A glass of wine a day was linked with changes in the structure of the brain.
One glass of wine a day is enough to damage the brain and could raise the risk of Alzheimer’s disease, study by Oxford University suggests.
The research found that those who are moderate drinkers – in line with recommended weekly limits – are three times more likely to suffer atrophy to the brain, with a steeper rate of cognitive decline.
The 30-year study tracked 550 civil servants, with brain imaging used to explore links between drinking and brain health.
Those drinking between 14 and 21 units of alcohol a week – six to nine medium glasses of wine – were three times more likely than teetotallers to suffer hippocampal atrophy.
A picture of a healthy brain of a non drinker.
The greatest risks were among the heaviest drinkers. Those consuming more than 30 units of alcohol saw an almost six-fold rise in their risk.
Researchers used data on weekly alcohol intake and cognitive performance measured repeatedly between 1985 and 2015 for 550 healthy men and women.
Participants had an average age of 43 at the start of the study and none were alcohol dependent. Brain function tests were carried out at regular intervals and at the end of the study participants underwent an MRI brain scan.
Last year, the Government changed its guidance on drinking and urged both men and women to drink no more than 14 units each week – the equivalent of six pints of average strength beer.
Previously it was recommended that men should consume no more than 21 units and women should not drink more than 14 units each week.
Researchers said their findings have “important” potential public health implications.
Doctor Anya Topiwala, clinical lecturer in old age psychiatry at Oxford University, said: “Our findings support the recent reduction in UK safe limits and call into question the current US guidelines, which suggest that up to 24.5 units a week is safe for men.
“We found increased odds of hippocampal atrophy at just 14 to 21 units a week, and we found no support for a protective effect of light consumption on brain structure.
“Alcohol might represent a modifiable risk factor for cognitive impairment, and primary prevention interventions targeted to later life could be too late.”
Doctor Killian Welch, consultant neuropsychiatrist at the Royal Edinburgh Hospital, said the findings “strengthen the argument that drinking habits many regard as normal have adverse consequences for health.”
“We all use rationalisations to justify persistence with behaviours not in our long-term interest.
“With publication of this paper, justification of ‘moderate’ drinking on the grounds of brain health becomes a little harder.”
Prof Tom Dening, Professor of Dementia Research at the University of Nottingham, said: “This is a most impressive study and I think it will cause us all to reconsider the advice that we give to patients about alcohol consumption… perhaps we should all drink a bit less.”
But he said the research relied on participants keeping accurate records of their drinking, when many are prone to under-estimate their intake.
Dr Elizabeth Coulthard, Consultant Senior Lecturer in Dementia Neurology at the University of Bristol, said: “An observational study cannot truly prove that alcohol causes dementia, but the findings are in keeping with my clinical experience.
“The toll of high alcohol consumption on cognitive health, often evident to those of us who run memory clinics, is not widely acknowledged publicly. Hopefully this research will contribute to a greater understanding of true safe limits for alcohol consumption.”