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[SANET-MG] gm foods nutritional enhancemens
http://www.i-sis.org.uk/codex.phpISIS Press Release 19/12/05
Reply to Questionnaire Codex Guideline for the Conduct of Food Safety
Assessment of Foods Derived from Recombinant-DNA Plants
Professor Joe Cummins
Dr. Mae-Wan Ho
For Independent Science Panel*
Question # 1: In your view, what would be important factors in
determining if a recombinant-DNA plant is to be considered a A
Recombinant-DNA Plant Modified for Nutritional or Health Benefit@, and
as such within the scope of the proposed annex?
Answer: First, it is essential to exclude the evaluation of
pharmaceutical products such as oral vaccines, immune modulating
proteins, hormones, antimicrobials and growth factors from the present
considerations. Such products should be considered separately and
reviewed independently from the current annex; they are inherently
hazardous and require special consideration under a separate annex.
Plants modified for nutritional or health benefit should include only
those with enhanced vitamins, minerals, antioxidants (for example plant
phenolics (flavonoids) known to fight cancer) and enhanced primary
metabolites such as essential amino acids and health promoting reduced
linolenic fats. Recombinant genes derived from a plant used to modify
another plant species should not automatically be deemed safe for
humans. This is highlighted in a recent investigation in which a protein
from bean was found immunogenic when expressed in pea . Specifically,
immunological assessments carried out for the first time on a transgenic
protein revealed that post-translational processing subsequent to gene
transfer into an alien species introduced new antigenicities that turned
a previously harmless protein into a strong immunogen. In addition, the
transgenic protein promoted immune reactions against multiple other
proteins in the diet.
As practically all the transgenic proteins involve cross-species gene
transfer, they will be subjected to different post-translational
processing, and hence they too, will have the potential to become
immunogenic. And yet, none of the transgenic proteins that have been
commercially approved has been tested. This omission is a most serious
public health issue, and the Independent Science Panel has already
called for an immediate ban on all GM food and feed until proper
assessment on the immunogenicity of the transgenic proteins has been
carried out . This should apply all the more so to GM crops coming to
the market that are meant for human consumption.
Nutritional enhancement and traits for improved health may be developed
using conventional breeding or marker assisted selection then those
traits combined with recombinant traits such as herbicide tolerance
and/or insect resistance. Monsanto’s Vistive soybean, for example,
combines natural genes reducing the oil content of linolenic acid, but
also has transgenes conferring the Roundup Ready trait. The transgene
activity is known to affect the precursor pools leading to formation of
trans fatty acids . The point is that when nutritional or health
traits are combined with transgenic ones, the interaction of the two
should be fully evaluated. Interactions between transgenic nutrition and
health traits and other genetic modifications within a cultivar should
be carefully evaluated, as should interactions between conventional
nutritional or health traits with transgenes in recombinant strains with
which they are combined.
A number of nutritional- and health-related transgenic plants are being
developed (see Box). We must ask if these developments provide real
benefits for people, and whether there are safer, cheaper and more
effective alternatives for producing the nutritional/health benefit.
More importantly, in every single case, it is necessary to assess the GM
plant, the transgene and protein for toxicity and immunogenicity, for
reasons given above.
Nutritional and health-related GM crops under development
· Cassava is being genetically modified to enhance activity of an enzyme
that destroys the toxic cyanogenic glycosides . But these compounds,
which release cyanide when eaten, are normally destroyed if the cassava
is adequately processed.
· A sweet protein, brazzien, was produced in GM maize by introducing a
gene from an African plant. The sweetener was proposed for use in the
food industry .
· A synthetic gene for porcine alpha-lactalbumin was introduced into
maize along with a signal peptide from maize for localizing the protein
to the endoplasmic reticulum. The pig-corn was supposed to provide a
more digestible plant protein for humans .
· Human milk proteins genes were used to modify maize, supposed to
improve human nutrition .
· Enhanced seed phytoesterol was achieved by transferring a gene from
the rubber tree to tobacco . The compounds would be used as
cholesterol-lowering foods when food crops are modified.
