CRUCIAL PAPER 12:
Health Risks of Genetically Modified Foods
Citation: ARTEMIS DONA and IOANNIS S. ARVANITOYANNIS, 2009
Health Risks of Genetically Modified Foods
Critical Reviews in Food Science and Nutrition, 49:164–175 (2009)2
Abstract
As genetically modified (GM) foods are starting to intrude in our
diet concerns have been expressed regarding GM food
safety. These concerns as well as the limitations of the procedures
followed in the evaluation of their safety are presented.
Animal toxicity studies with certain GM foods have shown that they
may toxically affect several organs and systems. The
review of these studies should not be conducted separately for each
GM food, but according to the effects exerted on certain
organs it may help us create a better picture of the possible health
effects on human beings. The results of most studies
with GM foods indicate that they may cause some common toxic effects
such as hepatic, pancreatic, renal, or reproductive
effects and may alter the hematological, biochemical, and immunologic
parameters. However, many years of research with
animals and clinical trials are required for this assessment. The use
of recombinant GH or its expression in animals should
be re-examined since it has been shown that it increases IGF-1 which
may promote cancer.
Extract:
ETHICS
The lasting sceptical and/or ambivalent attitude of Europeans towards
agro-food biotechnology and the continued controversies
about the commercialization of transgenic agro-food products are
illustrative of an ongoing legitimacy crisis. One could
even interpret the stigma on agro-food biotechnology and its products
as testifying to a “robust” societal disapproval: it signals
a lack of trust in scientific institutions and expert systems, and
voices a social response against the reduction of the complexity
of the GMO issue to a solely scientific risk-based problem. Hence,
amove from a merely scientific evaluation towards a
socially more robust one—that addresses precaution and socioethical
issues in a more “sensible”way, whilst making “sense” of
the different stances taken in the GMO debate—is still sought after.
It will be interesting to see whether new controversies show
(triggered, for example, by GMO contaminations or traces of
unapproved transgenic events in nontransgenic produces), how
these will be communicated and developed in the societal climate, and
how they will be interpreted and tackled by, and/or
lead to new adjustments in the now running legal system (Devos et
al., 2007). The comparison of values relevant to GE crops
and foods among EU, Japan, Canada, and the USA is given in Table 2.
CONCLUSIONS
From the review of the toxicity studies concerning GMfoods one might
see that although toxicity can be assessed, the duration
of exposure is too short in order to fully evaluate any potential
disruptions in biochemical parameters and to evidence possible
signs of pathology within the limited subchronic exposure of animals.
Moreover, a larger number of animals should be used
in the toxicity tests. The toxicity tests should comply with the
guidelines for toxicity testing of drugs. It should be emphasized
that since these GM foods are going to be consumed by every human
being they should be tested even more thoroughly
than drugs and more experiments are required in order to study the
possible toxicity and make any conclusions. Tests to determine
how a GM food affects mutagenesis and carcinogenesis should be
conducted as well. Finally, postmarketing surveillance
should be part of the overall safety strategy for allergies,
especially of high-risk groups such as infants and individuals
in “atopic” families. Evaluation of protein allergenicity in man
should also include studies in individuals not only with a history
of allergy but with immunodeficiency as well. The use of recombinant
GH in animals, such as cows or the expression of
GH in animals such as salmon should be re-examined since it may
promote cancer. The results of most of the rather few studies
conducted with GM foods indicate that they may cause hepatic,
pancreatic, renal, and reproductive effects and may alter hematological,
biochemical, and immunologic parameters the significance of which
remains unknown. The above results indicate
that many GM food have some common toxic effects. Therefore, further
studies should be conducted in order to elucidate the
mechanism dominating this action. Small amounts of ingested DNA may
not be broken down under digestive processes and
there is a possibility that this DNA may either enter the bloodstream
or be excreted, especially in individuals with abnormal
digestion as a result of chronic gastrointestinal disease or with
immunodeficiency.
Although intensive scientific effort is currently in progress to
thoroughly understand and forecast possible consequences
on humans, animals, and the environment, it is anticipated that many
years of careful, independent research with animals and
clinical trials will be needed in order to accomplish this assessment.
COMMENT
Note that this is a review paper, not a primary research paper. Nevertheless, we are including it here as one of our "Crucial Papers" because it deserves to be widely read. This is a carefully researched and well-referenced paper which looks at all of the known health risks associated with GM foods. As with most academic publications, the language is cautious, but the authors note a common theme arising from many independent studies of health effects -- the apparently toxic effects of GMOs on internal organs and on the reproductive system. They pick up on the shortcomings of the normal "safety testing" protocols, including the short exposure times experienced by tested animals -- often far too short for GM-related effects to become apparent. They call for testing protocols which are more stringent than drug testing protocols -- on the basis that GM foods are likely (if approved) to be consumed by everybody -- and not just by groups in the population who may be deemed to require "healing." Unusually in a paper of this type, the authors also consider ethical issues, arguing that there is broad societal disapproval of GM crops and foods, based on a lack of trust in scientific institutions and expert systems. The authors argue that in a democracy socio-economic factors should be given much more weight in the regulatory process, since the public will not accept the reduction of the complexity of the GMO issue to a solely scientific risk-based problem.