Resveratrol supplements

Resveratrol is a member of a group of plant compounds called polyphenols. These compounds are thought by some to have antioxidant properties, which may protect the body against the kind of damage linked to increased risk of conditions such as cancer and heart disease. The British Dietetic Association says some phytochemicals such as flavonoids, glucosinolate and phyto-oestrogens: "act as antioxidants, which may reduce damage to cell DNA and cell membranes. Other phytochemicals are thought to influence the activation of carcinogens (cancer causing agents), or increase the level of protective liver enzymes."

Resveratrol is found in the skin of red grapes, but other sources include peanuts and berries.

Because resveratrol is believed to have health benefits, it is not surprising that a number of manufacturers have tried to capitalise on this by selling resveratrol supplements. Most resveratrol capsules contain extracts from the Japanese and Chinese knotweed plant, Polygonum cuspidatum. Other resveratrol supplements are made from red wine or red grape extracts.

Advertisments promoting resveratrol supplements on the Internet promise customers everything from weight loss to a healthier, longer life. The question is: do resveratrol supplements really deliver on those promises?

Possible benefits of resveratrol

Resveratrol has gained much attention for its reported anti-ageing and disease-combating benefits, but this is based on early research, mostly done in test tubes and on animals and more studies are needed.

Some of the conditions that early research suggests resveratrol might help protect against include:

Heart disease. Studies suggest resveratrol may help reduce inflammation, prevents the oxidation of LDL "bad" cholesterol, and makes it more difficult for platelets to stick together and form the clots that can lead to heart attacks.

Cancer. Resveratrol is thought by some researchers to limit the spread of cancer cells and trigger the process of cancer cell death (apoptosis). More research is needed.

Alzheimer's disease. Resveratrol may protect nerve cells from damage and the build-up of plaque that can lead to Alzheimer's.

Diabetes. Studies suggest resveratrol may help prevent insulin resistance, a condition in which the body becomes less sensitive to the effects of the blood sugar-lowering hormone, insulin. Insulin resistance is a precursor to diabetes.

Studies on rodents suggest that resveratrol might even help combat some of the effects of an unhealthy lifestyle and lead to increased longevity. Resveratrol-treated mice fed a high-caloriediet lived longer than similarly fed mice not given resveratrol. Resveratrol protected mice fed a high-calorie diet from obesity-related health problems by mimicking the effects of caloric restriction.

Resveratrol has been linked to prevention of age-related problems such as heart disease and insulin resistance. Some researchers believe that resveratrol activates the SIRT1 gene, a biological mechanism that seems to protect the body against the harmful effects of obesity and the diseases of ageing. More research is needed.