Some of the best sources of antioxidants are expensive fruits such as blackberries and blueberries, but these purple tomatoes may provide a cheaper option. Using genes from a snapdragon flower, a group led by Cathie Martin at the John Innes Centre in the UK created a tomato with unprecedented levels of anthocyanins, a kind of antioxidant that has been linked to reduced incidence of cancers.

In fact, cancer-prone mice fed a diet of 10 percent powdered purple tomato lived significantly longer than mice fed regular tomatoes, the scientists reported. Martin and her colleagues are studying the tomatoes in greenhouse trials and are planning a health study on human volunteers.