Genetically Modified Crops

4. Are genetically modified plant foods safe to eat?

  • 4.1 Could genetically modified plant foods have health effects?
  • 4.2 How should genetically modified food safety be assessed?
  • 4.3 How should genetically modified foods be labelled in the market place?

4.1 Could genetically modified plant foods have health effects?

The question of the safety of genetically modified foods has been reviewed by the International Council of Science (ICSU), which based its opinion on 50 authoritative independent scientific assessments from around the world. Currently available genetically modified crops – and foods derived from them – have been judged safe to eat, and the methods used to test them have been deemed appropriate.

Millions of people worldwide have consumed foods derived from genetically modified plants (mainly maize, soybean, and oilseed rape) and to date no adverse effects have been observed. The lack of evidence of negative effects, however, does not mean that new genetically modified foods are without risk. The possibility of long-term effects from genetically modified plants cannot be excluded and must be examined on a case-by-case basis. More...

4.1.1 Allergens and toxins occur in some traditional foods and can adversely affect some people leading to concerns that genetically modified plant-derived foods may contain elevated levels of allergens and toxins. Extensive testing of genetically modified food currently on the market has not confirmed these concerns. The use of genes from plants with known allergens is discouraged and if a transformed product is found to pose an increased risk of allergies it should be discontinued. All new foods, including those derived from genetically modified crops, should be assessed with caution. More...

4.1.2 One concern about food safety is the potential transfer of genes from consumed food into human cells or into micro-organisms within the body.

Many genetically modified crops were created using antibiotic-resistance genes as markers. Therefore, in addition to having the desired characteristics, these genetically modified crops contain antibiotic-resistance genes. If these genes were to transfer in the digestive tract from a food product into human cells or to bacteria, this could lead to the development of antibiotic-resistant strains of bacteria. Although scientists believe the probability of such a transfer is extremely low, the use of antibiotic-resistance genes has been discouraged.

Methods are now being developed whereby only the strict minimum of transgenic DNA is present in genetically modified plants. Some of these techniques involve the complete elimination of the genetic marker once the selection process has been made. More...

4.1.3 Scientists generally agree that genetic engineering can offer some health benefits to consumers. Direct benefits can come from improving the nutritional quality of food and from reducing the presence of toxic compounds and allergens in certain foods.

Indirect health benefits can come from diminished pesticide use, less insect or disease damage to plants, increased availability of affordable food, and the removal of toxic compounds from soil. These direct and indirect benefits need to be better documented. More...

4.2 How should genetically modified food safety be assessed?

Introduction of new or modified foods, such as genetically modified foods, requires risk analysis since every activity involves risk and in some cases inaction also entails risk.

Several guidelines have been established by national authorities and by the FAO/WHO for food safety assessment of foodstuffs derived from genetically modified plants. In such assessments, the genetically modified food is compared to its conventional counterpart, which is generally considered safe due to its long history of use. They compare to what extent the different types of food can cause harmful effects or allergies and how much nutrients they contain.

Scientists recommend that safety assessment should take place on a case-by-case basis before genetically modified food is brought to the market, since post-market monitoring is more expensive and difficult. The safety assessment process should be transparent, fully documented, and open to public scrutiny, while at the same time respecting the confidentiality of commercial information. More...

4.3 How should genetically modified foods be labelled in the market place?

Consumers may wish to select conventional foods on the basis of several criteria such as methods of production (e.g. organic or fair-trade food), religious principles (e.g. kosher food), or the presence of known allergens (e.g. groundnuts).

Labelling of foods as genetically modified or non-genetically modified may enable consumer choice as to the process by which the food is produced. However, it conveys no information as to the content of the foods, and what risks or benefits may be associated with particular foods. More informative food labeling, explaining how food has been transformed and what the resulting changes in food composition are, could enable consumers to assess these risks and benefits.

The FAO/WHO guidelines (which are still at a preliminary stage) propose to label genetically modified food when they

  1. are significantly different from their conventional counterparts,
  2. contain protein or DNA resulting form genetic modification technology, and
  3. are produced from, but do not contain, genetically modified organisms, genetically modified DNA, or genetically modified protein.


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