Jeremy Laurance: 'Revealed: the real reason we should eat up our greens'

Medical Life

The Mediterranean diet – sun-kissed, olive-oil drenched – has reigned as the queen of diets, the one true path to health, for at least 20 years. Yet no one really understands why it works. Most medical authorities have said the antioxidants in fruit and vegetables account for its protective effects. (Also, if you eat enough broccoli, you don't have room for a double Big Mac and fries.)

But research on antioxidants – vitamins, by another name – has proved disappointing. Huge studies of populations that swallow vitamin supplements by the bucket have yielded negative findings. Vitamins, at least in supplement form, appear to have no beneficial effect.

Is it possible that scientists are looking in the wrong place? Professor Peter Elwood of Cardiff University raised this possibility last week. He was the first researcher to establish the role of aspirin in protecting against heart disease, in 1974, and millions of people worldwide now take a daily aspirin.

Over the past 35 years, Elwood has published more than 60 papers on aspirin. The latest appears in the current Lancet, and in it he discusses the drug's protective effect against cancer and its presence in fruit and vegetables. "I think this is a very exciting area that should be researched in considerable depth. The whole field of antioxidant research has proved very unproductive... It leads us to wonder if the beneficial effects of fruit and vegetables are because of the salicylates they contain," he said.

A further twist is that plants produce salicylates in response to injury or assault by pests, so the perfect specimens you find in supermarkets grown on farms that cosset them have lower levels than the bruised, misshapen ones grown organically.

So convinced are some researchers that salicylates are responsible for the cancer-protective effects of fruit and veg that they have dubbed them vitamin S. Given that most people don't manage their five a day, a simple aspirin costing pennies may do a lot more good than a fistful of multivitamins.

There is a problem, however. Aspirin has side effects, especially as a cause of internal bleeding. Elwood wants more research into the risks and benefits of aspirin, and the development of a safer version. Why has this not been done? Because there is no money in a drug that went off patent more than a century ago. Yet vitamin S might save more lives than all other vitamin supplements put together.