THIRD WORLD NETWORK BIOSAFETY
4 July 2005
Dear Friends and colleagues,
RE: EVALUATION OF MONSANTO'S
FEEDING STUDY ON MON863
Further to our mailout of 24
June 2005 ('Scientists express concern over Monsanto's GM maize MON863'),
we are pleased to enclose Dr. Arpad Pusztai's evaluation of Monsanto's
feeding study on rats fed with the GM maize MON863 (Item 1). Dr Pusztai's
evaluation was commissioned by the German government.
MON863 produces a novel Bt toxin (Cry3Bb1) to protect it against corn
rootworm. Despite the many flaws in the experimental design and execution
of Monsanto's study, a number of unexplained and significant effects could
be seen in the rats fed with MON863.
The differences and their potential implications are: increased basophil
count, which may indicate allergic reaction; increases in the number of
lymphocytes and white blood cells, which usually increase in the presence
of infections, cancer, various toxins, and disease states; decreased reticulocyte
count, which is indicative of anaemia; decreased kidney weight, which
points to blood pressure problems; and elevation in blood sugar levels,
which cannot be dismissed as biologically insignificant, given the diabetes
There were also elevated levels of kidney inflammation, liver necrosis,
and other observed changes. Dr. Pusztai says, "It is almost impossible
to imagine that major lesions in important organs (kidneys, liver, etc)
or changes in blood parameters (lymphocytes, granulocytes, glucose, etc.)
that occurred in GM Maize-fed rats, is incidental and due to simple biological
Monsanto also submitted a "follow-up study" in response to the
concerns raised over MON863 by the French expert body that evaluates GMOs,
the Commission du Genie Biomoleculaire (CGB). Dr. Pusztai criticises this
"follow-up study" as inadmissible (Item 2).
This is because Monsanto defended changes in kidney weights by comparing
results from the test animals with rats used in a completely different
study, conducted in a different laboratory, using MON 863 hybrids with
other GM maize samples. In the "follow-up study", the results
of the original MON 863-study was quoted (but not actually re-done) for
comparison. Dr. Pusztai asserts that this inter-experimental comparison
is entirely inappropriate for nutritional evaluation and should be disregarded.
Given the scientific concerns over MON863, it is crucial that further
research is conducted on the GM maize, before any approval for commercialisation
or import is given. Dr. Pusztai's evaluation also highlights the need
for regulators to critically evaluate the studies submitted by applicants
trying to gain approval of their GMOs, as these studies may not always
be to the highest standards and significant differences may be glossed
With best wishes,
Lim Li Ching
Third World Network
121-S Jalan Utama
Evaluation of and Final Report on the summary report of the "13-Week
Subchronic Comparison Study with MON 863 in Rats Preceded by a
1-Week Baseline Food Consumption Determination with PMI Certified Diet
#5002 (Report MSL-18175/Covance Study No. 6103-293)".
This report only deals with the results of the MON 863 feeding study.
Although some of the results of other studies with MON 863 are not confidential
and thus have been available to all, my comments will still strictly be
confined to the feeding study.
The design of the feeding study is not well focussed, with many flaws
and crucial omissions in it and not up to date of what is expected of
such an important study. The experiments are poorly executed in
many instances and the presentation of the results is fragmentary, repetitive,
not well set out and confusing. Although the results are tabulated in
big Tables, the content of these is generally uninformative. There
is a lot of superfluous data presented taking up a great deal of space
but without making any significant contribution to our understanding.
The use of historic values and the comparisons of the test and parental
control diets with an additional six reference diet groups may have some
relevance in commercial production studies but not in a scientific risk
analysis where the comparison must be between the GM corn diet and the
corresponding control diets (see later!). The inclusion of these
additional reference groups only serves to widen the range of the data
in the statistical analyses and thus to reduce the chances of finding
significant differences between the test and control groups. In
any case, these so-called reference groups are only selectively used in
the comparisons when this serves the purpose of the authors. I shall
point and set out these in my detailed comments below.
Diet composition, formulation and other relevant problems:
It is uninformative and unacceptable to describe the preparation of the
diets as done "according to specifications" even if some aspects
of the composition are apparently confirmed by analysis. For example,
MON 863 was reported to contain 11.3% protein while the control line only
9.9%. This was in addition to other compositional differences such
as fibre, etc.
However, in the diets the protein content and other ingredients were equalized
but we were not told where did the extra 12-13% protein, etc. come from
in the control diets. Nothing is given about the equalization and
optimization of the essential amino acid (e.g. lysine, etc) content of
the diets, either. As the diets were apparently stored at room temperature
for the duration of the study we are not told whether the composition
of the diet remained the same throughout or not and whether this was checked
or not. Many sensitive ingredients in the diets could have been
oxidized or otherwise changed to influence the nutritional value of the
diets. There is only a reference to a gravimetric record of dietary
mixing on p. 19 and apparently salt analysis was used as a surrogate for
homogeneity testing! The precise composition of the diets is on
file with the sponsor (p. 17).
