Editorials

Why all the fuss about genetically modified food?

Much depends on who benefits 

Why are some consumers concerned about food from genetically modified plants? After all, we have been modifying crop plants for centuries by plant breeding. What is new is the recent development of biotechnology that makes it possible to move a single gene from one species to another to produce crops which do not rot so quickly or which are resistant to herbicides or to attacks from viruses, fungi, or insects.

Over the past 20 years we have learnt how to isolate genes from any living organism, introduce the new gene into another organism, and get it to work there. The DNA is isolated and treated with restriction enzymes, which break the DNA down into large fragments about the size of a gene or bigger. These fragments are then forced into strains of bacteria or viruses so that, on average, each bacterium or virus contains one piece of DNA. Growth of the mixture amplifies every piece present, the mixture is plated out, and the bacteria or viruses are then grown up from single colonies. Each colony is then screened for the presence of the particular gene. That is the hardest part, but the result will be a bacterium or virus with the sought after gene.

Growing that bacterial clone then gives milligram amounts of the gene, which can be sequenced and trimmed, with special DNA signals added to it, before it is inserted into the DNA of a bacterium, plant, or animal. Because the genetic code is universal, the gene will work in the new host provided that the right signals have been attached, and in this way we can make human interferon, insulin, or growth hormone in bacteria. In exactly the same way we can now modify plants and animals. ^{1 2}

Genetically modified foods have been entering British supermarkets over the past year. The public has accepted some without hesitationfor example, "vegetarian cheese" and the paste made from genetically modified tomatoes. But others, notably the flour from genetically modified soya beans, have caused controversy. Why? Both the tomato and the cheese offered consumers some advantage: cheese that was acceptable to vegetarians and better tasting tomato puree and sauce. Crucially, the consumer could choose between the conventional and the new product for they were side by side on the shelves. In contrast, flour from genetically modified soya beans offers no obvious advantage to the consumer, but rather to the producer. Since soya derivatives occur in 60% of processed food products, it can't be avoided, and the consumer has no choice. There has been a chorus of protests from consumer groups.³

Genetically modified soya was made by introducing the gene from a soil bacterium so that the plant became resistant to the herbicide glyphosate. Monsanto, the producer of the modified soya, claims that a smaller amount of a safer herbicide is used and that the yield is higher. Herbicide resistant soya has real advantages for the farmer, and this new crop, which accounted for 2% of the US crop in 1996, amounted to 15% in 1997 and is predicted to be 40% in 1998. 

Modified soya is now entering Britain, but retailers cannot offer a choice between a modified and an unmodified product, because genetically modified soya is not kept separate through the production chain in the United States, the major supplier. US farmers are unwilling to segregate the two crops since there is little demand for segregation there and the costs are considerable. The US government considers that attempts to ban the import of soya breach World Trade Organisation agreements, for such products can be excluded only if they are unsafe.

So how do we know if they are safe? Before any genetically modified food can be used in Britain, it needs government approval, and ministers take the advice of the Advisory Committee on Novel Foods and Processes, which I chaired for nine years. This committee, which includes a consumer representative and an ethical adviser, considered this new product to be as safe as conventional soya, and so advised the minister.

So if it's safe, what are the problems? Firstly, consumers are concerned about the environmental impact of these new crops. Are we going to release something we will wish we hadn't? Secondly, there are concerns about some of the antibiotic resistant genes present in some genetically modified plants. But the consumers' biggest concern is about risk, especially in the light of the bovine spongiform encephalopathy epidemic: scientists, and the regulatory processes, are no longer automatically trusted. Risks are assessed differently in medicine and food. We accept quite high risks when we are seriously ill but will not tolerate much risk at all with food.

So what are we to do? Firstly, explain as carefully as possible what is happening and why. Secondly, open up the regulatory process: nothing must be hidden. Thirdly, if possible, offer a choice between the new and the traditional product. Fourthly, label these new foods as helpfully as possible. Finally, it is proving difficult to get agreement in Europe, and Europe may easily fall behind with this new technology, not because of safety or environmental problems, but because of lack of agreement in the European Union.