Drinking Shrinks the Hippocampus
For the study published in the British Medical Journal in June, researchers from Oxford University and University College London enrolled 550 men and women with an average age of 43. The researchers then tracked the participants’ alcohol intake and cognitive performance repeatedly over the following 30 years. MRI scans were conducted at the end of the study. The research team measured the volunteers' hippocampus, a part of the brain involved with memory and spatial navigation. It’s one of the first areas to suffer in Alzheimer's. They also looked at white matter microstructure, essential for processing thoughts quickly, and the density of grey matter. The researchers took many factors into account that could influence the results. These included age, sex, education, social class, smoking, physical activity, stroke risk and medical history. The findings were that those drinking just seven to ten medium glasses of wine, pints of beer or shots of liquor per week had three times the amount of hippocampal shrinkage, poorer quality white matter and a more rapid decline in language fluency than nondrinkers over the three decades. And yet these moderate levels of drinking are in line with recommendations for women, and about half the amount considered safe for men. The researchers "call into question the current US guidelines" that one drink a day for women, two for men is perfectly safe. Compared to abstaining altogether, the study authors also found no protective effect from drinking even small amounts of alcohol.Surprising Results
Lead author Anya Topiwala said, "We were surprised that the light to moderate drinkers didn't seem to have that protective effect. These are people who are drinking at levels that many consider social drinkers, so they are not consuming a lot." She believes other studies have reported protective effects "because of limitations in the methods ... for example, not taking full account of characteristics of modern drinkers, such as higher IQ, which would predict better memory test performance and may mask damage done by alcohol." Professor Tom Dening from Nottingham University commented, "This is a most impressive study and I think it will cause us all to reconsider the advice we give to patients about alcohol consumption." In 2016, the safe limits for alcohol in the UK were reduced by a third. That leaves US guidelines for men 75% higher than the UK’s.Should I Give Up Drinking?
Is this study the last word? Not quite. Although it was well-conducted, a number of issues cast doubt on the findings.- It didn't take into account the influence of diet.
- There were too few abstainers to make reliable comparisons
- The participants were drawn from London civil servants and may not be representative of the wider population.
- Alcohol intake was self-reported and possibly underestimated.
- Hippocampal atrophy was only significant for the right side and not the left, for unknown reasons
- The decline in cognition was related to the number of words starting with a certain letter in a particular category the volunteers could think of in 60 seconds. Other tests of cognition showed no significant change
- The research demonstrates an association. It doesn't prove that alcohol causes cognitive decline or atrophy of the hippocampus
