GE foods are unsafe!
Physicians and Scientists for Responsible
of Science and Technology (PSRAST)
1. General conclusion
Based on both scientific theory and experimental data, it can be concluded beyond
any doubt that genetic engineering of plants and animals may potentially cause them
to unexpectedly contain substances harmful to people who eat them. Scientists cannot
however estimate the probability that harmful substances will be created in any specific
case, because not enough is known about the new field of genetic engineering.Some
of the harmful substances which are known to be possible in genetically engineered
foods could cause allergies or toxic reactions. But, because the knowledge of DNA
is incomplete, genetic engineering of food plants and animals may produce other problems
which scientists have not yet anticipated.
So GE foods are inherently unsafe and we neither have enough knowledge to estimate
the risk for harmful effects nor fully reliable testing methods.
2. Reasons why GE may cause the appearance of unexpected substances
Molecular biologists have shown in the laboratory that the insertion of a gene may
induce unexpected metabolic changes that in the worst case may result in harmful
substances for the following reasons: With presently used techniques, it is impossible
to guide the insertion of a gene. Therefore, it will occur haphazardly in the midst
of the ordered code sequence of DNA. This will perturb the normal close control of
DNA over metabolic processes resulting in unpredictable effects on the metabolism.
This is especially so as, to be successful, the inserted gene has to be inserted
in a region of DNA that is active (most of DNA is inactive, and genes inserted there
will not have any effect).
“The so called promoter that is always included in gene insertion packages, may cause
metabolic disturbances (the most commonly used promoter comes from the Cauliflower
Mosaic Virus “CaMV”). The promoter is added because it is an absolute requirement
to ensure the inserted gene is “read”; i.e. copied into RNA and translated into the
protein for which it codes. In addition, other regulatory sequences called enhancers
are often included as they strongly stimulate gene expression. However, the socalled
enhancers also stimulate the activity of surrounding native genes with potentially
deleterious consequences. The metabolism of the cell may become disturbed in unpredictable
ways. The enhancers may also activate genes that should normally bee inactive. For
example a toxic protein that normally is only expressed in the leaves of a food plant,
may become active in the fruit or seeds used. Moreover, normally, the activity of
genes is the result of a refined regulation of their expression, so no gene is active
longer than needed. The artificially inserted strongly stimulating promoter-enhancer
complex without any coupling to inherent regulatory mechanisms eliminates this delicate
demand/supply regulation. This may have unpredictable effects on cellular functioning.”
Genetic engineering means in most cases the insertion of a gene coding for a protein
foreign to the species. There is no way of knowing what the presence of a foreign
protein will have on the metabolism and functioning of an organism. It may have unexpected
effects in addition to its desired effect including the possibility that it may cause
the generation of a harmful substance.
The effect of a gene is context dependent. In a foreign environment, it may have
unpredictable effects. These effects may be difficult to detect but might in the
worst case generate harmful substances. See “The new understanding of genes”. Most
of the foreign proteins that are used in genetic engineering have never existed in
food. There is no way of knowing beforehand, without extensive food safety assessment,
if it is safe to eat food containing such proteins.
Regulatory genes may inadverently be included in the inserted gene, causing unpredictable
complications (however, with the kinds of genes presently used, this risk is considered
unlikely). The knowledge of regulatory genes is incomplete so there is a risk that
an inserted DNA sequence may possess unanticipated regulatory activities. These genes
regulate the activity of other genes. This might disrupt any of the cellular processes
in which DNA or RNA participate which might result in many kinds of unexpected effects
including the production of harmful substances, (for more details, see The underlying
mechanism involved in the “reading” of regulatory information... [AL]; (part of an
article by John Fagan).) If so called fusion proteins are generated through GE, they
may cause unexpected allergies that may be more allergenic than proteins produced
by the original DNA sequences. Fusion proteins are created by linking pieces of DNA
sequences from two or more sources. The regions where two proteins are joined can
assume conformations very different from those of either of the original proteins.
Furthermore, the likelihood of generating allergenicity in fusion proteins is increased
by the fact that the junctions at which two proteins are fused often assume configurations
that are not common in natural proteins, and are, therefore, more likely to be allergenic.
There are also other reasons why genetic engineering might caused increased problems
with allergens, see Allergens generated in recombinant foods [AL]; by John Fagan.
A special class of hazards might be unexpected effects of known substances. Obvious
candidates are GMOs modified to produce pesticides, substances designed to be toxic.
