Alcohol consumption and brain health
A recent longitudinal study (over 30 years) showed that, compared with abstinence, moderate alcohol intake (5-7 glasses of wine or 4-6 pints of beer / week) is associated with increased risk of adverse brain outcomes and steeper cognitive decline in lexical fluency. Lexical fluency is the number of words beginning with a specific letter that can be generated in one minute.
Results from this study showed a reduction in hippocampal volume (see picture on the right, source: wikipédia). Hippocampus plays a central role in memory and spatial navigation. It is worth noting that a reduction in hippocampal volume is observed in Alzheimer disease patients.
Also, alcohol consumption induced a reduction in grey matter density. Grey matter contains most of the brain's neuronal cell bodies. It is involved in muscle control, perception such as seeing and hearing, memory, etc.
No protective effect was found for small amounts (less than 5 glasses of wine / week) of alcohol over abstinence.