Tomatoes have been genetically modified to reduce the impact of diseases such as cancer.

By expressing genes from snapdragon flowers into tomatoes, scientists from the John Innes Centre have created purple tomatoes high in anthocyanins, which may reduce the impact of chronic diseases such as cancer.

Anthocyanins are naturally-occurring pigments which create the deep purple colour of the tomatoes and have been known to give protection against certain diseases. This was shown when, in the place of red tomatoes, purple tomatoes were added to the diet of cancer-susceptible mice, whose lives were significantly extended as a result.

Professor Cathie Martin, from the John Innes Centre, said: “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.

“This is one of the first examples of metabolic engineering that offers the potential to promote health through diet by reducing the impact of chronic disease. And certainly the first example of a GMO [Genetically Modified Organism] with a trait that really offers a potential benefit for all consumers.”

This forms part of the scientists’ research into ways to increase the levels of “health-promoting compounds” in everyday fruit and vegetables. The scientists hope to use human volunteers to further test the benefits of dietary changes.

Dr Lara Bennett, Science Information Officer at Cancer Research UK, was excited about the findings but offered a word of caution: “It’s too early to say whether anthocyanins obtained through diet could help to reduce the risk of cancer. However, we do know that eating a healthy, balanced diet that is rich in fibre, fruit and vegetables – and low in red and processed meat – is an important way to reduce your cancer risk.”

The John Innes Centre in Norwich is a registered charity and an international centre for excellence in plant science and microbiology. The full study is published in the journal, Nature Biotechnology.