Chronic alcohol consumption causes brain shrinkage, by reducing both grey and white matter volume. Even low-to-moderate consumption of alcohol is associated with brain atrophy. (http://pubmed.ncbi.nih.gov). Direct toxicity is the cause as Ethanol damages brain cells and interferes with the creation of new neurons, especially in the hippocampus which handles memory. In Alcohol related brain damage (ARBD) memory and thinking abilities worsen over time. ( http://www.alzheimers.or.uk). Alcohol related dementia is a type of dementia due to alcoholism. Any level of alcohol consumption increases risk of dementia ( University of Oxford, ox.ac.uk)
There is no safe limit. In my clinical experience, I have observed that CT scan or MRI of the brain of an alcoholic person show features of cerebral atrophy. The CT or MRI of 40 year old alcoholic person resembles the brain of a 70 year old with radiological features of cerebral atrophy.