It is unclear why the 11% test diet was not supplemented with the parental
line instead of commercial maize. In any case, it is possible that
in the USA the commercial maize samples are already contaminated by GM
maize, such as the glyphosate-resistant NK 603.
A major omission is that, in addition to the parental line control group,
the authors should have used another proper control group in which the
parental line diet was supplemented with the transgene product isolated
from MON 863 maize at the same concentration as it is expressed in MON
863. This should have made it possible to show up any effects due
to the splicing of the Bt gene construct into the corn genome.
Unfortunately both the design and the execution of the feeding study was
For reasons that are not clear at the beginning of the report the starting
weight of the rats is given as 198.4 to 259.8 g for males and 132.1 to
185.3 g for females, all claimed to be within ± 2SD. However, in Appendix
2 (individual body weight data, starting at p. 161) the values are given
as 143 to 186 g for males and 100 to 169 g for females.
In the results it is stated that there were no significant differences
between the test and control groups in the final weight of the rats, their
growth and food consumption. However, these were mean values with
considerable SD values. Moreover, the range of the values considerably
widened during the experiment even though the feed intake of the rats
was reasonably similar. Thus, weight accretion during the experiment
varied between 265 to 370 g for males and 110 to 156 g for females.
Moreover, rats with the highest starting weight occasionally ended up
with the smallest final weight. The most likely explanation for
these erratic results is poor animal management. Unfortunately under
such conditions it is very difficult to make proper comparisons between
the groups because it is difficult to know the reason for the differences
in the results. Thus, claims that this particular GM maize had no
significant effect on rat growth are not supported by the data.
There were further problems with the growth of the rats. The feed
intake of the rats was fairly similar throughout the experiment. However,
the growth was uneven. By week 7 body weight changes became very
erratic and in the last four weeks the rats hardly grew. This meant that
food conversion ratio dropped catastrophically in the last few weeks of
the experiment. No explanation was given. In my opinion the
most likely explanation for this, apart from mismanagement of the animals,
is that there were probably problems with the nutrient composition of
the diets, possibly due to the inclusion of maize in them. However, as
no relevant and precise information is given in the submission about what
actual proteins were included in the diet to make up their total protein
content, nothing further can be said about it.
In some weeks in some of the animals body weight changes were negative
which were then followed by unusually large positive changes. For
example, male rat no. 38612 dropped 53 g in week 11 but then gained 102
g in week 12. These problems again indicate poor animal management, questioning
the value of the work and making it difficult to draw any meaningful conclusions.
Observation of the animals
Although a number of important
organs are weighed (wet but not dry weights), including the liver, kidneys,
etc. no part of the gastrointestinal tract or any of the muscles are weighed
to establish whether the GM maize diet did have any effect on them despite
the fact that there are many papers in the literature that indicate such
Most of the measurements are
mechanistic, conservative and static. Although the results could
be used as a starting point for further more dynamic investigations but
without following up the observed changes in the animals on GM diet the
only thing what we are left with is the possibility of debating the significance
or non-significance of the findings. For example, increased lymphocyte
counts could mean problems with the immune system such as infections,
etc. However, the authors never measured the immune responsiveness
of the rats or the levels of specific humoral or mucosal antibodies to
components of the GM maize and particularly to the expressed Bt toxin
even though that there are published reports in high-class journals that
this could occur. It is also known that changes in basophil counts
could signify changes in allergenicity and IgE levels. Even though
this is a potential major concern with GM diets no attempts were made
to follow it up. And one can go on!
Significant haematology effects:
General comment. There were many significant differences between
the blood constituents of the 33% GM maize diet-fed rats and the REF controls.
However, the possible significance of these is underplayed by the authors
in this case
There are significant differences in WBC, lymphocyte counts, basophil
counts and APPT between rats on 33% GM maize diet vs. control
There are also significant differences in RBC, haemoglobin, haematocrit
(not fully), MCHC, WBC, reticulocytes, lymphocytes, basophils between
rats on GM maize diet vs. REF controls.
RBC, haemoglobin, reticulocytes (at both weeks 5 and 14), basophil counts
were significantly different in GM maize-fed rats vs control.
MCHC, reticulocytes, basophil counts, prothrombin time and APPT in GM
maize-fed rats were all significantly different from those in REF controls.
Protein, albumin, globulin, alanine amino transferase, calcium, chloride,
glucose and creatinine were different in GM maize-fed rats from control
Albumin, alkaline phosphatase, inorganic phosphate, urea were different
in GM maize-fed rats vs. REF controls.
Albumin, globulin, cholesterol, triglycerides were different in GM maize-fed
rats vs. control.
Triglycerides, alanine amino transferase, calcium, inorganic phosphorus
were different in rats given GM maize vs. REF controls.
Urine Chemistry has also shown up many significant differences between
GM-fed rats and controls.
