How do Tomatoes Help Fight Cancer?

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Recently, researchers in England announced they had created a new strain of genetically modified tomatoes rich in anthocyanins, with some unexpected health benefits.

Anthocyanins are a class of powerful antioxidant belonging to a group called flavonoids. These compounds, found only in plants, lend rich blue, red, and purple coloring to the flowers, vegetables, and fruits in which they are present.

The research project, based at the John Innes Center in Norwich, was a collaboration with several other European centers, all of which are participating in what has been called the FLORA project – a targeted research initiative focused on exploring the benefits of flavonoids and phenolics (another class of plant-based antioxidant).

Flavonoids in particular, and antioxidants as a whole, are considered important in the prevention of many human diseases – among them cardiovascular disease, and certain types of cancer.

Many people, particularly in developed countries, do not get enough of these important substances in their diets, and the FLORA project is geared towards understanding why flavonoids are so beneficial, and towards exploring ways to increase the consumption of flavonoids in the Western diet.

Research and Results

In this case, the idea was to add anthocyanins to an existing food item—tomatoes—via genetic modification. Tomatoes have somewhat low levels of anthocyanins, making this fruit a good benchmark for engineering a product with a high antioxidant content. The modified tomatoes could then be used to study the effects of the anthocyanin addition.

To create tomatoes rich in anthocyanins, the researchers used genes from snapdragon flowers. The final product? Rich, purple-colored tomatoes, with high levels of anthocyanins.

The next step was to test the results in an experimental animal model. The model used was a mouse P53 knockout – a strain which is vulnerable to developing various types of cancers, including lymphomas. The mice typically die at a young age.

In the experimental model, mice were one of three different diets: a standard diet, a diet including powder from normal red tomatoes, and a diet including powder from the genetically modified tomatoes.

In the first two groups, there were no differences. The third group, however, had a significantly extended lifespan – an average of 182 days, compared to the 142 days for the mice which received the standard diet.

These are encouraging results, but researchers are cautious – the mice had significantly extended lifespans, but the way in which anthocyanins might have caused this is entirely unknown. And the study could not take into account toxicity which might result from the use of GM organisms, or the higher levels of anthocyanins, so there is still a significant amount of research required before human trials could even be considered.