A team of British scientists announced this week that they had developed a purple tomato with health-promoting properties. A team from the John Innes Centre, Norwich, produced the tomatoes by integrating genes of snapdragon flower, which is high in an antioxidant anthocyanin thought to have anti-cancer properties.

Anthocyanins, found in particularly high levels in berries such as blackberry, cranberry and chokeberry, have been proven to help significantly slow the growth of colon cancer cells. They are also believed to protect against heart and age-related degenerative diseases, boost eyesight, and may help ward off obesity and diabetes.

The John Innes team is discovering ways to enhance the levels of health-promoting substances in common fruits and vegetables. Tomatoes already contain high levels of beneficial antioxidant compounds, such as lycopene and flavonoids.

Professor Cathie Martin 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 vegetables can be developed that are higher in bioactive compounds.”

Experiments on mice, susceptible to cancer, showed that specimens whose diets were added with the purple tomatoes had a much longer lifespan compared to that breed, who received normal red tomatoes.

Professor Martin said: “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.”