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GMOs and
human health

Risk analysis

There is much confusion about the risks of GMOs in terms of food safety and environmental impact. Regulatory agencies formulate their standards according to science-based assessments of risk. Many consider that decision-making based on science is the only objective way to set policy in a world of diverse opinions, values and interests. Risk analysis is a process consisting of three components: risk assessment, risk management and risk communication.

Consumers need assurance that their food is safe and nutritious

- FAO / 19520 / G. BIZZARRI

Risk assessment

Risk in the context of safety includes two elements: i) hazard, an intrinsic factor (e.g. a biological, chemical or physical agent in, or condition of, food, with the potential to cause an adverse effect on health) that indicates the damage if the event occurs; and ii) the probability or chance that the event will occur. Thus, in relation to chemicals, risk is taken to be hazard x chance of exposure; in relation to quarantine, it is the potential damage by the pest x chance of introduction, etc.

Risk assessment is a scientifically based process consisting of the following steps: i) hazard identification; ii) hazard characterization; iii) exposure assessment; and iv) risk characterization. Hazards, and the chance of those hazards occurring, are thereby studied and models constructed to predict the risk. These predictions can be verified afterwards through, for example, statistical (epidemiological) studies.

The two components of risk both contain a measure of uncertainty, and it is this measure of uncertainty that is the focus of many discussions. For example, there is some doubt as to whether risk estimation methodologies used for related purposes (e.g. pesticide residues in food and pest introduction) have sufficient predictive value for GMOs. In particular, the hazard component of risk analysis is subject to close scrutiny.

Risk management and alternatives analysis

Risk management,5 distinct from risk assessment, is the process of weighing policy alternatives in consultation with all interested parties, considering risk assessment and other factors relevant for the protection of consumers' health and for the promotion of fair trade practices as well as, if necessary, selecting appropriate prevention and control options.

Environmental hazard is probably less easy to quantify than health hazard. It also refers to a common good instead of a private (health) good. In both instances, only long-term experience can show if risk assessment and risk management have been successful. When a sound risk management strategy is applied to environmental problems, as distinct from safety problems, it will begin by describing a problem and the goals, objectives and values to be pursued by solving that problem. An analysis of alternatives is then carried out to consider as many solutions as possible. Rather than narrowing the analysis, this allows the creation of new options or combinations of options. When the benefits and drawbacks of a wider range of solution scenarios can be compared, fuller participation by the concerned society can be better assured.

Risk communication

Risk communication is the interactive exchange of information and opinions among assessors, risk managers, consumers, industry, the academic community and other interested parties throughout the risk analysis process. The information exchange concerns risk-related factors and risk perceptions, including the explanation of
risk assessment findings and the basis of risk management decisions. It is vitally important that risk communication with the public comes from credible and trusted sources.

Safety of GM foods

Foods are complex mixtures of compounds characterized by a wide variation in composition and nutritional value. Although priorities vary, food safety is a concern among consumers in all countries. They would like assurances that GM products reaching the market have been adequately tested and that these products are being monitored to ensure safety and to identify problems as soon as they emerge. Because of the complexity of food products, research on the safety of GM foods is still thought to be more difficult to carry out than studies on components such as pesticides, pharmaceuticals, industrial chemicals and food additives. Through the Codex Alimentarius Commission and other fora, countries discuss standards for GMOs and ways to ensure their safety. One approach, which is being used in assessing the risks of GMOs, derives from the concept of substantial equivalence.

Labelling GM food products: two regulatory approaches

The differences between the United States' and the European Union's perspectives on the labelling of GMOs illustrate some of the issues in the debate.

In the United States, the law requires information on food products to be clear and unambi-guous. Labels are intended to provide meaningful information and to warn and instruct the consumer. Further misleading or unnecessary information is believed to conflict with the right of consumers to be able to choose wisely, and to lessen the effectiveness of essential label information. If GMOs are not different from their traditional counterparts in terms of nutrition, composition or safety, labelling is considered to be unnecessary and perhaps misleading.

In the European Union, labelling is viewed as a way to ensure the consumers' right to know any fact that they deem important; it is a way to give consumers a choice and to inform them about GMOs. The European Union's approach to labelling attempts to reach a compromise among the industrial, scientific and public sectors. In the European Union, the question is not whether to label products of biotechnology, but how to label them.

