- British scientist Arpad Pusztai, who
was fired last year from the Rowett Research Institute in Aberdeen, Scotland,
and banned from speaking to the press for a while, told a parliamentary
select committee on March 8 in London he had no regrets about his comments
that led to his dismissal. Humans, he had said, were being used as guinea
pigs in a vast experiment with genetically modified (GM) foods.
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- Pusztai's testimony to the committee
followed headlines in British newspapers screaming that a scientist had
been gagged and his findings suppressed to keep secret that genetically
modified foods threaten health. Conspiracy theories abounded--namely, that
President Bill Clinton had personally pressured Prime Minister Tony Blair
to give biotechnology companies, including Monsanto, a freer rein in planting
GM crops. An admission on March 1 from John Prescott, secretary of state
for Environment, Transport and the Regions--that the British government
has indeed received representations from its U.S. counterpart about GM
crops--did not help.
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- The furor started last August, when Pusztai
released to the media results that he said indicated that rats fed potatoes
genetically engineered to contain a lectin from the snowdrop plant--a naturally
occurring insecticide--had suffered damaged immune systems and stunted
growth of vital organs. The results stood in stark contrast to safety claims
made by biotech companies and to the received wisdom of the harmlessness
of transgenic crops.
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- Four days after his announcement Pusztai,
a renowned scientist who pioneered studies on the effects of lectin, was
suspended. The Rowett institute stated he had muddled his findings. Quietly,
over the ensuing months, Rowett invited a group of independent scientists
to audit Pusztai's work--and the audit found that his conclusions were
indeed erroneous, although it absolved him of the more serious charge of
scientific fraud.
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- Other scientists, though, came to Pusztai's
defense. Two researchers forwarded his data to 21 scientists, who later
issued a memorandum in February that said, "We are of the opinion
... that the consumption of the GM potatoes by rats led to significant
differences in organ weights and depression of lymphocyte responsiveness
compared to controls."
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- A study that criticized the Rowett audit
and confirmed Pusztai's results also got some backing. Done by pathologist
Stanley Ewen of Aberdeen University, a friend of Pusztai's, the work was
examined by Thorkild Bøg-Hansen, a lectin expert from the University
of Copenhagen (and one of the researchers who forwarded Pusztai's results
to others). He concluded that "Dr. Ewen's results clearly showed the
errors in the audit report that followed Dr. Pusztai's suspension from
the Rowett Research Institute. The experiments clearly showed that ...
the GM potatoes caused a major intraepithelial lymphocyte infiltration
similar to inflammatory responses."
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- Vyvyan Howard, a toxicopathologist at
the University of Liverpool and Pusztai supporter, says that the results
showed the main risk of GM food to be "long-term, low-dose toxicity
from subtle changes to the nature of the food chain." He describes
Pusztai's findings as unexpected and not totally attributable to the lectin.
In other words, the genetic modification process itself was causing unpredictable
outcomes. Speculations include virus promoters (mechanisms used to switch
on the inserted genes) and possible unintended switching off of beneficial
genes. "It is precisely this type of finding which means that animal
testing for developmental toxicological effects is essential," says
Howard, who also argues that the "mixture problem" must be addressed
as well. "None of us eat only a single food. The effects of mixtures
to my knowledge have not been addressed," he notes, concluding that
"human volunteer testing would probably be advisable."
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- Tom Sanders of King's College London,
a nutrition expert and a member of the government's Advisory Committee
on Novel Foods and Processes, is not convinced by Pusztai or his supporters.
After reviewing Pusztai's experiments, he maintains that all they definitively
proved was that eating raw potatoes, which are indigestible, is harmful
to mammals-- "something that has been known for many years,"
he asserts.
-
- Sanders also says that carrying out full
pharmaceutical-style testing on GM foods would be impossible, because low-level
poisons ostensibly from GM products would not appear in ordinary toxicological
testing. He also points out that testing for human allergenicity with animals
is not possible. He suggests instead that known allergens be banned for
use in GM food, along with markers used to tell which foods have been modified.
-
- Jim Dunwell of the plant sciences department
at the University of Reading has another point against Pusztai: all potatoes
are not alike, and toxin levels can vary widely between different tubers
before any modification is carried out. "Many assertions that are
made against GM crops are not backed up by sound science," he contends.
-
- Both Sanders and Dunwell note the potential
benefits from genetic modification--food engineered to prevent tooth decay
or to deliver vaccines. Genetic engineering could cut the need for pesticides.
But both also admit its risks. Sanders says that "each crop needs
examination on a case-by-case basis. It is dangerous to extrapolate from
one to another." They also admit that genetic engineering could be
a threat to the environment, especially if tests are not conducted locally.
"The English countryside is not the American prairie," Sanders
comments.
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- In the next few months, the Royal Society--an
independent science academy established in 1660--will complete its own
review of Pusztai's findings and of its own stance on the toxicity and
allergenicity of GM foods. Only then might residents of Britain--and the
rest of the world--move a step closer toward understanding the health threats,
if any. But anyone after a definitive answer will be disappointed--science
doesn't deal in absolutes, and the debate will surely rage on.
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- ___________
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- PETA FIRTH, based in London, described
food scares in Britain in the January issue.
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