Summary FAQ

 GM Foods

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This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to a nutrition email discussion group.

Until recently, new varieties of plants or breeds of animals could be produced only by 'conventional' methods such as selective breeding within a species, or cross-breeding between related species.

About 20 years ago, a new and completely different method became available--genetic modification (GM). This technique gives biotechnologists a very powerful new tool for significantly changing the nature of our food supply. Biotechnologists can now introduce into plants and animals genes from completely unrelated organisms. This allows the production of foods with characteristics that could not have been achieved using conventional breeding methods. But note that the process of gene transfer is not completely controllable--usually some extra DNA, of unknown function, will be carried over with the gene for the desired trait.

So far, the only foods from genetically modified organisms (GMOs) to be made available for human consumption are plant foods; it will be some time before GM meat will be on sale at the local supermarket.

As yet, few GM crops with nutritional or other quality advantages have made it to the market place; the main benefits of GM crops have been to the producer. Roundup Ready (herbicide resistant) and 'Bt' crops (containing a bacterial gene that is a natural insecticide) are the two best-known such crops. Roundup Ready crops have a gene that allows them to be sprayed with the herbicide Roundup while they are growing (killing only the weeds), while Bt crops produce their own insecticide, reducing the farmer's requirement to spray with pesticides.

Because GM foods will have 'novel' DNA (i.e., new to that plant or animal) and the effects of the novel DNA can't always be predicted, it is very important that safety testing be conducted on each new GM food.  Labelling of GM foods is also essential to give people the choice of buying the GM product or the conventional alternative.

The Australian government has set in place a strong regulatory system for the control of production and availability of GM food in Australia. Safety testing is compulsory, and GM foods must be labelled (if they contain novel DNA or protein). Unlike new conventional foods, all new GMOs must have undergone a stringent testing procedure before they may be grown in this country. However, the public both here and abroad appear to be concerned about how effective regulators will prove to be. Also, the process of producing GM foods is such that unpredictable effects can occur as a result of the modification. This makes safety testing not only essential, but also somewhat problematic, because the biotechnologists do not necessarily know what safety tests are appropriate.

There is also concern about what effects widespread adoption of GM food production might have on the environment. The range of possible effects is large, including direct effects (e.g., non-target, ecologically important insects being killed as a result of eating Bt crops) and indirect (e.g., the food of an environmentally important species being wiped out by spraying with Roundup). Outcrossing of GM plants to related weed species (conferring herbicide resistance on those weeds) is another possible adverse effect, as is a reduction in productivity of the soil. But perhaps the environmental problems of greatest concern are those that cannot be foreseen. Weighed against these problems is the potential for one beneficial effect on the environment when Bt plants are grown--a reduction in the need to spray with pesticides. 

Although the major benefits of GM have so far been to producers, the first GM foods to show possible nutritional advantages have begun to appear. The most promising of these is a variety of GM rice, known as 'golden rice'.

According to its developers, golden rice may have the potential to significantly reduce vitamin A deficiency and iron deficiency. These are two nutritional problems that afflict hundreds of millions of people in developing nations. There is a debate going on among scientists and health professionals about whether or not golden rice will be as successful as its inventors hope. There is much developmental work yet to be done even before field trials of golden rice will be conducted, so its potential value is as yet uncertain.

Although the application of GM to nutrition shows greater potential for benefit to people in developing nations than for those in developed nations, biotechnologists are also working on GM foods that will look and taste the same as foods currently eaten in Western nations, but contain higher levels of vitamins, have fats that are more 'heart-healthy', or other nutrients that should help protect against diseases such as cancer.

All these potentially beneficial GM foods are only in the early stages of development. It remains to be seen if GM technology can make a substantial contribution to improving people's health. It also remains to be seen if the likely nutritional benefits will outweigh the potential for harm, particularly to the environment.

Although attitudes appear to be hardening against GM foods in Europe, and there was a decided 'dip' in the acceptance of GM foods by Australians in the late 1990s, the pendulum in this country seems to swinging back towards a somewhat more relaxed attitude. But public acceptance of GM food is very strongly tempered by its likely effects on the environment. For example, the vast majority of people favour growing nutritionally-superior GM crops only if there is no (or negligible) harm to the environment.

Paralleling the swing in attitude in Europe (particularly) away from acceptance of GM food, there was a plateauing in world production of GM crops from 1999 to 2000.

No-one can be sure of the future for GM food. An eminent scientist has suggested that, rather than being 'for' or 'against' GM foods in general, it may be more appropriate to weigh the risks against the benefits for each new GM food, and only if the benefits greatly outweigh the risks should that food be considered for production.

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[Date Issued: September 2001]

Disclaimer: This material is provided on the basis that it constitutes advice of a general nature only. It is not intended to replace the advice of a physician or a dietitian.