PURPLE cancer-fighting tomatoes have been genetically engineered by British scientists.
The fruits, which resemble tomato-like plums, have already been shown to extend the lives of cancer-prone mice.
Scientists say they could be on sale within three years – but probably not in the UK because of strict European rules about genetically modified food.
Researchers in Norwich made the breakthrough by inserting two genes from a garden flower into normal tomatoes.
The snapdragon genes caused the fruit to produce high levels of anthocyanins, chemicals that give blackberries and blueberries their deep purple colour.
Research suggests the compounds protect against certain cancers as well as heart disease and age-related degenerative conditions such as Alzheimer's.
They may also combat inflammation, improve vision and hinder obesity and diabetes.
The skin and the flesh of the tomatoes are an intense, deep purple colour.
Scientists mixed powder from freeze-dried purple tomatoes into the food of mice lacking an essential anti-cancer gene.
Normally, the mice would be expected to quickly develop cancer and die.
But animals given the genetically modified tomato supplement lived significantly longer, the scientists reported in the journal Nature Biotechnology.