Scientists have created tomatoes genetically modified to produce antioxidants that could help people to improve their diet and health.

The tomatoes are being heralded as the first GM product to offer health benefits to consumers.

The plants were given genes from the snapdragon, a garden flower, which enable them to produce a type of nutrient that may protect against cancer.

When the tomatoes were included in the diet of mice bred to be susceptible to cancer, the animals’ lifespans were significantly extended, according to the British scientists who created the tomatoes.

One idea is that foods like the “super-tomato” could help people meet the government’s recommendation that everyone should eat five portions of fruit and vegetables a day. Using such foods they could eat fewer portions but get the same benefit.

“Most people do not eat five portions of fruits and vegetables a day, but they can get more benefit from those they do eat if common fruit and veg can be developed that are higher in bioactive compounds,” said Professor Cathie Martin, of the John Innes Centre, Norwich, an independent, world-leading research centre where the tomatoes were developed.

Such crops mark a significant shift in the thinking and marketing behind GM foods. So far almost all the crops to have made it to market have been designed to produce chemicals that kill pests or make the plants tolerant to herbicides. This appeals to farmers but has prompted suspicion from consumers, leading to an effective ban on their introduction into Europe.

The new tomatoes are coloured deep purple. This is because, in the snapdragon, the function of the genes is to produce anthocyanins, the pigments that give the flowers their deep colours.

Anthocyanins are also thought to offer protection against certain cancers, cardio-vascular disease and age-related degenerative diseases. There is evidence that anthocyanins may also have antiinflammatory properties, improve eyesight and hinder obesity and diabetes. Tomatoes already contain high levels of the antioxidant lycopene.

The research, to be published in Nature Biotechnology, was part-funded by the Biotechnology and Biological Sciences Research Council, funded by the British government.

“This is one of the first examples of a GM organism with a trait that really offers a potential benefit for all consumers,” said Martin, who now plans to test the tomatoes on humans.

It would, however, take a political rethink for Britain to accept such crops. Europe has held out firmly against GM crops even though they have been widely adopted in North and South America, Asia and Australia. About 280m acres were planted around the world last year.

Pete Riley, of GM Freeze, which campaigns for a ban on GM crops until more is known about them, said the idea of creating GM superfoods was fundamentally flawed. “If you have an ordinary balanced diet there is no need for these weird new vegetables,” he said. “This is just the latest in a series of promised superfoods, none of which have yet made it to the supermarket. They are also very unlikely to benefit the world’s poor who have the greatest need of better nutrition.”

Erik Millstone, professor of science policy at the University of Sussex, said: “The idea that you can improve your health by eating GM foods rather than just getting normal fresh ones is bizarre. What we need is good diets, not high-tech products that let people think they can keep on eating bad diets.”

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