By Liliana Shymanska, Corporate Communications Officer at the British Science Association


For thousands of years, humans have bred crops to our preferred shape, size and flavour. But to what degree can we alter our foods to maximise their health benefits? Plant biologists, Cathie Martin and Eugenio Butelli reveal how plant breeding and bioengineering can be used to improve health and promote healthy ageing at this year’s British Science Festival.

Cathie Martin (John Innes Centre and the University of East Anglia) and Eugenio Butelli (John Innes Centre) kick off their British Science Festival talk pointing to a table filled with a rich variety of different fruits and vegetables including blackcurrants, blueberries and jugs of blood orange juice.

Most of the foods on display appear to be different varieties of purple; all coloured somewhere between the red-blue spectrum. The common pigment that gives all of these foods their colour is a family of antioxidants known as ‘anthocynanins’ (‘blue flower’ in Greek).

Anthocyanins have been linked to a number of health benefits including helping to prevent age-related declines in mental function and potentially, even boosting your metabolism.

Balance is key

Previous animal trials have shown that the anthocynanins in blood oranges (which gives them their dark red hue) might act to help inhibit fat accumulation. 

Cathie recalled an anecdote to the audience; one of her friends explained that she “tried the blood orange juice on my husband…it didn’t work!”. When discussing particular foods such as anthocynanin-rich fruit and vegetables, the speakers emphasised that maintaining a varied, balanced diet is always key.

The big purple tomato

In the next part of their talk, Cathie and Eugenio displayed a lustrous dark purple…tomato. Together with a wider team at John Innes Centre, Cathie and Eugenio have designed a purple tomato with increased levels of anthocyanins.

They explained that domesticated tomatoes already have genes to produce anthocyanins, but they are not ‘turned on’ in fruits. By carefully adding two genes from snapdragons using genetic engineering, the purple tomatoes are a rich source of antioxidants, acting as a great example of biomimicry.

While you may have already spotted purple tomato varieties in shops and supermarkets, these are made by traditional plant breeding methods. These varieties only have anthocyanins present in the skin, so the health benefits they offer are limited.

Two of Cathie and Eugenio’s purple tomatoes on the other hand, equate to the same amount of anthocyanins found in 70g of blackberries.

You may be wondering, if anthocyanins can be found naturally, why go into all the trouble of producing an anthocyanin-rich tomato? Well, tomatoes are often seen as an optimum vehicle for adding vitamins and compounds to a diet. This is because they are not only relatively cheap to buy but are a widely cultivated crop than can be grown almost anywhere across the globe.

Tomatoes vs Parkinson’s

It doesn’t stop there for tomatoes. The John Innes Centre team have also been working to devise a way of turning tomatoes into a inexpensive source of the Parkinson’s drug Levodopa, or L-Dopa.

Genetically modifying the tomatoes in this way to produce otherwise costly medications could potentially help treat more patients in regions where pharmaceutical drugs are hard to get.

So, when can we get our hands on some purple tomatoes?

If you live in the US, potentially within the next year. Purple tomatoes need to receive all the necessary approvals from US regulatory agencies, the United States Department of Agriculture (USDA) and the Food and Drug Administration (FDA),before going out for delivery. But the work is in progress. For the UK, regulation is different, so a time scale is harder to pinpoint.

For now at least, one thing we can all take away is adding naturally anthocyanin-rich fruit and vegetables foods to a varied, balanced diet is a win-win.

The British Science Festival 2021 takes place between 7-11 September, bringing over 100 free events to Chelmsford, hosted by the Anglia Ruskin University. Book your free tickets here: