Researchers hypothesize vitamin B1 (thiamine) deficiency may play a significant role in dementia associated with alcohol use disorder. It is known iron deposits in the brain contribute to neurodegenerative diseases. Those with AUD have elevated levels of both iron in their blood and thiamine deficiency. Thiamine is vital for maintaining the blood-brain barrier. Thiamine deficiency associated with AUD disrupts the integrity of the BBB, allowing for more iron deposits within the brain and leading to oxidative tissue damage.