· Canola was modified as a source of omega-3 fatty acid using fungal
· Very long fatty acids were produced in Arabidopsis using genes from a
tiny alga, a protozoa and a fungus .
· Soybean naturally deficient in methionine is being engineering to
remedy the amino acid deficiency in free amino acids and in storage
· Soybean was modified with a gene from maize, delta-zein, which is rich
in methionine .
· Maize was modified with a bacterial gene that provided increased free
lysine in cellular pools .
· A grape stilbene synthetase was used to modify tomato to reduce lipid
· Maize modified with prentyltransferase from barley seeds resulted in a
large increase in vitamin E .
· Golden rice expresses a daffodil gene to increase beta-carotene, which
is then converted to vitamin A. This modification has now been extended
to Indica rice . The golden rice cultivars do not produce sufficient
beta-carotene to fulfill the human requirement for vitamin A, however.
· Fructans are considered important functional foods because they
promote the growth of beneficial intestinal bacteria. Fructans enhance
mineral re-sorption, decrease cholesterol and hence may help prevent
cardiovascular disease, colon cancer and osteoporosis. Onion fructosyl
transferase was used to modify sugar beet, a crop that does not normally
produce fructans .
· Deficiencies of iron and zinc in food crops are widespread, and
approaches to increasing trace element uptake or increasing trace
element absorption were reviewed including genetic modification . A
technique called ion genomics has been developed to elucidate all of the
genes involved in mineral nutrition in plants . Iron was fortified
in rice seeds by modifying the iron in the seeds using soybean ferritin
gene expressed in the seed endosperm . Some plant species can
utilize zinc from zinc deficient soils, this ability has been studied to
find out whether or not it can be transferred food crops suffering from
deficiency . A polyhistidine sequence was fused to a rubisco
sub-unit by plastid transformation of tobacco. The polyhistidine
sequence specifically binds zinc, which accumulates at low zinc levels
in the culture medium . The approach may be applied to food crops.
Question #2: In order to assist with the identification of additional
safety and nutritional considerations that the assessment of
recombinant-DNA plants modified for nutritional or health benefit may
warrant, please consider the elements listed below and for each of them
provide comments on the need, added value and relevance of addressing
such items given the intent of the modification introduced in such
a) Estimation of potential exposure distribution patterns - how to go
about determining potential exposure distribution patterns in both
target and non-target populations of a country and evaluate the safety
of such exposure in vulnerable groups. Techniques are available using
population dietary intake data that permit modelling of usual intakes
through simulated inclusion of the modified food in exchange for foods
reported to be used the dietary survey. In this regard, lessons can be
learned from modeling of potential intakes resulting from vitamin and
mineral addition to foods;
Answer: Modeling is appropriate but there is no substitute for
controlled trials and investigations, first in animals, and then in
consenting, informed humans. It is essential that the GM foods be
clearly labelled in the marketplace to provide a means of identifying
the GM foods in epidemiological studies as part of post-release
monitoring and risk management.
b) Bioavailability - when bioavailability testing would be advisable and
some considerations of the techniques available for determining
bioavailability of various types of substances;
Answer: Bioavailability should be incorporated into regulatory reviews
of all of the modified plants purporting to enhance nutrition or health.
Bioavailability can be studied using radioactively labeled tracers of
the compounds or elements being studied. Gut cell cultures have been
employed in such studies; approaches to studying bioavailability of
nutrients have been reviewed .
c) Upper limits of safe intake - the need to determine upper limits of
safe intake for the nutrient or bioactive substance, if they are not
already defined, and how to assess the level of exposure according to
population sub-group of the substance or substances in question against
those upper limits;
Answer: Upper limits of elements such as iron are essential because iron
overload in males leads to a condition called hemochromatosis, resulting
in liver dysfunction and cancer. Vitamin A toxicity is linked to birth
defects and toxic side effects in adults. Genetic modification to
provide for deficiency in some geographic areas may therefore create
toxic side effects in areas where the diet for the nutrients is
adequate. The supplemented crops must be clearly identified and efforts
taken to prevent their use without informed consent.
