People who have a drink or two every night from middle age are more likely to experience a steep decline in brain power by their 70s, research suggests.
Even moderate drinkers triple the risk of significant shrinkage in a key part of the brain, scientists discovered.
Consistently drinking between 14 and 21 units a week – the equivalent of six to nine pints of beer or the same number of 175ml glasses of wine – results in brain shrinkage and cognitive decline in old age, scientists found.
Experts warned that the damage from alcohol may start at a lower level than previously thought – and may trigger similar damage to that seen in people with dementia.
Drinking between 14 and 21 units a week used to be considered ‘moderate’ consumption, and until last year was judged safe for men but not recommended for women.
Consistently drinking between 14 and 21 units a week results in brain shrinkage and cognitive decline in old age, scientists found
In January 2016, the Government changed its guidance on drinking and urged both men and women to drink no more than 14 units each week.
The new research, led by the University of Oxford and University College London, suggests the damage from alcohol follows a ‘dose-response’ pattern – meaning the impact gets worse the more you drink, starting from quite a low base.
How was the study carried out?
The team, whose findings were published in the British Medical Journal, tracked 550 people for 30 years, from an average age of 43 until 73.
They repeatedly assessing their alcohol consumption, tested their cognitive ability and scanned their brains.
They found alcohol use was associated with reduced size of the right hippocampus – a part of the brain linked to memory and navigation. Shrinkage of this part of the brain is regarded as an early marker for Alzheimer’s disease.
What did they find?
Even moderate drinkers – those who consumed 14 to 21 units a week – were three times more likely to have significantly reduced hippocampal volume than abstainers, the researchers found.
They also found that very light drinking – classed as drinking between one and six units a week – had no protective effect compared to abstinence.
Moderate drinkers also showed a faster decline in language fluency – tested by how many words beginning with a specific letter can be generated in one minute – dropping 17 per cent more over 30 years than non-drinkers.
People who regularly drink that amount for 30 years are three times as likely to display significant shrinkage in a key part of the brain
The brain images, taken using MRI scanners, showed that those who consumed high amounts of alcohol were more likely to show damage to their white matter – the ‘wiring’ of the brain – though this did not kick in until people were drinking more than 21 units a week.
What the findings support
The authors wrote: ‘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, as 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.
BLAME YOUR PARTNER…
If you are drinking one too many glasses of wine in the evening these days, your other half might be to blame.
A study in January found couples influence each other’s drinking over the years.
They become ‘drinking partners’, probably because they use alcohol to bond and relax together, the scientists found.
But this can cause partners to pick up bad habits and start drinking unhealthy amounts.
And while previous studies have suggested women drink more to keep up with men, the latest study found wives are just as likely to cause their husbands to drink more.
The Dalhousie University in Canada scientists suggest being married to someone who opens a bottle of wine every night makes heavy drinking seem more normal and appealing.
‘Alcohol might represent a modifiable risk factor for cognitive impairment, and primary prevention interventions targeted to later life could be too late.’
Killian Welch, consultant neuropsychiatrist at the Royal Edinburgh Hospital, wrote in a separate editorial piece in the BMJ: ‘The findings strengthen the argument that drinking habits many regard as normal have adverse consequences for health.
‘This is important. 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.’
It’s been known for decades
Andrew Misell of the Alcohol Concern charity, said: ‘We’ve known for decades that heavy drinking can change the shape and structure of the brain, and lead to symptoms very similar to dementia.
‘There is also anecdotal evidence that services are seeing people with alcohol-related brain damage in their 40s and 50s, rather than their 60s and 70s, as they used to.
‘This is just one study, and the researchers admit they cannot say for certain that alcohol is causing the effects that they have observed. But it does suggest that the damage alcohol can cause to the brain may start at lower levels of drinking than we thought.’
Professor Tom Dening of the University of Nottingham added: ‘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.
‘The findings from research on alcohol often generate strong emotional responses, depending on people’s own views, preferences and lifestyles.
‘Perhaps we should all drink a bit less.’