Anatomic Pathology - Necropsy
The description of what was
done is incredibly inadequate. Apparently what was done is that trained
personnel using procedures approved by board-certified pathologists examined,
eye-balled, of the carcass, body orifices, abdominal, thoracic
and cranial cavities and organs/tissues. What follows is summary
Tables of clinical and macroscopic observations (Tables 1,3,4,5), page-after-page
of almost meaningless padding. The only purpose of all this is to
tire out the reader by filling him up with numbers but without providing
them with any information. It is all the more remarkable that if one keeps
reading eventually in Table 6 one gets some, albeit qualitative, information
indicating that the liver, kidneys, stomach and rectum in male rats (somewhat
similar in females) fed the 33% GM maize diet are more affected than the
Tissue preservation - Histopathology
The information given out on
this is that formalin-preserved tissues are embedded in paraffin, sectioned,
stained with haematoxylin and eosin and then examined microscopically.
Very little is revealed about the methodologies used in the study.
Although this imperfectly designed
and executed study has revealed a huge list of significant differences
between the various biologically meaningful parameters of rats fed GM
maize diets and the proper controls or even the REF controls, it would
be impossible for anyone to state that all these statistically significant
differences are also biologically significant. However, the opposite cannot
be said either without proper follow up studies. Some examples and
suggestions were given in this critical appraisal.
First and foremost, a more modest but properly designed and better controlled
and executed experiment would have given us more confidence in the validity
of all the various experimental values and the comparability of the data
of the various experimental groups. As it is, the whole experiment
will have to be repeated. However, the list of significant differences
suggest that the authors' confidence that the genetic modification of
the maize sample has induced no significant changes in the nutritional
value and the biological/immunological, etc. properties of this important
food/feed crop is almost certainly groundless. It is almost impossible
to imagine that major lesions in important organs (kidneys, liver, etc)
or changes in blood parameters (lymphocytes, granulocytes, glucose, etc)
that occurred in GM maize-fed rats, is incidental and due to simple biological
variability. There is an urgent need to move away from simple mechanistic
analytical work that has no hope of describing the dynamic situation that
occurs on feeding GM maize, this new, unpredictable and potentially dangerous
food source to mammalian species.
It is a pity that so much work has brought so little dividend. With more
critical attention to the nutritional/toxicological/immunological works
that had been done and published with GM crops the authors could have
made a real contribution to our understanding of the effects that GM foods
can have on humans and all other important animal species. However, one
thing is certain that as things stand at present I, and probably many
others, would try to make a maximum effort to avoid eating something that
has not been properly tested and therefore may have deleterious effects
on us all.
15 September 2004
Pusztai et al. (2003) "Genetically Modified Foods: Potential Human
Health Effects" in Food Safety: Contaminants and Toxins (ed. By JPF
D'Mello), CABI Publishing, Wallingford, Oxon, UK, pp. 347-372. ISBN
0 85199 607 8
Report on the newly provided data: "Kidney Weight Data from
Two 90 Day Rat
Feeding Studies with Corn Hybrids that Contain Event MON 863"
Company, St Louis, Missouri USA; 20th October 2004.
This contract study has been done with two hybrids of MON 863 by the WIL
Research Laboratory in the USA in response to some of the criticisms expressed
by the French Commission du Genie Biomoleculaire (CGB) concerning the
significant differences in kidney weights found in the original study
between rats that had been fed diets containing MON 863 and its near isogenic
non-GM corn line.
The report presents only some of the results of the feeding study including
kidney weights, final body weights and brain weights of rats fed diets
containing these two hybrid GM lines (+ the original previously obtained
results with MON 863 for comparison) and the near isogenic line diet,
respectively. The feeding study therefore cannot be fully evaluated.
However, as it can be assumed that it was done to a similar design as
the original study with the MON 863 GM corn, all criticisms made to that
study should equally apply to this new study. Thus, the large range of
individual values of the various parameters and the consequently large
SD values make it difficult to establish whether there were any significant
differences between the different groups. For example, kidney weights
of male rats varied between 2.58 to 3.48 g, or 2.72 to 3.66 g, or 2.42
to 3.67 in some of the groups. Without being able to pair and follow through
the appropriate test- and control animals and clearly assign individual
values to individual animals whose starting weight, feed intake, and other
parameters were similar and closely controlled throughout the experiment,
no proper conclusion about the outcome of the feeding study is possible.
Moreover, similar large differences were found in female rats and the
differences in body weights or brain weights of all rats were similarly
large, this study, therefore, has not advanced our understanding whether
the genetic modification of corn as this has been done in the case of
MON 863 or in these two GM hybrids carries any special risks for mammalian
As detailed in my previous main report on MON 863, this type of relatively
crude and insensitive study on organ weights should only be regarded as
starting point in GM food risk assessment. We need more detailed structural,
pathohistological, immunological, hormonal and functional dynamic studies
into organ function, right down to the cellular and subcellular level
to pinpoint whether feeding mammals with GM food/feed represents any nutritional
or physiological stress for the organs and whether it may jeopardize the
health of the animal. There are many such methods in GM- or related fields
it is, therefore, regrettable that the Monsanto scientists have not made
better use of them.
Consultant to GenOk, Tromso, Norway
1st November 2004
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