The popular wisdom that a couple of glasses of wine a night can actually help your heart could be misguided, according to new research showing that even the smallest amount of alcohol can have an impact on health.
A study published in the British Medical Journal has concluded that drinking less alcohol could improve the cardiovascular health of even low and moderate drinkers.
While previous research has suggested that small amounts of alcohol can be beneficial, scientists believe the results could have been skewed by the fact that people who drink less are more likely to lead healthier lifestyles overall, with balanced diets and exercise.
Research on the drinking habits of more than 250,000 people in 56 separate studies was examined by scientists at the London School of Hygiene and Tropical Medicine, University College London and University of Pennsylvania in the US.
It concluded that people who drink less have a 10 per cent lower risk of coronary heart disease and just 12 units a week – less than a pint of beer or one large glass of wine a day – can have a negative effect on health.
People carrying the ADH1B genetic variant associated with non-drinking and lower consumption had a “more favourable cardiovascular profile” than those without, it found.
The research showed that people with a genetic predisposition to drink less had a reduced risk of coronary heart disease and stroke, and lower levels of risk factors for cardiovascular disease.
They also had healthier blood pressure and lower body mass indexes.
The study's senior author, Juan Casas, a professor of epidemiology at the London School of Hygiene and Tropical Medicine, said: “It appears that even if you're a light drinker, reducing your alcohol consumption could be beneficial for your heart.”
Dr Shannon Amoils, a senior research advisor at the British Heart Foundation, which funded the study alongside the Medical Research Council, admitted studies into alcohol consumption were “fraught with difficulty” because they rely on people being honest about the amount they drink.
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She added: “Here the researchers used a clever study design to get round this problem by including people who had a gene that predisposes them to drink less.
“The results reinforce the view that small to moderate amounts of alcohol may not be healthy for the heart, although the study would need to be repeated in a larger group of people for definitive results.”
Tim Spector, a professor of genetic epidemiology at King's College London, said the gene markers used were often a better way of assessing behaviour than “unreliable questionnaires”.
Authors of the study hope it will influence government policy on alcohol consumption.
The current national guidelines state that women should not drink more than two to three units a day, and men no more than three or four.
A standard glass of wine is around two units, while a one pint of strong beer or cider can amount to three.
Additional reporting by PA