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[SANET-MG] Genetically modified food and health
Genetically modified food and health – a cause for concern?
By Dr. Elizabeth Cullen
Irish Medical Journal, Volume 100 number 5, May 2007
http://www.imj.ie//Issue_detail.aspx?issueid=+&pid=3655&type=Contents
Sir,
Foods containing genetically modified (GM) ingredients are on sale in
Irish shops. In a survey of soya based foods undertaken by the Food
Safety Authority of Ireland in 2002, over a half of the products tested
contained genetically modified ingredients. Such products included baby
foods and soya desserts. This soya bean contains a foreign gene from a
common soil bacterium linked to cauliflower mosaic virus and petunia
flower control elements. Foods containing GM ingredients may not be
immediately apparent to the consumer, because if the GM ingredients
constitute less than 1% of the product, there is no requirement for such
labelling. It is of particular concern that five samples tested which
contained GM ingredients were labelled as being free of such ingredients.
The availability of these products is a cause of serious concern, as
there are good scientific grounds for the opinion that genetic
engineering of plants designed to be eaten, may be harmful to health. GM
is the process whereby genes that are associated with specific qualities
are transferred to unrelated species by methods not seen in nature.
Genes are segments of DNA that specify the structure of proteins. The
concept of GM emerged at a time when it was still believed that genes
were simple carriers of single traits. However, modern research has
established that no gene works in isolation and that the effect of a
gene is dependent on its interaction with other genes and on its
surroundings. Nevertheless, the insertion of the foreign genetic
material is a random process, and occurs in the absence of normal
promoter sequences and associated regulatory elements, which regulate
the quantity, timing, and duration that each gene is expressed and
subsequent protein interactions. The foreign genes are generally
introduced into plant tissue or into tissue cultures in the laboratory
by either being coated on tiny pellets of gold or tungsten and fired
with a special gun, or else brought in via a microorganism. Indeed, it
can be argued that gene transfer via current GM techniques resembles the
process of viral infection far more closely than it resembles
traditional breeding1. However, the gene insertion process is very
inefficient and requires that an antibiotic resistance marker gene be
coupled to the desired foreign gene. This allows plants cells that have
taken up the foreign gene to be selected by growth in the presence of
the appropriate antibiotic. Once selected, GM transformed cells are
stimulated to develop into fully mature plants. There are potentially
serious health concerns arising from the use of the GM process. Overall
the GM transformation process (foreign gene insertion plus tissue
culture propagation of plant material) is known to be highly mutagenic
and can cause hundreds or even thousands of disruptions to the ordinary
command code sequence in the DNA and may disturb the functioning of the
cell in unpredictable and potentially hazardous ways 2. These new genes
will of course cause the creation of new proteins, which will generally
be alien to the plant, and may, in the worst case, be toxic, allergenic
or otherwise detrimental to heath. The characteristics of a protein with
known allergenicity that would distinguish it from a protein unlikely to
be allergenic are not known4 and further difficulties in the elucidation
of allergenicity, including the availability of allergen-specific
antisera have also been outlined 5.
Approximately 40% of all GM foods on sale contain DNA from a soil
bacterium, which produces an insecticide (Bt toxin), causing the plant
to produce this chemical. As a result, such plants are classified as
insecticides in the US 3. Although animal testing has given rise for
serious concern, only a single peer-reviewed publication of clinical
studies on the human health effects of GM food has been conducted 6.
This study highlighted the possibility that GM material can potentially
pass from the food to bacteria in the gut. These results raise concerns
that antibiotic resistance marker genes present in the GM food could
pass to potential pathogenic bacteria making them refractory to
challenge with certain classes of antibiotics 7.
