Per a new study published in The BMJ , having as few as eight drinks a week may be associated with cognitive decline and even brain shrinkage. While previous research has suggested that light to moderate drinking could protect the brain , this study found light drinking provided no benefit.
Why does this research contradict previous studies? These findings came from a British study, which enrolled 550 government employees in 1985 and followed them for 30 years. The participants provided information on their age, sex, education, health, and social activities. Every five years, they took cognitive tests examining language and memory. At the final study visit, the researchers scanned the brains of the participants to look for differences in brain volume and connectivity.
What they found was that higher alcohol consumption was associated with a greater decline in some language skills, even in those only having four to eight drinks per week. The researchers also discovered that those who drank more than eight alcoholic beverages per week had a greater loss of volume in the hippocampus, which is the brain region associated with memory and Alzheimer's disease. Based on these findings, the researchers argue that the current U.S. guidelines for safe drinking—one drink per day for women and two for men—may be too high.
Is even light drinking bad for your brain health? There are a number of factors you should consider before you decide to skip that glass of wine. First, the study looked at 550 educated government workers in the UK, 85 percent of whom were men. This was a small, uniform group, and these results may not apply to the population at large. Also, we cannot conclude that alcohol caused the decrease in brain volume, only that in this study it was associated with it. Observational studies like this one are rife with confounding factors that make it difficult to determine "cause and effect." We don't know if some other factor might be the real cause for the decline in cognition.
This study also runs counter to others that suggest light to moderate alcohol consumption may prevent cognitive decline and decrease the risk for Alzheimer's disease later in life [2-4]. However, these studies are also observational, and it is not clear that there is an optimal amount of alcohol consumption to reduce Alzheimer's risk.
Research does indicate that alcohol consumption is potentially more harmful in the elderly . Since older people are less able to metabolize alcohol, it can have a greater effect and may exacerbate underlying cognitive problems. Current guidelines recommend that healthy adults over the age of 65 who are not taking other medications should have no more than seven drinks per week, or one per day, regardless of gender [6-8]. And, elderly people on multiple medications should probably not drink at all because of the potential negative interactions.
At the end of the day, there is no conclusive evidence suggesting that light to moderate drinking will promote or prevent Alzheimer's disease . Though, evidence of potential harm is higher for elderly people. To find out more about alcohol consumption and your risk for Alzheimer's disease, see our Cognitive Vitality report.
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