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Oct 16, 2003

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GM foods have not caused a catastrophe so far

There is increasing scientific evidence that genetically modified foods have not posed a threat to the environment or human health, despite widespread plantings over the last eight years.
BY ZAMIR PUNJA

For the past 10 years, debate has raged worldwide over whether genetically modified (GM) foods are safe for human consumption and for the environment. Is the controversy waning? Have GM foods proven their efficacy and safety?

There is increasing scientific evidence that GM foods on the market today have not posed a threat to the environment or human health, despite widespread plantings over the last eight years.

GM foods are crop plants developed using recombinant DNA techniques to achieve expression of a novel trait (due to a novel protein) in the plant. These enhanced traits include resistance to select insect pests, to broad-spectrum herbicides, and to viral and fungal diseases.

During the past two to three years, for example, tomato fruits and rice plants have been enhanced with increased levels of vitamin A and fruits and flowers have been given an extended shelf life.

Plants with novel pharmaceutical compounds, vaccines, and therapeutic proteins, have also been developed. These breakthroughs were achieved using techniques first developed in the 1980s to introduce specific genes from diverse biological sources into the genetic background of a plant. Such techniques are also used to engineer microbes (bacteria and yeasts) to express novel compounds, such as insulin and growth hormone, for human medicine.

The first GM food crop approved in Canada (in 1995) was herbicide-resistant canola. The cultivation of this crop enhanced the farmer's ability to manage weeds without the need for other weed management practices. Herbicide-resistant canola was followed by corn engineered to withstand insect attack by expression of a protein from the bacterium Bacillis thuringiensis (B.t.). Insect-resistant crops allowed farmers to reduce the frequency of pesticide applications needed to control insects.

By 2002, GM crops approved for food use in Canada included canola, corn, soybeans, potatoes, flax, squash, tomato and papaya. For pragmatic reasons of higher yield and reduced costs of production, many farmers adopted herbicide- and insect-resistant GM crops to a record 58 million hectares worldwide in 2002, of which 11.4 million hectares were B.t. transgenics. The total market for transgenic seeds is currently more than $3 billion.

The Canadian food inspection agency oversees the safety assessment of these foods for human consumption, developing and implementing criteria to ensure that these GM foods do not contain detectable levels of potential allergens and toxins and do not differ substantially in nutrient content and other characteristics from the non-GM crop. Any potential negative impacts on the environment of widespread release of GM crops, including weediness, spread of the trait, effects on other non-target species, are also considered. An extensive data package is required for each GM crop, which is submitted by the developer of the GM food to be evaluated.

The rapid utility of techniques to develop GM crops, initially by multinational agrochemical companies, and regulatory approvals granted in the U.S. and Canada in the mid-1990s, frequently with little public dialogue, put GM crops on a collision course with environmental groups, non-governmental organizations, consumer advocate groups, and the organic industry.

The perceived value of the technology, the criteria for assessment of environmental impact, and the regulatory approval process, were challenged. The debate raged over concerns of large agrochemical companies (who accounted for as much as 80 per cent of the new GM crops developed) patenting technologies that could impact future food production. Criticisms were voiced over a lack of adequate testing for potential long-term effects on human health and the environment. The need for non-governmental bodies to assess the safety of GM foods instead of industry sponsors and governmental agencies was reiterated.

Recommendations for a moratorium on the development of GM foods were expounded, and the need for mandatory labelling of GM foods continues to be voiced. While the U.S., Canada, China and Argentina gradually expanded acreages of GM crops and marketed them without the requirement for labelling, member states of the European Union, Australia, and a number of other countries, would not allow the widespread planting of GM crops and legislated against the importation of GM foods.

The resulting trade disputes and complaints are currently under review at the World Trade Organization. In July, 2003, the European Union finally lifted its moratorium on GM foods to include mandatory labelling if GM ingredients in imported foods exceeded 0.9 per cent.

The GM-producing countries have reiterated that there was no scientific evidence to demonstrate any safety concerns relating to GM foods that would preclude the exportation of these crops. Throughout the debate, environmental activists have continued to vandalise field experiments involving GM crops, particularly in Europe, and research funding on GM technology has declined significantly at universities in Germany, France and the U.K.

To protect their interests, the organic industry has invoked a zero tolerance for all GM foods. How did the development and implementation of GM technology invoke such heated controversies and generate polarized public and scientific opinions, precipitating economic and political fallout? As a scientist with research interests in GM foods, I have been involved in debates and discussions on the pros and cons of this technology since 1995. It seems, however, that the flurry of controversy has recently waned, judging from reduced news media coverage, subdued environmental activism, and fewer heated debates. Have concerns over GM foods been pre-empted by worries over recent outbreaks of sudden accute resipiratory syndrome, mad cow disease, and the impending West Nile virus epidemic? Have human stem cell research and cloning superceded earlier concerns over GM foods? Or have consumers resigned themselves to the gradual infiltration of GM ingredients into our daily diets?

Could it be that the large biotechnology firms and governmental agencies have sufficiently addressed consumer concerns over this technology? It does seem that predictions of environmental catastrophes and imminent health hazards and perils from GM foods by anti-GM consumer advocate groups and environmentalists have not materialized. There has been little evidence from peer-reviewed research conducted to date to support enhanced invasiveness or uncontrollable growth of GM crops.

Consequently, are GM foods considered Frankenfoods or a mere product of recent scientific experimentation superceded by centuries of crop breeding experiments conducted by humans?

There have, however, been a number of problems resulting as a direct consequence of GM foods. These include unwanted spread of GM pollen, accidental contamination of GM seed with non-GM seed, poor-yielding GM crops, and unanticipated impact on certain non-target species. The law courts are busy with litigations over patent infringements, failure of growers to acquire appropriate licencing agreements, and disputes over unwanted spread of GM pollen and seeds.

Perhaps the most compelling recent evidence for the lack of harm from GM foods comes from a comprehensive review conduced by the U.S. environmental protection agency, which summarizes data that show B.t. transgenic crops have posed no significant risk to the environment or human health despite widespread plantings over many years. The article in Nature Biotech also describes the extensive tests conducted to reach this conclusion.

Will further reviews of other currently grown and recently developed GM crops provide additional scientific evidence to enhance consumer confidence in this technology? A review process that incorporates sound and current scientific methods to assess the risks and benefits of GM crops should provide information to address continuing concerns from consumer advocate and environmental groups.

Transparency and dialogue, with increased consumer awareness through communication, are essential in this process. Consumers have indicated they want to be empowered with a choice on this issue - this is a social dimension that has for a long time been overlooked.



Zamir Punja is a professor of biology and this year's winner of the Sterling prize for controversy.















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