disrupts of human hormones
Gilles-Eric Seralini is working on the evaluation of
genetically modified organisms (GMOs) and the toxicity
of glyphosate, the active ingredient in Roundup; and the
comparison between the Roundup formulation product and
glyphosate alone. He addressed the PAN Europe Pesticide
Use Reduction in Europe (PURE) conference in Copenhagen,
and afterwards spoke to John Harvey.
JH: You said
that glyphosate is used on 75% of the world’s GM crops:
is that right?
G-ES: Actually, 99% of GM crops across the world
are designed either to tolerate or to produce
pesticides. Seventy five per cent tolerate pesticides,
mostly Roundup. For example, 90% of transgenic soya is
designed to tolerate Roundup. The other 25% of GM crops
are producing their own insecticide derived from the
biopesticide bacterium Bacillus thuringiensis
(Bt) or insecticides produced in bacteria.
JH: Do you
think that chemicals such as glyphosate, or Roundup, are
being properly tested according to the standard rodent
tests we use for other chemicals?
G-ES: If 99% of GM crops are designed to produce
or tolerate pesticides, then they only help industrial
agriculture rather than organic or extensive farming.
They are tools to help intensive practices.
I was wondering if anyone had given these crops to rats
for the standard three month period. I found there was
no real, good toxicity standard test on rats for these
GM crops. If this has not been done, how can you
guarantee to 450 million Europeans tomorrow that the
crops will be good for health?
My team has
noticed that Roundup disrupts hormones (chemical
messengers) which are modulating the oestrogen
synthesis. Oestrogens are known as female hormones, but
today we know that they are important for bone growth
and testicular function at very low doses. So a
modulation of oestrogen synthesis could account for
sperm decline, increase in cancers and sexual
malformations. So we have to be careful with the
hormonal effects of GM crops and the associated
JH: You used
an enzyme called aromatase. This must be essential for
the healthy functioning of the human body. Why did you
G-ES: Firstly, aromatase belongs to a family of
enzymes which detoxify the body. Secondly, aromatase is
the only enzyme used for the synthesis of sexual
hormones called oestrogens.
So it is very
important to know if an aromatase disruption can affect
sexual malformation, if it can participate in a hormonal
dependent cancer such as breast cancer or any sperm
decline. That is why we chose this crucial and
irreversible enzyme from all the hormone producing
effect did you find that glyphosate or Roundup had on
the function of aromatase?
G-ES: First, we found that very low doses of
glyphosate were toxic on either human embryonic cells,
foetal cells or placental cells. We also found that the
synthesis of hormones was perturbed with Roundup and
this was amplified by the formulation product. It is a
general belief that only the glyphosate active
ingredient in Roundup is toxic. But this general belief
has to be revisited since the formulation product
amplifies the effect.
toxicological rules, one dilutes the effects of the
active ingredient by the formulation products and this
must now be reconsidered because it is probably wrong in
several cases. For example, there are detergents linked
to active ingredients, giving them a toxic effect: it is
this process which has to be reconsidered to evaluate
properly all the active ingredients which are known to
be hormone disruptors.
JH: You said
you had found that very low doses of glyphosate had
caused these effects on aromatase. Are they the kind of
doses that would be used in practical agriculture in the
GE-S: They are about ten to 100 times less than
the doses used by agricultural workers. One has to be
cautious because these are in vitro results but
we do not want to wait for death when the precautionary
principle suggests a need for measures to avoid any
harmful effects on foetuses and children.
JH: The PURE
conference is about reducing the use of pesticides and
applying the precautionary principle; what should the
European Union do about the use of glyphosate and
GE-S: I think that, first of all, GMOs and GM
plants should not be believed to reduce pesticide use,
because they do not do that. Secondly, we have thought
about this question in CRII-GEN (the French committee of
independent research and information on genetic
engineering). We think we need a new body of experts in
Too often, the
only experts designated by governments know the chemical
industry and work with it. We must have independent and
contradictory experts in all the instances where
pesticides, and other industrial products which could
cause harmful effects to humans, are evaluated.
Seralini, President du Conseil Scientifique de CRII-GEN
(Comité de Recherche et d’Informations Indépendantes sur
le Génie Génétique), Universite de Caen, Laboratoire de
Biochimie et de Biologie Moleculaire – IBFA Esplanade de
la Paix, Caen F-14032 Cedex, France, tel: 33 (0) 231 56
56 84, fax: 33 (0) 231 56 53 63,
[This article first appeared
in Pesticides News No. 63, March 2003, page 4]
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