Purple GM tomatoes? Yeah right

I don't exactly make a secret of my opposition to genetically modified foods, so you wouldn't expect me to be impressed by a piece in today's Guardian trumpeting the wonders of a new GM tomato. But actually I was bloody boiling mad after reading the piece. Not because of the GM tomato itself (nobody is trying to force me to eat it) but because the report is a gross and cynical misrepresentation.

"Tomatoes that have been genetically modified to be rich in antioxidants can give protection against cancer, a team of British scientists has found.

Researchers at the John Innes Centre in Norwich created the crop of purple tomatoes by altering them with genes from snapdragon flowers. In tests, mice that were prone to cancer lived almost a third longer if their diet was supplemented by the modified tomatoes.

The findings, which appear in the journal Nature Biotechnology, pave the way for a new generation of "functional foods" that could potentially offer protection against serious diseases.

Derek Burke, former chair of the UK's regulatory committee on GM, said: "This is a truly positive outcome from genetic modification of plants, and a real help to people wanting to improve their diets." "

It's not that the health claims being made here are untrue. Purple fruits and veg are rich in anthocyanin which is already known to have health benefits and may indeed be useful in fighting cancer, which is why most of my pea-breeding projects focus on producing purple peas. These findings are not new, and I don't dispute them.

The suggestion, however, that this is a wonderful new breakthrough only made possible by genetic engineering is complete and utter bollocks.

To the general public who are used to seeing only red tomatoes in the shops, the idea of a purple tomato may seem quite novel (and for sure they have nice pictures of it and it looks very pretty). But for those who browse heirloom seedlists they're not exactly new. I seem to recall seeing a packet of exquisitely purple toms from the SSE floating around in Patrick's box at the Oxford seed swap. Admittedly I haven't seen any with the intensity of purple shown in the GM ones, but the point is that if tomatoes can naturally produce anthocyanin then they can be selectively bred to produce larger amounts of it. No gene splicing from the flower borders required.

So I really have to ask ... what the hell is the point? Normal red tomatoes are naturally rich in lycopene which is another nutritional wonder-pigment. Orange tomatoes are generally rich in beta-carotene which makes Vitamin A. You are already doing plenty of good to your health if you eat red and orange tomatoes.

More or less any fruit or veg with purple colouring is already packed with anthocyanin. Blackberries, blueberries, blackcurrants, jostaberries. Red cabbage. Aubergines (egg plants). Cherries. Purple sprouting broccoli. Red wine.

Which begs the question, why go to all that trouble to splice anthocyanin into tomatoes? It adds nothing to western diets. It uses an expensive patented technology which the consumer will ultimately have to pay for. And it's being presented to the public in a cynical haze of hype and spin.

Whatever the motivations of the team who developed this tomato, who may have had good reasons, I am disgusted with the way the report is being carried in the media. It looks to all intents and purposes like a propaganda campaign on behalf of the industry. GM technology getting the credit for something that nature is producing perfectly well by herself. A cynical attempt to sell the idea of GM foods to the general public on the basis that most people don't know much about the science of plant pigments and won't realise it's a marketing wheeze.

I find it quite scary that the former chair of the UK's regulatory committee on GM is trumpeting this tomato as a nutritional advance. I wonder what planet these people are on and whether they read anything other than Monsanto brochures.

Want to get the benefit of this amazing cancer-eradicating anthocyanin stuff? Then take my advice. Eat more blueberries.

EDIT: Here we go, it has already been done. Many thanks to Graham for pointing me to this excellent discussion about a purple-blue tomato bred by Oregon State University using conventional methods. It has an exceptionally high anthocyanin content (as well as the usual carotenoids) and is derived from crosses with wild tomato species. All in the public domain and being freely shared among breeders.