Purple GM tomatoes could fight cancer and increase lifespan

(October 30, 2008) A genetically modified purple tomato has been created, that in a pilot test significantly extended the lifespan of cancer-susceptible mice fed the new tomatoes compared to mice fed normal tomatoes.

Scientists took genes from the snapdragon plant (Antirrhinum), inserted them into tomato plants and grew purple tomatoes high in anthocyanins, pigments that occur naturally at high levels in berry fruits
such as the blackberry, cranberry and blueberry. There is evidence that anthocyanins protect against some cancers, cardiovascular disease, age-related degenerative diseases, diabetes, obesity and other illnesses.

Researchers already knew about the health protective properties of anthocyanins that occur in high levels in some edible plants, but were of the opinion that the levels found in many commonly eaten fruits and
vegetables were not high enough to give the best health benefits.

Since most people do not eat the recommended 5 portions of fruits and vegetables a day, they can benefit more if the fruits and vegetables they do eat can be developed higher in bioactive compounds.

Tomatoes are the most logical choice as they are an everyday food already containing high levels of another important bioactive compound, the antioxidant lycopene. Another beneficial antioxidant found in tomatoes and other food plants is flavonoids.

In a pilot test on mice genetically bred to be susceptible to cancer, the group whose diet contained high anthocyanin tomatoes showed a significant extension of life (182 days) compared to the group whose diet contained normal tomatoes (142 days).

Reactions to the study have been cautiously optimistic, with some saying that because this works in mice it doesn't mean it will work in humans. The next step is to do trials with human volunteers to see if anthocyanins obtained through diet could help reduce the risk of cancer. However, it is unlikely that the purple GM tomato would go on sale in in Europe in the near future because of considerable public opposition to GM foods.
 

See also on GMO Compass:

• Overview: GM tomatoes

• Breeding aims: Production of Pharmaceuticals, Enzymes and 'Bio' Raw Materials

Further information:

• Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors (Abstract published in Nature Biotechnology)