November 3, 2021

Alcohol and thiamine


Thiamine, also known as vitamin B1, is an essential nutrient used by the body to convert food into energy.  

Thiamine takes the fats, proteins and carbohydrates we consume and uses them to fuel functions of the heart, nerves and brain.1

Because the body cannot produce thiamine, it must be consumed through foods like: 

  • 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

Smaller amounts of thiamine are present in fruit, vegetables and dairy products.2

Thiamine is also added to food products like bread and is available as a dietary supplement.3

Thiamine deficiency

Thiamine deficiency, although rare in most developed countries, is common in people who drink excessive amounts of alcohol

Up to 80% of people with an addiction to alcohol develop thiamine deficiency.1

Heavy alcohol use causes inflammation of the stomach lining and digestive tract, which reduces the body’s ability to absorb vitamins. Poor dietary choices and a lack of nutrition also rob the body of essential vitamins.4

Thiamine deficiency can cause:

  • loss of appetite
  • constipation
  • fatigue
  • blurry vision
  • changes in heart rate
  • irritability
  • nausea and vomiting
  • reduced reflexes and tingling sensation in the arms and legs
  • shortness of breath
  • muscle weakness.1,5

Other people at risk of thiamine deficiency include older adults, people who’ve had bariatric (weight loss) surgery, and people with HIV/AIDS or diabetes.1

What happens if I’m thiamine deficient?

The early stages of thiamine deficiency often go undiagnosed as the initial signs – decreased appetite, constipation and fatigue – are non-specific.

If the body continues to experience a lack of thiamine absorption, it can lead to serious health conditions including beriberi and Wernicke-Korsakoff syndrome. Both conditions can be fatal if not treated.1


There are two types of beriberi - wet beriberi and dry beriberi.6

Wet beriberi affects the heart and circulatory system and in extreme cases can cause heart failure.6

Dry beriberi damages the nerves and can lead to decreased muscle strength and eventually, muscle paralysis.6

Wernicke–Korsakoff’s syndrome

Wernicke-Korsakoff’s syndrome most commonly occurs in alcohol-dependent people.

This nerve and brain disease is made up of two conditions/phases – Wernicke encephalopathy, which occurs first and then progresses to Korsakoff’s syndrome.1

Wernicke’s encephalopathy is life threatening. Symptoms include:

  • confusion 
  • loss of memory activity
  • loss of muscle coordination and leg tremors
  • double vision, abnormal eye movements or eyelid drooping.1,4

Wernicke’s encephalopathy is usually reversible through treatment but can progress to Korsakoff’s syndrome - a chronic and disabling condition characterised by severe short-term memory loss, hallucinations and impaired ability to acquire new information.1

Treating thiamine deficiency

Thiamine deficiency can be treated by stopping alcohol consumption, eating a nutritious diet and by taking vitamin B1 supplements.1

However, diet and supplements alone are not effective if heavy alcohol use continues because alcohol will block absorption. 

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

  1. National Institute of Health (NIH). Thiamin [Accessed 27 October 2021]. 
  2. Medline Plus. Thiamin [Accessed 27 October 2021]. 
  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 [Accessed 27 October 2021]. 
  4. Medline Plus. Wernicke-Korsakoff syndrome [Accessed 27 October 2021]. 
  5. Healthline. 11 Signs and Symptoms of Thiamine (Vitamin B1) Deficiency [Accessed 27 October 2021]. 
  6. National Health and Medical Research Council (NHMRC). Thiamin [Accessed 27 October 2021]. 

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