August 30, 2018

Alcohol and thiamine


Thiamine, also known as vitamin B1, has several essential functions within our bodies and can be deficient in people who consume a lot of alcohol. 

It’s an important nutrient which processes proteins, fats, and carbohydrates to be used as energy by the brain, nerves and heart.1

Thiamine is naturally present in some foods, including:

  • 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.2

It’s also added to food products like bread3 and is available as a dietary supplement.

While fruit, vegetables, and dairy products are not very high in thiamine, they can become a substantial source of thiamine when eaten in large amounts.2

Thiamine deficiency

Thiamine deficiency is common in drinkers who consume excessive amounts of alcohol. This is due to:

  • poor nutrition and the diet not containing enough essential vitamins
  • inflammation of the stomach lining due to excessive alcohol consumption, which reduces the body’s ability to absorb vitamins.4

Thiamine deficiency can cause:

  • loss of appetite
  • constipation
  • fatigue and muscle weakness.

What happens if I’m thiamine deficient?

Excessive alcohol use causes thiamine deficiency in a few different ways, and if allowed to become severe, it can lead to a potentially life-threatening condition.

If a lack of thiamine persists, a condition called beriberi may develop over weeks or months.5 There are two types of beriberi - wet beriberi and dry beriberi. 

Wet beriberi affects the heart and circulatory system and in extreme cases can cause heart failure. 

Dry beriberi damages the nerves and can lead to decreased muscle strength and eventually, muscle paralysis. If untreated, beriberi can be life-threatening.5

In extreme cases, beriberi is associated with Wernicke-Korsakoff syndrome. Wernicke encephalopathy and Korsakoff syndrome are two forms of brain damage caused by thiamine deficiency. 

Both are conditions often caused by excessive alcohol use.4

Wernicke–Korsakoff’s syndrome

Wernicke’s encephalopathy is a form of serious brain injury resulting from a lack of thiamine that most commonly occurs in alcohol-dependent people. 

It’s not a withdrawal complication, but is often identified in people undergoing alcohol withdrawal. It can co-exist with and should be distinguished from acute alcohol withdrawal, loss of brain function due to liver disease, and other causes of confusion.6

Wernicke’s encephalopathy is usually reversible, but if untreated or inadequately treated can lead to Korsakoff’s syndrome, a chronic and disabling condition characterised by severe short-term memory loss and impaired ability to acquire new information. 

It’s important to remember that Korsakoff’s syndrome is not dementia or delirium.6

Symptoms of Wernicke-Korsakoff’s syndrome include:

  • mental confusion
  • paralysis of the nerves that move the eyes
  • an impaired ability to coordinate movements particularly of the lower extremities.

If you’re concerned about vitamin depletion as a result of drinking alcohol, talk to your health professional.

  1. Whittington Health. About Thiamine (B1) and Thiamine Deficiency. London: North London Obesity Surgery Service Available from:
  2. Medline Plus. Thiamin. Bethesda: U.S. National Library of Medicine; 2019 Available from:
  3. Food Standards Australia & New Zealand. Thiamin levels in Australian breads: Results from the 2010 and 2012 national bread surveys Food Standards Australia New Zealand; 2016 Available from:
  4. Dementia Australia. Alcohol related dementia and Wernicke-Korsakoff syndrome: Dementia Australia; 2016 Available from:
  5. Upfal J. Australian drug guide : the plain language guide to drugs and medicines of all kinds. Melbourne, Vic.: Black Inc.; 2016.
  6. Drug and Alcohol Services South Australia (DASSA). Management of patients at risk of alcohol withdrawal in acute hospitals. Government of South Australia; 2016.

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