An example of this is the demonstration of long term toxicity of a strain of GMO
potato by Arpad Pusztai (Lancet 1999 Oct 16;354(9187):1353-4). Conclusion There are
several known ways in which the artificial insertion of a gene may cause unexpected
complications of a kind that never occurs in conventional breeding. Some unexpected
effects have been experimentally verified, see Examples of unexpected effects of
genetic engineering. In addition, because the knowledge about DNA is very incomplete,
there may be effects that cannot be even imagined presently, see “Incomplete knowledge
It took almost 50 years after the introduction of nuclear technology and synthetic
pesticides to appreciate the health and environmental hazards they present. Because
recombinant DNA technology (genetic engineering) is even more complex, and because
we have almost no experience with it, it is reasonable to expect future surprises.
The U.S. FDA and the European Union have been denying any hazards with GE foods.
It is satisfying to find that evidence have been unearthed indicating that this has
been the result of suppression of truth, see footnote.
3. Is it possible today to estimate the risk for appearance of harmful substances
due to genetic engineering?
Risk is the probability that some adverse effect (hazard) will occur in the future.
Of course, no one can predict the future with perfect certainty. The degree of accuracy
of a risk assessment is dependent on how much relevant information is available,
the quality of that information and how well that information is interpreted. Thus,
some risk assessments are more reliable than others.
For example, because insurance companies have many years worth of information about
automobile accidents, they can predict rather well the characteristics of drivers
(using data on age, sex, type of car, and accident history) is most likely to be
involved in an accident. On the other hand, because the physics of only a few major
earthquakes have been monitored with sophisticated seismic equipment, and because
there are debates about what physical signals are important indicators, it is not
yet possible to predict the likelihood of a major occurrence.Specifically, it is
not possible to assess the risk of harm from eating GE food with a high degree of
Genetic control of cell function is not well understood (see footnote ·Incomplete
knowledge of DNA). Not even the DNA sequence of presently marketed genetically engineered
plants is fully known.In order to understand what can go wrong with a system and
to evaluate its potential to go wrong, it is first necessary to understand how the
system works. A cardiologist must understand anatomy, physiology, biochemistry and
pharmacology to diagnose heart disease, predict outcome and prescribe appropriate
Since the genetic control of cell function is an extraordinarily complex system which
is only poorly understood, our comprehension of all that can go wrong when foreign
genes are added to foods, our ability to predict the outcome of eating such foods,
and our ability to design safe GE foods is highly limited.
Furthermore, as anyone who uses a computer knows, the opportunity for malfunction
is increased as systems become more complex and as the manipulation of complex systems
becomes more random and uncontrolled.·Laboratory experiments with GE have
been very limited. For some (but not all) GE foods, some short-term studies have
been conducted on experimental animals. But there are almost no long-term toxicological,
neurological, metabolic, endocrinological, developmental or reproductive studies
of these foods. Such studies are necessary to evaluate the effects of substances
which are slow-acting, have cumulative or reproductive effects. For details see ·”The
approval of Roundup Ready GE-Soy - based on incomplete evidence” and for a suggested
procedure, see ·”Testing the safety of genetically engineered foods” by professor
Human experience with GE foods has been very limited. GE foods have been on the market
for only about five years, so there obviously has been no experience with long-term
exposure to these novel foods. Few controlled short-term human studies have been
conducted on these new foods.
Moreover, since GE foods have not been labeled, there has been no way for scientists
to compare the health of people who have and have not been eating them. In contrast,
humans have had thousands of years of experience with naturally occurring foods,
and the conditions under which they pose hazards (e.g., eating solanine in green
potatoes) are well-known. The problems of risk assessment per se have been further
aggravated by the way regulatory agencies have been handling the GE food issue, see
footnote: Unsatisfactory handling by regulatory agencies.
There is no scientific knowledge at all that makes it possible to estimate how likely
it is for harmful substances to be generated in GE foods. But we can definitely say
today that there is no scientific basis for maintaining that harmful substances may
not appear or are very unlikely.
Problems with food safety testing Safety testing of GE foods is problematic because
genetic engineering may give rise to unexpected and unpredictable substances. It
is illuminative to compare with a closely related field, the testing of medical drugs,especially
as there is an extensive experience of the reliability of such testing.·On
the basis of knowledge about the chemical properties of a medical drug, it is possible
to predict, to a quite large extent, what kind of harmful effects might occur.
