GM foods: Need for a cautious approach

CULTIVATION OF genetically modified (GM) crops has become popular in countries like the U.S., Argentina and China.

The limited experience of GM foods in India has revealed the associated problems for its widespread acceptance. Corn Soy blend, imported from the U.S. has been distributed in India to provide supplementary nutrition to women and children.

In the U.S. currently 74 per cent of soybean and 32 per cent of maize grown belong to the GM category and are not segregated from their non-GM counterparts. There is a possibility of transgenic events like StarLink maize, which was permitted only for animal feed use and not for human consumption by the regulatory authorities in the USA finding its way to India.

For this reason the Government of India had earlier withheld permission for the import of certain consignments of Corn Soy blend. The StarLink variety of maize contains Cry9c gene or protein consumption of which was reported to have caused adverse health effects consistent with allergenic reactions in humans in the U.S.

The cultivation of StarLink variety of Maize was stopped in the crop season of 2001. During early January 2003, traces of StarLink variety were detected in Japanese imports of Maize from U.S despite certification by the U.S. Agriculture Department Federal Grain Inspection Service. Meanwhile the aid agencies in India like Catholic Relief Services which had earlier filed an appeal with the appellate authorities against the decision of the Government not to allow the import of incriminating consignments, have withdrawn the petition vindicating the Government decision to withhold permission for import.

The case of GM mustard is slightly different. Approval for commercial release/marketing of transgenic mustard and its seed production was sought from the Government of India by the developers of the technology.

The newly introduced protein is expressed at low levels in green tissue and seed. Since unlike the Western countries the Indian population is likely to consume `Sarson ka Saag' it would be of interest to find whether the consumers are exposed to any health risks. Such question of health concerns need to be anticipated by the developers of novel foods through modern biotechnology.

In India the approval for commercial production of genetically modified cotton was given after several years of field trials.

The experience of farmers in Andhra Pradesh in the first year of commercial production is not encouraging. This could have been due to the fact that, though the pest that attacks the cotton was present, perhaps they were not in sufficient numbers to affect the yield and hence the farmers have not experienced a net benefit by cultivating the Bt cotton as compared to the non-Bt cotton.

Cultivation of Bt cotton is thus promising only in years and areas, if there is a major attack by a particular insect. Further, in some major cotton growing areas like Guntur District of AP, foliar sprays of Bacillus thuringensis had been used in the past as natural insecticide. In such areas chances are that foliar insecticide will become less effective.

Actual research studies to find out the type of effects are not available. Also studies are needed to know whether in India, the insects attack the cotton bolls more than the leaves as compared to the USA.

If so, in the Indian varieties, unlike their American counterparts the expression of the Bt toxins should be more in the bolls rather than in the leaves.

There are at least a dozen varieties of transgenic rice cultivars that are on the anvil or under development in the green house.

Among these, the various nutritional improvements such as enhancement of pro vitamin A content, iron, protein and amino acids are considered to be of considerable significance to consumers in India. It is claimed that the transgenic golden rice has great potential for alleviating Vitamin A deficiency in the country. At the current level of intake of rice and the levels of beta- carotene present, it may be able to meet only a small percentage of total recommended daily intakes.

The bio-availability of beta-carotene in the Indian context needs to be adequately studied in view of the non adequate protein and fat stores and intestinal infection among malnourished children. Similarly the bio-availability of iron also needs to be examined.

The Indian Regulatory authorities are accused of taking an unduly long time for approval, indecision, not specifying requirements in advance and lack of transparency in the decision making process.

Even in developed countries it is now well accepted that the methodology used for assessing the risks from the GM foods are not robust or sensitive enough and the molecular and genetic effects of the technology are unpredictable in nature. In fact uncertainty is an entity in the nascent science of Risk Analysis.

Under these circumstances it is prudent to follow a cautionary approach while considering the application of largescale cultivation or import of GM foods.

Ramesh V. Bhat

National Institute of Nutrition, Hyderabad