Auckland: Researchers in New Zealand say that a daily glass of wine, long recommended as beneficial for heart disease, may have the opposite effect.

They say previous research failed to allow for the fact that people who stop drinking because of heart problems may be included in studies and misclassified as never having consumed alcohol. This would result in the misleading impression that small amounts of alcohol consumed regularly protect against heart disease.

The latest analysis, reported in the medical magazine, The Lancet, contrasts with the prevalent opinion in France, where a daily glass of wine is seen as part of a healthy way of life.

One influential study recently suggested having up to three drinks a day, each containing about ten grams of alcohol, could reduce heart attack risk by a quarter.

But Dr Rod Jackson, who led the latest study, says any benefit from light to moderate drinking is probably small and unlikely to outweigh the harm caused by alcohol. He says the first studies showing the protective effect of alcohol were published in the 1970s and 1980s. These early observations were confirmed by a meta-analysis – a pooling together of findings from different studies, which indicated a 20 per cent to 25 per cent cut in heart disease risk linked to light drinking. But sDr Jackson of the University of Auckland claims these studies failed to avoid confounding errors that gave misleading results.

For instance, a study published this year involving 200,000 U.S. adults found 27 of 30 cardiovascular risk factors were significantly more common in non- drinkers than light to moderate drinkers.

Such risk factors, already present in study participants, could sway the results, it is suggested.

If anything, the evidence of heart protection is more convincing for heavy drinkers, say the Auckland experts.

Post-mortem studies show alcoholics have relatively ‘clean’ arteries, but the risks of alcohol abuse for these people greatly outweighed any benefit from drinking.

Alcohol abuse harms almost every organ in the body, causing problems such as cirrhosis of the liver, pancreatitis, stomach bleeding, high blood pressure, stroke, nerve damage, osteoporosis and dementia.

Dr Jackson said: ‘Any coronary protection from light to moderate drinking will be very small and unlikely to outweigh the harms.’