In the case of GE foods, there is no clue to decide if an unexpected substance may
be toxic, allergenic, carcinogenic, mutagenic or otherwise harmful.·In medical
drug testing, it is possible to expose test objects to several times higher doses
than used clinically. This helps to get an idea of the harmfulness of a drug.
For foods, such a procedure is impossible because it would give rise to nutritional
mbalances. For these reasons, it is considerably easier to detect harmful effects
of a medical drug than of a GE food. Still about 3 percent of drugs released on to
the market have been withdrawn because of unexpected harmful effects that were not
revealed until the drug had been used at a large scale. And about 10 percent have
had so serious side effects that their use has been considerably restricted.
Yet the drug companies have been using the best available methods in the world. Laboratory
animal and human testing has been used as well as long term clinical studies. They
have been applying the tests very rigorously and carefully. This is because the development
of a new drug is very expensive, so a forced withdrawal from the market means a loss
of billions of dollars.
The greatest problem in toxicological testing is to reveal long term harmful effects.
Against the experiential backgound from medical drug testing, it can be confidently
predicted that even most rigorous safety testing of GE foods is likely to fail to
detect long term harmful effects to a considerable extent.
The only way of minimizing the risk of not detecting unexpected harmful effects of
harmful substances is to use long-term testing. As animals are not fully reliable
predictors of food safety for humans, it is necessary to use Physicians and Scientists
for Responsible Application of Science and Technology (PSRAST) long term humhttp://www.psrast.org/defknfood.htman
studies.Strategies for long term testing of GE foods have been suggested by professor
Arpad Pusztai, see “The need for rigorous biological risk assessment” and professor
John Fagan, see Testing the safety of genetically engineered foods.
As experimental long term testing is not sufficient to ensure safety, Fagan has suggested
a monitored premarketing test on a population of about 2.000.000-3.000.000 people
during 2-3 years with close surveillance of its health status. Even with that test
included, he concludes that there will remain a “residual risk” for unexpected long
term damage.These testing schemes are fundamentally different from the superficial
testing that has been presently been accepted for approval of GE foods, see “Substantial
equivalence versus scientific food safety assessment”
Incomplete knowledge about DNA Suppression of truth turning untenable Unsatisfactory
handling by regulatory agencies Published in May 1999. The present version is the
result of an ongoing and not yet completed revision through the contribution from
new co-authors.Latest update: May 12, 2000.
All the authors of this document have, along with several other scientists, signed
an Open Letter demanding that GE foods that have not been tested properly should
be withdrawn from the market (in practice this means all GE foods).
Dr Michael Antoniou M.D., Senior Lecturer in Molecular Genetics, GKT School of Medicine,
King’s College, London, UK
Dr Joseph Cummins PhD, Professor Emeritus in Genetics, University of Western Ontario
London, Ontario, Canada
Dr Edwin E. Daniel Ph.D. FRSC, Professor Emeritus Health Science, Faculty of Health
Sciences, McMaster University, Hamilton, Ontario Canada
Dr Samuel S. Epstein M.D., D.Path., D.T.M&H, Professor of Environmental and Occupational
Medicine at the School of Public Health, University of Illinois Medical Center Chicago,
Dr C. Vyvyan Howard MB. ChB. PhD. FRCPath. Senior Lecturer, Toxico-Pathologist, University
of Liverpool, UK
Dr Bob Orskov DSc, OBE, FRSE, Honorary professor in Animal Nutrition of Aberdeen
University, Macauley Land Use research Institute, Aberdeen, UK
Dr Arpad Pusztai FRSE, Biochemistry&physiology. Retired, formerly at Rowett Institute,
Dr N. Raghuram Ph.D., (Plant Molecular Biology) Lecturer, Department of Life Sciences,
University of Mumbai, (formerly Bombay), India.
Dr Gilles-Eric Seralini PhD, Hab.Dir.Rech., Professor in Molecular biology, University
of Caen, France
Dr Suzanne Wuerthele Ph.D., Toxicologist and risk assessor, Denver, Colorado, ISA
Editor: Dr Jaan Suurkula, M.D. Chairman of PSRAST
“Genetically Engineered Food - Safety Problems” Published by PSRAST www.psrast.org/defknfood.htm
Jaan Suurkula firstname.lastname@example.org , email@example.com