Any amount of alcohol is bad for the brain, study suggests
Many people look forward to a glass of wine after a stressful day, or enjoy a post-work pint.
While the odd tipple was generally considered to be harmless, new research by the University of Oxford suggests any amount of alcohol is bad for the brain.
After analysing the brain scans of more than 25,000 adults, the team found that any alcohol consumption was linked to a decline in brain matter, with its effect exceeding that of smoking or being overweight.
While further research is required, a decline in brain matter may affect the vital organ's ability to function.
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The scientists have concluded "no safe dose of alcohol for the brain was found", with even a "moderate consumption" linked to "more widespread adverse effects than previously recognised".
The preliminary results are published on the pre-print server medRxiv and have not yet appeared in a peer-reviewed journal.
"There's no threshold drinking for harm – any alcohol is worse [than not drinking at all]," said lead author Dr Anya Topiwala.
"Pretty much the whole brain seems to be affected, not just specific areas, as previously thought."
The health effects of alcohol have long been debated.
The NHS recommends both men and women do not regularly consume more than 14 units of alcohol a week, with one unit equating to around half a pint of normal-strength beer, a 125ml glass of 12% wine or a single shot of spirits.
Read more: 'High-risk' drinking increased during first lockdown
Those who do drink 14 units of alcohol a week are advised to space these out, with several alcohol-free days.
Having one-too-many may result in injuries, violent behaviour and the spread of sexually-transmitted infections. Over time, an excessive alcohol intake has been linked to heart disease, strokes and several cancers.
On the other hand, research has repeatedly linked a moderate alcohol intake to lower levels of "bad" cholesterol and blood clots that block the arteries, which may otherwise lead to heart attacks and strokes.
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To better understand how alcohol affects the brain specifically, the Oxford scientists analysed participants of the UK Biobank study, who had an average age of 54.
The participants' alcohol consumption was assessed via a questionnaire. They then underwent MRI brain scans and "cognitive testing".
Results reveal any level of alcohol consumption was associated with a decline in brain grey matter, which controls all the vital organ's functions.
Alcohol was found to be behind up to 0.8% of the change to the grey matter volume. While it may sound a relatively small figure, this is around four times the effect of smoking or a high body mass index (BMI), according to Dr Topiwala.
Read more: One small glass of alcohol a day raises risk of irregular heartbeat
Drinking was also linked to a reduction in "white matter microstructure", which connects different parts of the brain.
The risk was greatest among the drinkers who had raised blood pressure or a high BMI.
Perhaps unsurprisingly, binge drinking had "additional negative effects on top of the absolute volume" of alcohol consumed.
No difference was found between different types of alcohol, despite wine often being hailed as healthy in moderation.
The scientists believe these apparent health benefits may be explained by the sort of people who drink wine.
"If you look at who is moderately drinking, at least in this country, they are better educated, wealthier people that would do much better on a memory test", said Dr Topiwala.
Overall, the team concluded: "No safe dose of alcohol for the brain was found.
"Moderate consumption is associated with more widespread adverse effects on the brain than previously recognised.
"Current 'low risk' drinking guidelines should be revisited to take account of brain effects."
Lucy Holmes from Alcohol Change UK told Yahoo UK: "Alcohol affects all areas of our bodies, from our skin to our heart to our liver to our brain.
"We already knew heavy drinking has a negative impact on the brain, increasing the risk of dementia [and] stroke, and putting us at risk of alcohol-related brain damage.
"What the public needs and wants is clear, reliable guidance to help us choose how much to drink. The low-risk drinking guidelines are there to help – drinking 14 units a week or less is the best way to stay healthy.
"It's important all drinkers have ready access to this guidance when making choices, including on all alcohol packaging."
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