At its core, wet brain is a form of brain damage from severe, long-term alcohol abuse. In scientific terms, wet brain is called Wernicke-Korsakoff syndrome, and the condition is directly related to a deficiency of B1 vitamins or thiamine.
Thiamine is vital to many important bodily processes and systems, but it does not occur naturally within the body like other essential nutrients such as iron. For someone to obtain the recommended daily amount of thiamine, they need to consume it either in food or drink. A reduction in essential B1 vitamins is a natural consequence of a poor diet. A poor diet is a common occurrence in those who abuse alcohol long term.
Although heavy, compulsive drinking prevents people from eating healthy food, alcohol also prevents the body from absorbing thiamine and leeches it from the body. The liver is where thiamine is stored. The liver naturally releases thiamine into the body in an active state. Alcohol interferes with this process. The thiamine stored in the liver is rendered inactive and unusable once a person begins to drink heavily and often.
Thiamine is incredibly important for many bodily systems and tissues to function properly. There are numerous enzymes in the brain that need thiamine to function, including many important neurotransmitters. When the brain is unable to get the correct amount of thiamine over a long period of time, it experiences damage. Vitamin B1 deficiencies are rare occurrences in the US, except in people who regularly abuse alcohol or who have a serious autoimmune disorder such as HIV or AIDS.