Upper limits for novel supplements such as human milk protein in maize
or pig lactalbumin in maize clearly require full testing. Full tests for
immunogenicity and toxicity must be carried out on all novel proteins,
as stated above.
Safe upper limits of ingestion should be established using pure
nutrients or enzymes and the final foodstuffs, first in animals then in
d) Stability - what is involved in stability testing, and why that is a
component of risk assessment;
Answer: Stability of primary nutrients such as vitamins and minerals are
well established, however the stability of novel proteins such as the
enzymes introduced into the modified crop should be undertaken because
the novel products may create unexpected toxic by-products. The behavior
of these products during food processing and storage must be studied,
and altered products should be subject to toxicity testing.
e) Risk/benefit consideration - what consideration should be given to
the benefit intended to be provided by the modified food in drawing
conclusions from the risk assessment. Benefits may accrue to certain
target groups while at the same time, health risks may be a concern for
others, but also there may be benefits at lower intakes and adverse
effects at higher intakes. Additionally, how strong the evidence is for
the benefits compared to potential adverse effects may need to be
assessed in these circumstances;
Answer: The precautionary principle must prevail in every case.
Consideration must be given as to whether the benefit really exists, and
whether cheaper, safer alternatives exist, given the known risks of
f) Animal feeding studies - when should animal feeding studies be
considered and what types of studies might be useful depending on the
Answer: Animal studies should be undertaken with every modified crop or
in crosses between modified crops and crops bearing genes for nutrients
or health products that have been enhanced using conventional breeding
or marker assisted breeding. It has become common practice to used crude
measures of size to evaluate the outcome of feeding experiments. That is
not acceptable. Full tissue and organ necropsy is required in every case
to detect cell damage and to identify pre-cancerous lesions. In
addition, immunogenic and toxicity tests must also be carried out.
g) Study Design - the design and conduct of studies to obtain reliable,
repeatable data on composition of the modified food with respect to the
intended and potential unintended changes, at the appropriate stages of
crop and food production. In particular, whereas in evaluating
unintended effects comparative data in the raw product is usually quite
acceptable, where an intended change has been introduced, there will
need to be data on the variation in tissue concentration relevant to the
parts of the plant that will be used for food production and data to
show that the content of the substance remains stable with time,
processing and storage. The impact of factors known to affect crop
composition from year to year and by geographical location, soil type
and fertility, etc. may need special attention in the case of intended
Answer: Common stress factors in crops such as water deprivation or
water logging, nitrogen deprivation or over use and temperature stress
all contribute markedly to nutritional value and health related
products. We understand that Codex has pointed to the need for
evaluation of stress in the approval of GM crops. Codex should work to
formalize the most significant stressors and to insure that those
significant stressors are evaluated correctly in the approval of GM
crops slated for the global market. It is certainly clear that GM crops
approved under optimum environmental conditions cannot presume to be
substantially equivalent to GM crops produced under conditions of
h) Any other considerations? Please specify.
Answer: Two major flaws are present in the regulation of GM crops in
North America. The first of these is secretive field tests of GM crops
prior to their commercialization. Bystanders and residents near the test
areas are provided little or no information as to the nature of the
crops being tested. These individuals are exposed to pollen, plant
debris from broken and decayed plant material in dust and from
transgenic products in surface and ground water. The other major flaw is
that the GM food products are not labelled in the marketplace and those
suffering ill effects from consuming the novel materials have no way of
knowing what has injured them. Proper epidemiology of human exposures is
impossible without labelling. GM nutrition and health products must be
labelled and details on field tests must be revealed to the public in full.
*The Independent Science Panel, launched 10 May 2003 at a public
conference in London, UK, consists of dozens of prominent scientists
from 11 countries spanning the disciplines of agroecology, agronomy,
biomathematics, botany, chemical medicine, ecology, epidemiology,
histopathology, microbial ecology, molecular genetics, nutritional
biochemistry, physiology, toxicology and virology
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