance to human nutrition. I
have recently written a paper on biological testing for the European Union
(it’s interesting, they have sacked me but they still want me to
write science papers for them). We have been testing for 30 years and have
over 50 papers published. This was the first objective and we spent seven
years just to select the appropriate genes to put into the potatoes. So
later on there was a huge contrast, we had a main body of research that
gave us a solid base and we knew the gene product was safe for us to eat.
We had two transgenic lines of potato, 71 & 74 from the same
transformation, we grew them together along with the parent plant. It is
very important to grow the plants together under identical conditions The
comparisons are very important when one is to consider the two lines as
substantially equivalent. Regarding substantial equivalence, there is
actually no need for biological tests, the plants must be of similar
composition and this is how GM crops are being released. They however
cannot be substantially equivalent to the parent because you’ve
introduced new genes, sometimes several. We looked at protein, starch and
sugar content and other things that may be anti-nutritional,
glycoalcholides.
One of the lines contained 20% less protein than the other and we looked
at other things as well and established that these two lines were not
substantially equivalent to their parent. This could not be predicted and
it demonstrates that the unpredictability is not just inherent in the GM
process on a case by case basis but also at the level of every single
transformation created. Our project should have ended right there in my
opinion but we had to develop new testing techniques useful for all GM
plants.
We proceeded and conducted feeding experiments. We fed the rats with the
parent potato, the parent potato plus the protein product of the transgene
and the GM potatoe from both transgenic lines. All experiments were done
under the same conditions, all rats coming from the same line (not clones
but almost as they were highly interbred), all getting the same amount to
eat and all kept in the same environment.
The question was, do they grow normally? And if they are not growing
normally, what is happening to the tissue? One would expect the rats to
grow from 100g to 120g over ten days. Also, did the tissues grow
proportionally? The liver should grow 1g to 1.2g. If the liver wasn’t
growing properly that would suggest toxic effects. The brain size/function
was also significant. We weighed all these tissues and others, wet and dry
weight, and found that many of the tissues were growing
dis-proportionately. What is the mechanisms? We looked at the immune
system, the regulation. You can often see things there that you don’t
see elsewhere there. We did meticulous experiments. We were leading
scientists not bumbling amateurs. I felt concern because these things had
never been tested before and as the experiments went on the worries
started to multiply. There were abnormal effects to the lymphocyte
responsiveness as well. These are genuine effects effecting the immune
system and are not normal.
I made my 150 sec testimony on World in Action because I had facts the
indicated to me there were serious problems with transgenic food. It can
sometimes take 2-3 years to get science papers published and these foods
were already on the shelves. I did indicate my concern and it cost me my
job but I would do it again. Other scientists often ask me why I went
against the code of practice and spoke out before publication in a peer
reviewed journal? My reply is to say we would be eating these potatoes now
and not be discussing the safety of GM food if I would not have done it.
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