In the EU, extensive safety testing of GM foods is not required if the
new plant is deemed to be ‘substantially equivalent’ to the parental
plant. This term has no clear definition and no scientific meaning. The
concept itself does not make sense, for if a GM plant is the same as its
original counterpart, there would be no need to develop it in the first
place. The lack of safety testing is disturbing. The regulation of GM
food is currently based on a series of ‘extremely insufficient’
guidelines 8. In the US, there are no compulsory requirements for a
biotechnology company to submit their GM food products to the Food and
Drug Administration (FDA) for assessment. Little research has been
conducted on unintended compositional changes from genetic engineering
9. More research is urgently needed. Issues of chronic toxicity,
carcinogenesis and teratogenesis of genetically engineered foods need
are seriously under-investigated 3. The results of research to date with
animals are disturbing. Immune system damage and proliferation of the
gastric mucosa have been found in rats fed GM potato 10, reductions in
cellular metabolism and changes in the liver and pancreas in rats fed GM
soya 11, allergic reactions and subsequent lung damage in mice fed GM
peas 12 and a preliminary report indicating low-birth weight and
fatalities in rats fed GM soya 13. A Monsanto-sponsored study involving
rats being fed GM maize showed highly significantalterations in blood
cell numbers (higher basophil/lymphocyte/white cell counts; lower
reticulocyte counts) increased blood sugar and decreased kidney weight.
The possibility has been raised 14 that an outbreak of respiratory and
gastro-intestinal illnesses in the Philippines may have been caused by
contact with GM maize. The myalgia illness and mortalities associated
with the consumption of L-tryptophan produced from GM bacteria are well
documented 15 as well as the fears generated when Starlink GM maize
intended for animals was found in the human food chain, with consequent
reports of allergic reactions in consumers. Children will have the
longest exposure to GM food, and their vulnerability has been
highlighted 16.
Acknowledging concerns that much research into possible adverse health
effects from GM foods is needed, the State Government in Western
Australia announced in 2005 that it would fund laboratory testing on
rats to determine the safety of GM food crops. Researchers in the
National Institute of Health, (Bethseda, USA) have stated that "there is
growing concern among the general public and the scientific community,
regarding the potential toxicity of genetically engineered organisms" 4.
To accurately assess any adverse health impacts, it is necessary to have
baseline health data collected prior to the introduction of the food
under surveillance 17. However, little or no such information is
available globally, leading to the situation whereby it is virtually
impossible to link adverse health impacts with the ingestion of GM food.
In addition, the introduction of herbicide tolerant plants in the US has
been associated with increased use of pesticides 18, and Ireland does
not have a register of pesticide-associated illness. The accuracy of
testing of existing foodstuffs for the presence of GM products has also
been questioned. Errors may enter the standard monitoring and the
verification procedures, resulting in the situation that it is not
possible to determine the extent of the uncertainty that a consignment
of food or seed is free of GM products 19. Other limits of post market
assessment in relation to the detection of possible adverse health
effects of GM food, have been outlined5 and include such issues as
treatment being usually symptomatic and undocumented, and in addition,
the potential allergen being seldom identified.
The close links between the GMO industry and the European Food Safety
Authority (EFSA) have been outlined, and this authority appears to take
a less precautionary approach than many of its national members 20.
Recommendations have been made that the EFSA publish the criteria it
would use to assess whether GM food had side effects, as at present it
is unclear20.
It is not acceptable that statutory agencies use guidelines that do not
reflect current health concerns. In addition, health surveillance
systems at present in Ireland are not adequate to detect adverse health
effects should they arise. Aside from the possible adverse health
effects of consuming GM food, containment of GM seed is not possible.
Seeds will spread by wind, and by people and animals.
If planting of genetically engineered crops is allowed in Ireland, we
will leave an irreversible legacy to future generations and will be
guilty of a deliberate betrayal of their interests. Doctors have an
ethical and moral duty to highlight concerns in relation to these
issues, and in the interest of health of present and future generations,
permission to grow or consume genetically engineered foods in Ireland
should be denied.
