People who consume up to 14 units of alcohol a week have less chance of developing cataracts, especially if they drink red wine, a new British study has found.
Antioxidants found in wine could help explain why moderate drinkers are at up to 23% less risk of having to have cataract surgery than people who shun alcohol, the researchers believe.
Cataracts – cloudy patches that form in the lens of the eye – are a major cause of impaired eyesight and blindness, mainly in older people. Removing them in a short procedure is the commonest surgery carried out by the NHS, which performs about 450,000 such operations a year in England.
Academics from Moorfields eye hospital in London and University College London’s institute of ophthalmology studied the medical and lifestyle history of 492,549 participants in either the UK Biobank or Epic-Norfolk studies of people’s health over many decades.
They found that people who drank within the 14 units a week maximum recommended by the government – equating to about six and a half glasses – were less likely to have cataract surgery. Risk was lower among wine drinkers than those who consumed beer or spirits. In the Epic-Norfolk study those who drank wine at least five times a week were 23% less likely to have cataract removal than non-drinkers while those in the UK Biobank study were 14% less likely.
“Cataract development may be due to gradual damage from oxidative stress during ageing. The fact that our findings were particularly evident in wine drinkers may suggest a protective role of polyphenol antioxidants, which are especially abundant in red wine,” said Dr Sharon Chua, the first author of the findings, which have been published in the journal Ophthalmology.
Dr Anthony Khawaja, who led the research, added: “We observed a dose-response with our findings – in other words, there was evidence for reducing chance of requiring future cataract surgery with progressively higher alcohol intake, but only up to moderate levels within current guidelines.”
The authors stressed, though, that while there appeared to be a close association between moderate drinking and cataracts, they had not found a definite causal link.
The NHS has identified drinking as one of the risk factors for cataracts, alongside smoking, diabetes and family history.
Dr Sadie Boniface, the head of research at the Institute of Alcohol Studies thinktank, cast doubt on the findings. Longitudinal studies such as UK Biobank could give a skewed picture of the nation’s health because many volunteers were often in good health, she said.
“Comparing the health of moderate drinkers with that of non-drinkers also carries problems. Non-drinkers are a diverse group, including people who have stopped drinking because of health problems. This means moderate drinking can artificially look like it carries health benefits, because the moderate drinkers are compared to people on average in poor health,” said Boniface.
“The bigger effect seen among wine drinkers may be because of other characteristics of this group to do with their cataract risk which weren’t accounted for. If the amount of alcohol or number of units somebody drinks was having a direct effect, you’d expect this to be similar regardless of drink type.”