Substantial equivalence acknowledges that the goal of the assessment is not to establish absolute safety but to consider whether the GM food is as safe as its traditional counterpart, where such a counterpart exists. It is generally agreed that such an assessment requires an integrated and stepwise, case-by-case approach. Factors taken into account when comparing a GM food with its conventional counterpart include:

If the GMO-derived food is judged to be substantially equivalent to its conventional counterpart, then it is considered to be as safe as the counterpart. If it is not, further tests are conducted.

Labelling of GM products

Consumers have a right to be informed about the products they buy. However, whether or not the labelling of GM foods is the most appropriate and feasible way to enable consumers to make informed choices about such food products is the subject of an active and ongoing debate in number of countries. It is also being debated by the Codex Alimentarius Commission. A number of governments have adopted labelling policies and procedures for GMOs, which vary substantially. Farm-to-consumer labelling protocols may pose insurmountable challenges for countries of limited capacity wishing to earn income in international markets.

GMOs and allergens

Genetic modification offers the opportunity to decrease or eliminate the protein allergens that occur naturally in specific foods. With the objective of assuring food safety, greater attention has been given to the potential risks of genetic modifications that may add allergens to the food supply. All products that contain allergens, irrespective of their origin, should be managed similarly - for example by labelling - to ensure the consumers' right to informed choice and the possibility to avoid allergens in foods. The Brazil nut-soybean (see Box) provides an example of how a potential health problem was avoided by testing before marketing. 6

Brazil nut allergens

The possibility of transferring allergens with genetic engineering came to light when a methionine-producing gene from the Brazil nut was incorporated into soybean to enhance its nutrient content. The process was experimented by Pioneer Hi-bred in the United States. The tests conducted by their scientists on allergens, however, confirmed that consumption of the transgenic soybean could trigger an allergic response in sensitive subjects. The nature of the allergic reactions was the same as those triggered by Brazil nuts in sensitive subjects. The company, therefore, decided not to release the transgenic soybean for sale. This particular case was significant in raising awareness about the potential dangers associated with the transfer of genes in the absence of a better understanding of their functional characteristics.

Golden rice and the alleviation of vitamin A deficiency

Recently, rice was genetically engineered by the insertion of three genes (from daffodil and bacteria) that generate enzymes that make the rice grains produce beta-carotene, which can be converted into vitamin A in the body. This transgenic rice produces golden-coloured grains containing enough beta-carotene to meet a person's daily requirement of vitamin A.

The potential to create rice with an enhanced micronutrient content illustrates one way in which genetic engineering can contribute to reducing malnutrition. Vitamin A deficiency, which is widespread in the developing world, can lead to morbidity and blindness and contribute to child mortality.

There are a number of alternative ways to address the problem of vitamin A deficiency, for example promotion of foods that are naturally rich in vitamin A, supplementation and fortification. These technologies are already being used and, although experts debate the merits of each approach, they are found to be effective in treating the illness. The value of GM golden rice therefore needs to be assessed in relation to these other options.

Use of GMOs in solving nutrition problems

The recent announcement that GM crop varieties can be made to produce the precursor of vitamin A (see Box on golden rice) generated considerable anticipation that products from these crops could contribute to solving the serious public health problem of vitamin A deficiency. This anticipation expanded the public debate on the role of GMOs as part of strategies to address global nutrition problems.

Scientists are also experimenting with genetic engineering techniques to prevent food safety problems. For example, genetically modified Bt maize, which is resistant to attacks from toxin-producing fungi, has been associated with decreased mycotoxin contamination. Mycotoxins are carcinogens and they can lead to liver cancer in humans. The fact that fewer feeding punctures from insects are found on Bt maize is thought to mean that there are fewer openings for fungal infection.

5 Source: Report of the 23rd session of the Codex Alimentarius Commission, Rome, 28 June-3 July 1999.
6 This paper is based on information collected up to July 2000. In September 2000, a GM maize containing a gene for a particular strain of Bt, which had been cleared for use as animal feed but not as human food, was found to be commercially available in a human food product. The public regulatory response was rapid, and the longer-term implications of this case are now being determined.

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