Clinch-Jones CA. Genetically modified foods - safety and regulatory issues. Med J Aust 2000; 173(3): 166.

To the Editor: I would like to further the debate on genetically engineered foods in the Journal and address some points raised by Huppatz and Fitzgerald.¹ They claimed that gene technology is a progression of selective breeding. In fact, genetic engineering involves the incorporation of:

- commercially desirable genes from plants, animals, microorganisms or humans;

- genetic markers, usually genes for antibiotic resistance; and

- DNA promoter sequences, to "switch on" the new genes - in most commercial food crops, these are from the cauliflower mosaic virus, a pararetrovirus of the same taxonomic group as the human hepatitis B virus.

Clearly, genetic engineering bears little resemblance to conventional breeding.

Huppatz and Fitzgerald also claim that genetically engineered (GE) crops have the potential to increase yields. In fact, there have been staggering losses associated with GE cotton and potatoes, and independent analysis of glyphosate-resistant soybeans shows losses of 4%-10%.²

There are claims of increased nutrition. So far, no marketed GE crop has this quality. Vitamin A rice, cited by Huppatz and Fitzgerald, cannot overcome the fact that vitamin A deficiency is caused by poverty and inadequate access to food.

Far from being more sustainable, there are grave concerns about the environmental risks of GE crops.³ As mentioned by Huppatz and Fitzgerald, half of GE crops are resistant to herbicides, usually glyphosate, which is claimed to be "relatively nontoxic". However, glyphosate is lethal to soil microorganisms, spiders and aquatic life. It reduces sperm motility, causes skin reactions, and increases the risk of non-Hodgkin's lymphoma.⁴

Transgenic foods have been approved on the assumption of "substantial equivalence", and not subjected to testing for unexpected contaminants, toxicity or adverse effects of the novel genes. There have been no human feeding studies, and no post-marketing surveillance. However, there are documented human health risks, including antibiotic resistance and allergic reactions.^3,5

Pusztai's warning that viral promoters may be hazardous⁶ is discounted by Huppatz and Fitzgerald, but it is known that ingested viral DNA can be incorporated into host cells.⁷ The cauliflower mosaic virus promoter used in GE crops has a recombination "hot-spot", allowing it to recombine with dormant viruses and the DNA of many species, causing unpredictable gene expression. Cancer, after all, is a disease of abnormal gene expression.⁸

Transgenic foods cannot be assumed to be safe to humans or the environment. "Consumer education" is not "a major factor" in achieving their acceptance. What is needed is independent proof of their safety. This proof should have been obtained long before their commercial release.

1. Huppatz JL, Fitzgerald PA. Genetically modified foods - safety and regulatory issues. Med J Aust 2000; 172: 170-173.

2. Lappe M, Bailey B. Against the grain. London: Earthscene, 1999: 82-83.

3. Anderson L. Genetic engineering, food and our environment, a brief guide. Melbourne: Scribe Publications, 2000.

4. Hardell L, Eriksson M. A case control study of non-Hodgkins lymphoma. Cancer 1999; 85: 1353-1360.

5. Nordlee J, Taylor S, Townsend J, et. al. Identification of a Brazil-nut allergen in transgenic soybeans. N Engl J Med 1996; 334: 688-692.

6. Ewen SWB, Pusztai A. Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine. Lancet 1999; 354: 1353-1354.

7. Schubbert R, Lettman C, Doerfler W. Ingested foreign (phage M13) DNA survives transiently in the gastrointestinal tract and enters the bloodstream of mice. Mol Gen Genet 1994; 242: 495-504.

8. Ho M, Ryan A, Cummins J. Cauliflower mosaic virus promoter - a recipe for disaster? Microb Ecol Health Dis 1999; 11: 194-197.