It sounds like the elixir of life: a wonder drug that promotes youth, slimness and sexual allure at the same time as protecting against heart disease and cancer.

Impossible? Not to researchers investigating a substance called resveratrol, which they believe could be the holy grail of the pharmaceutical industry: a single drug to counter "lifestyle" illnesses...

Tests are showing that resveratrol can help body cells to repair themselves and — a potentially huge selling point — speed up fat-burning within the cells. If it really does work, it is a drug company’s dream: a pill to help you stay young and slim.