Moderate alcohol consumption has adverse effect on brain function

By Dr. Ananya Mandal, MDJun 6 2017

A new study reported this week suggests that drinking moderate amounts of alcohol may also change the brain structure significantly and lead to worsening of functions.

The study in question spanned over three decades (between 1985 and 2015) and looked at the brains and brain functions of 550 middle-aged persons. The average age of the participants was 43 and the study included both men and women. These were heavy drinkers, moderate drinkers or teetotallers. The participants underwent regular brain function tests and at the end of the study underwent an MRI scan of their brains.

Results of the study showed that those who drank more alcohol had a greater risk of hippocampal atrophy. The hippocampus is an area in the brain that is associated with memory. The researchers noted that those who drank more developed a condition where the hippocampus slowly shrunk in size. This led to damage in memory functions and spatial navigation functions.

Scientists further quantified that, persons drinking more than 30 units a week on average, were at the greatest risk of hippocampal atrophy and brain damage. However even moderate drinkers were not spared they said. Moderate drinking was classified between 14 and 21 units a week. Even these individuals were more likely to develop hippocampal atrophy than teetotallers. There was a particular feature called poor “white matter integrity” that was seen even among moderate drinkers. This led to poorer cognitive functioning said the researchers.

The results had to be adjusted to a whole lot of variables which could affect the memory and other brain functions with or without the influence of alcohol. These factors included education, social standing, gender, age, social behaviours, risk of stroke, diabetes and other medical conditions, smoking etc.

The team of researchers from University of Oxford and University College London went on to say that drinking limit guidelines in Britain at present were in agreement with this study results. However limits recommended in the United States were much higher at 24.5 units of alcohol a week recommended to be safe for men. This study however earmarks levels at 14 to 21 units a week as dangerous too. A unit means 10 milliliters (ml) of pure alcohol which could be half of a large beer. There are nine units in a bottle of wine and a single unit in a 25 ml spirit shot.

The results from this study were published in the BMJ - British Medical Journal. This study downplays the health benefits of regular consumption of alcohol. What is perceived to be normal in most individuals may actually be harmful say researchers.

Researchers however said that these studies are not air tight and their findings may not be absolute. However, this being a long term study, it does carry weight and a warning for the public at large. It could be made more relevant and appropriate for large populations if it were conducted in a large number of persons over a long period of time suggest researchers.