Resveratrol is an antioxidant compound produced by plants. Resveratrol provides a natural defence against disease and attack by bacteria, fungi and other threats for plants - and apparently, humans. In humans, resveratrol is believed by some to activate genes that help to promote longevity. Scientific studies have shown that resveratrol doubles the lifespan of yeast and also increases longevity in worms and fruit flies. A 2006 study in the journal Current Biology found that it extended the lifespan of fish by 56 per cent.

Resveratrol may also inhibit cancer. As a supplement, resveratrol has been shown in studies to diminish cancer development via anti-inflammatory and antioxidant action, and by regulating normal cell growth. In one 2000 study in Cancer Letters, the treatment of human colon cancer cells with resveratrol caused a 70 per cent inhibition in growth. Other research found it to be effective in reducing growth of breast cancer cells. Possible weight-loss aid —a 2006 study in Current Medicinal Chemisoy found resveratrol inhibits the action of an enzyme needed to convert sugars into fat, and reduces insulin levels, so reducing hunger and blood sugar imbalances.

Resveratrol has been found to prevent changes in LDL cholesterol, which leads to hardening of the arteries and coronary heart disease. It has also been shown to reduce platelet clumping, so thinning the blood, which helps protect against heart disease.

Resveratrol can be found in abundance in red grapes, red wine and red grape juice. The skin and seeds of the red grapes used in the wine-making process contain resveratrol, which appears to have a beneficial effect on both cardiovascular health and, possibly, lifespan.The better-quality reds contain more resveratrol. Researchers have also found, for example, that a good bottle of merfot or pinot noir can provide around 20mg of resveratrol, while cheap wines may only contain as little as 2mg.

The antioxidant is also present in the skins of peanuts, blue tinted berries such as mulberries, blueberries and cranberries, and dark chocolate. Resveratrol supplements are often made from Japanese knotweed.

The optimal intake of resveratrol is not yet known, but taking 25-5omg resveratrol a day is thought to be a good start.