Thiamine Deficiency in Alcoholics (Easily) Explained
Heavy drinking has many health risks you’re probably tired of hearing about. But there’s one that doesn’t get nearly enough attention: thiamine deficiency in alcoholics.
I’ll give a brief breakdown of what thiamine does, why alcohol makes it hard for us to get enough of this critical vitamin, and what happens if we let it go for too long.
(Hint: very bad things)
What does thiamine do?
Brain cells need thiamine (a.k.a. vitamin B1) to maintain the adequate function of enzymes essential to the cells’ metabolism and functioning. In addition, thiamine helps maintain cell membrane structure, the excitability of the nerve cells, and the conduction of nerve impulses.
We get thiamine through diet. When we eat food sources that contain thiamine, the nutrient is absorbed through the intestinal tract and delivered to the brain.Â

Three important enzymes that need thiamine:
- alpha-ketoglutarate dehydrogenase
- pyruvate dehydrogenase complexes
- Transketolase
Impossible pronunciation aside, these enzymes are very important!
The first two play a crucial role in brain cells’ energy production. If either enzyme is decreased for too long, it can lead to cell death.
The third enzyme, transketolase, plays a critical role in the maintenance and synthesis of myelin.
Myelin is the protective sheath surrounding our nerves, allowing electrical impulses to travel quickly along our nerve cells. When myelin gets damaged, those impulses slow down, and our nervous system cannot function properly.
Alcohol & Thiamine Deficiency
Any reduction in thiamine levels has severe consequences for brain metabolism, leading to brain lesions and cognitive impairments. The numbers give us a dire warning. Up to 80% of people with chronic alcoholism develop thiamin deficiency.
But why do heavy drinkers have a high risk for thiamine deficiency?
1. Poor Diet
Alcoholics and heavy drinkers do not typically eat a well-rounded diet.
They often skip meals and, when they do eat, consume high carbohydrate diets that are low in vitamins like thiamine.
Additionally, high carbohydrate diets further deplete thiamine levels in the body because the enzymes required to break down carbs require thiamine.Â

2. Malabsorption and Poor Gut Health
Alcohol damages the lining of the intestine, which is bad because we need our intestines to function correctly to get adequate amounts of thiamine into our body.
We get thiamine via diet, and the cells absorb it via the intestinal lining.
From there, thiamine is transported out of those cells into the bloodstream and the body’s tissues and cells.Â
If the intestinal lining is damaged, our ability to absorb nutrients properly, including thiamine, is also impaired.Â
When combined with nutritional deficiencies from a poor diet, you risk severe complications.
3. Damage to Thiamine-Metabolizing Enzymes in the Brain
I know that’s a mouthful, but let me explain in plain English.
For thiamine to work its magic in the brain, it must be converted into an “active form” by an enzyme called thiamine pyrophosphokinase (say that one three times fast).
Guess what alcohol does?
That’s right! It decreases thiamine pyrophosphokinase activity.
Alcohol also increases the activity of enzymes that break down activated thiamine in the brain.
The result is a reduction in thiamine-dependent enzymes, negatively impacting brain metabolism.
What does thiamine deficiency do?
In its most extreme form, alcohol-induced thiamine deficiency leads to Wernicke-Korsakoff syndrome (WKS), also known as “wet brain.”
Wernicke-Korsakoff syndrome (WKS) is a neurological disorder caused by a deficiency of thiamine (vitamin B1). It typically results in two distinct problems: Wernicke’s encephalopathy and Korsakoff’s psychosis.
Wernicke’s encephalopathy is a more serious condition that can cause confusion, disorientation, and problems with muscle coordination.
Korsakoff’s psychosis is a disorder that affects memory. People with this disorder often fill in gaps in their memory with made-up stories. This usually happens later, after the person has had the condition for some time.
If left unchecked for too long, thiamine deficiency creates irreversible and often fatal damage to the brain.
For a comprehensive explainer of WKS and thiamine deficiency, check out this video:
Symptoms of Thiamine Deficiency in Alcoholics
Early detection is vital when dealing with thiamine deficiency in alcoholics.
It is possible with early, intense medical intervention followed by sobriety to reverse the damage and recover.
But, as I mentioned in the previous section, the longer you leave it and continue drinking, the greater the risk to your health. There is a point of no return, so we have to take thiamine deficiency seriously.
If you are a heavy drinker and experience any of the following symptoms, book an appointment with a doctor immediately.
No excuses. Please do not put it off.
- Loss of appetite
- Weight loss
- Chronic fatigue
- Nausea
- Weakness in legs
- Heart palpitations
- Muscle weakness
- Blurry vision
- Tingling sensation in arms and hands (pins and needles)
- Poor concentration levels
- Water retention (edema)
- Irritability and low mood
Sources: https://www.rehabguide.co.uk/thiamine/ and https://adf.org.au/insights/alcohol-related-thiamine-deficiency/
How do they treat thiamine deficiency in alcoholics?
The treatment for alcohol-induced thiamine deficiency is two-fold: medical detox of alcohol followed by addiction treatment and vitamin B1 injections.
Alcoholics who catch the disease early enough will use a combination of stopping alcohol, eating a diet rich in B1 vitamin sources, and taking vitamin B1 supplements.
What are some natural sources of vitamin B1?
If you are a heavy drinker or someone who used to be, it is essential to get tested for vitamin deficiencies and use diet and supplements to help reverse the damage from your drinking days.
Natural food courses for vitamin B1 include:
- whole-grain products such as cereals, rice, pasta, and flour
- wheat germ
- beef and pork
- trout and bluefin tuna
- eggs
- legumes and peas
- nuts and seeds
Bottom Line on Thiamin Deficiency in Alcoholics
Of all the health risks associated with heavy drinking, thiamine deficiency is among the most serious. Do not wait until symptoms start presenting to get checked for thiamin deficiency.
Early symptoms of thiamine deficiency like chronic fatigue, decreased appetite, and constipation are not often specific enough to raise alarms.
By the time more severe symptoms present, the damage has progressed, often beyond what is reversible.
If you fit the clinical definition of a heavy drinker, it’s time to get checked for thiamine deficiency and take the necessary steps to prevent WKS.