Acknowledgement
I would like to thank Dr. Michael Antoniou for reading a previous
version of this article
Correspondence:
E Cullen*
Thomastown, Kilcullen, Co. Kildare
E-mail: idea1@eircom.net
www.ideaireland.org
*Irish Doctor's Environmental Assoc.
References
1. Brown P. The Promise of plant biotechnology, the threat of
genetically modified organisms Professor College of Agriculture &
Environmental Science University of California Davis,
http://www.psrast.org/promplantbiot.htm Accessed 29-12-06
2. Latham JR, Wilson AK and Steinbrecher RA, The Mutational Consequences
of Plant Transformation. J Biomed Biotechnol. 2006(2):25376
3. Ewen S Proceedings of the Green Ireland Conference • Kilkenny Castle,
16-18 June 2006
4. Metcalf D. What Are the Issues in Addressing the Allergenic Potential
of Genetically Modified Foods? ‘Environ Health Perspect.2003 Vol 111 1110-3
5. Bernstein JA, Bernstein L, Bucchini L, et al.; Clinical and
Laboratory Investigation of Allergy to Genetically Modified Foods
Environ Health Perspect. 2003 Vol 111:1114-1121.
6. Netherwood T, Martín-Orúe SM, O’Donnell AG, et al.;. Assessing the
survival of transgenic plant DNA in the human gastrointestinal tract.
Nat Biotechnol 2004 22, 204 - 209,
7. Heritage J. The fate of transgenes in the human gut. Nat Biotechnol
2004 22:170 - 172,
8. Pyrme R and Lembcke R In vivo studies on possible health consequences
of genetically modified food and feed – with particular regard to
ingredients of genetically modified plant materials Nutrition and Health
2003 Vol I pp 1-817
9. Pelletier DL Science, law, and politics in FDA's genetically
engineered foods policy: scientific concerns and uncertainties Nutr Rev
2005 Jun;63( Pt1):210-23
10. Ewen SW, Pusztai A, Effect of diets containing genetically modified
potatoes expressing Galanthus nivalis lectin on rat small intestine
Lancet. 1999 Oct 16;354(9187):1353-4.
11. Malatesta M, Caporaloni C, Gavaudan S, et al. Ultrastructural
morphometrical and immunocytochemical analyses of hepatocyte nuclei from
mice fed on genetically modified soybean. Cell Structure and Function
2002 27, 173-180.
12. Prescott VE, Campbell PM, Moore A, et al Transgenic Expression of
Bean -Amylase Inhibitor in Peas Results in Altered Structure and
Immunogenicity Agric. Food Chem., 2005 53 (23), 9023 -9030
13. Ermakova I.V. Influence of genetically modified soya on the birth
weight and survival of rat pups: Preliminary study Presented 10 Oct 2005
National Association for Genetic Security On file
14. Traavik T Filipino islanders blame GM crop for mystery sickness The
Guardian Wednesday March 3, 2004
15. Mayeno AN and Gleich GJ. Eosinophilia-myalgia syndrome and
tryptophan production: a cautionary tale Trends Biotechnol. 1994 12:
346-352.
16. Perr HA Children and genetically engineered food: potentials and
problems J Pediatr Gastroenterol Nutr 2002 Oct;35(4): 475-86
17. Germolec DR, Kimber I, Goldman L, et al, Key Issues for the
Assessment of the Allergenic Potential of Genetically Modified Foods:
Breakout Group Reports Environ Health Perspect 2003 111:1131-1139
18. Benbrook CM Impacts of Genetically Engineered Crops on Pesticide Use
in the United States: The First Eight Years BioTech InfoNet 2003
Technical Paper No 6
19. Heinemann JA, Sparrow AD, Traavik T, Is confidence in the monitoring
of GE foods justified? Trends Biotechnol 2004 ;22(7):331-6
20. FOE 2004 Friends of the Earth Throwing Caution to the Wind
www.foeeurope.org/GMOs/publications/EFSAreport.pdf Accessed 4 January 2007
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