Moderate drinking is associated with decline in brain health, claim researchers

By Sally Robertson, B.Sc.Jun 8 2017

Even drinking moderate amounts of alcohol is associated with an increased risk of brain damage and impaired cognitive function, say researchers.

Heavy drinking has previously been associated with adverse brain outcomes, but few studies have looked at whether moderate drinking also is.

“We knew that drinking heavily for long periods of time was bad for brain health, but we didn’t know at these levels,” says study co-author Anya Topiwala (University of Oxford).

For the study, researchers from the University of Oxford and University College London used data on weekly alcohol intake and cognitive performance tests for 550 healthy men and women, over a 30-year period (1985-2015).

As reported in The BMJ, the average baseline age of the participants was 43 years. Levels of alcohol intake varied, but none of the participants were alcohol dependent. Various aspects of cognitive performance were measured at six points over the 30 years and at the end of the study the researchers performed MRI scans of the participants’ brains.

After adjusting for potential confounders such as age, gender, education, physical activity, smoking status, medical history and social class, the team found that participants who reported higher levels of alcohol consumption were at an increased risk of having hippocampal atrophy, which impairs memory and spatial navigation. Compared with people who did not drink, those who drank more than 30 units of alcohol were at the greatest risk, but even those who consumed a moderate amount of alcohol (14 to 21 units) were at three times the risk.

Higher levels of drinking were also associated with poorer white matter integrity; healthy structure of the white matter is vital for efficient cognitive function. Furthermore, higher drinking levels were associated with a faster decline in lexical fluency. “[That] is where you ask somebody to name as many words as they can within a minute beginning with a certain letter,” explains Topiwala.

The authors say their findings support the recent reduction in recommended UK safe limits as well as calling into question current guidelines in the US.

In an associated editorial, neuropsychiatrist Killian Welch (Royal Edinburgh Hospital) says the findings "strengthen the argument that drinking habits many regard as normal have adverse consequences for health."