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[SANET-MG] reply to codex questionnaire



I have enclosed our response to the codex questionnaire on GM crops modified for nutrition and health. The response is long so I have put the reply into two separate mailings, one for each codex question.
Question 1
November 27, 2005
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 [1]. 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 all the transgenic proteins has been carried out [2]. 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 [3]. 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 [4]. 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 [5]. • 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 [6]. • Human milk proteins genes were used to modify maize, supposed to improve human nutrition [7]. • Enhanced seed phytoesterol was achieved by transferring a gene from the rubber tree to tobacco [8]. 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 genes [9]. • Very long fatty acids were produced in Arabidopsis using genes from a tiny alga, a protozoa and a fungus [10]. • Soybean naturally deficient in methionine is being engineering to remedy the amino acid deficiency in free amino acids and in storage proteins [11]. • Soybean was modified with a gene from maize, delta-zein, which is rich in methionine [12]. • Maize was modified with a bacterial gene that provided increased free lysine in cellular pools [13]. • A grape stilbene synthetase was used to modify tomato to reduce lipid peroxidation [14]. • Maize modified with prentyltransferase from barley seeds resulted in a large increase in vitamin E [15]. • 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 [16]. 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 [17]. • 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 [18]. A technique called ion genomics has been developed to elucidate all of the genes involved in mineral nutrition in plants [19]. Iron was fortified in rice seeds by modifying the iron in the seeds using soybean ferritin gene expressed in the seed endosperm [20]. 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 [21]. 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 [22]. The approach may be applied to food crops.

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