Thiamine: What It Is, Beriberi And Vitamin B1 Foods

Thiamine (vitamin B1) is an essential nutrient whose deficiency is associated with beriberi disease.

Thiamine is a water-soluble micronutrient that is involved in key processes in our body, such as the conversion of glucose into biological energy. Its function in our body is so crucial that the deficiency of this vitamin can cause severe conditions such as Wernicke-Korsakoff syndrome or optic neuropathy.

In this article, we will talk about what it is and what it does, what happens if we have thiamin deficiency and vitamin b1 foods we can find. In the end, we will detail what the commonly recommended amounts of thiamine are.

What is thiamine (vitamin B1)?

Thiamine, also known as thiamin or vitamin B1, was the first from the vitamin B complex to be discovered. In most of the natural foods, as well as in the multivitamin supplements, it usually comes with the rest of type B vitamins.

The vitamin B complex includes vitamin B1 or thiamine, vitamin B2 or riboflavin, vitamin B3 or niacin, vitamin B5 or pantothenic acid, vitamin B6 or pyridoxine, vitamin B9 or folic acid, and vitamin B12 or cyanocobalamin.

Specifically, thiamine  corresponds to an essential component of an enzyme: thiamine pyrophosphate. It is directly involved in carbohydrate metabolism, which is one of our body's primary sources of energy.

What does thiamine do?

Vitamin B1 works with other B complex vitamins  to help our organism in the use of proteins and fats; as well as to keep the mucous membranes and the heart healthy. 

In general, our brain depends on its role to be able to carry out the process of converting glucose into biological energy for its proper functioning. It also takes part in some key metabolic reactions that take place in:

  • The nervous tissue

  • The heart

  • Red blood cell production

  • Maintenance of muscle and skeletal tissue

It is also used to treat thiamine deficiency; a condition we will talk about in the following lines, and that can lead to very severe consequences if the deficiency is serious. This micronutrient is also included in the treatment of other conditions such as some types of pathologies of the urinary tract, for example, the Leigh syndrome. 

Insomnia is one of the main consequences of thiamine deficiency.
Insomnia is one of the main consequences of thiamine deficiency.

Thiamine deficiency symptoms (beriberi disease)

Thiamine deficiency, in mild cases, can cause general discomfort, weight loss, irritability, and confusion. However, in the most complex situations, it can cause a disease known as beriberi. This syndrome generally causes symptoms such as:

  • Appetite loss

  • Abdominal pain

  • Enlargement of the heart

  • Constipation

  • Weakness

  • Swelling of the extremities

  • Muscle spasms

  • Insomnia

  • Memory loss

The beriberi syndrome that is not treated correctly can lead to the Wernicke-Korsakoff syndrome. People with this pathology can experiment symptomatology such as confusion, hallucinations, and disability to speak, among others; even progressing to coma and/or death.

As it has been studied, the main risk factor to develop a vitamin B1 deficiency is chronic alcoholism. This is because of the general dietetic consumption low in thiamine and other vitamins, adding to the fact that alcohol increases the excretion of vitamin B1. In addition, affections such as cirrhosis, diabetes, chronic infections or other kidney diseases are also factors associated with the deficiency of this nutrient in the organism. 

Foods high in thiamin

Thiamine is a nutrient that, like other B vitamins, can be found in many natural foods, as well as through vitamin supplements for those people with lack of vitamin B1 or who have conditions that favor vitamin B1 deficiency. Below we will show these  two main sources of thiamine.

Natural sources: food and nutrients

Although this micronutrient is usually found in many foods, especially those of vegetal origin, with the exception of animal liver. Foods with higher amounts of vitamin B1 are these:

  • Fortified wholemeal products (bread, cereals, rice...)

  • Nuts

  • Legumes

  • Wheat germ

  • Beef and pork liver

  • Sunflower seeds

  • Dates

  • Alfalfa

It is also important to know that vitamin B1 foods are very poorly resistant to certain cooking conditions, such as heat. When cooking at very high temperatures, it is eliminated, and that is why this type of food should be cooked on low heat, as well as using steam cooking.

Vitamin B1 foods include whole grains and nuts.
Vitamin B1 foods include whole grains and nuts. 

Supplementary sources

Due to multiple external conditions and factors such as the consumption of fast food and low in nutrients, drinking alcohol or suffering from diabetes, people can have a lack of this vitamin. In these cases, the use of supplements of this nutrient is recommended.  

They are available in oral, intramuscular and intravenous formulations. Injectable types are generally recommended for people with very severe thiamine deficiencies.

Recommended amounts

The daily recommended thiamine amount for up to 6 months-old babies is usually 0.3 mg; 0.4 mg for babies between 6 months and 1 year old; 0.7 mg for children between 1 and 3 years old, 0.9 mg for those between 4 and 6, and 1 mg for children between 7 and 10 years old.

When children get to 10, variations in the recommended amounts according to sex begin to appear. Children from 11-14 years old need more or less 1.3 mg every day; 1.5 mg for men between 15 and 50; and 1.2 mg for those who are older than 50.

Girls and women between 11 and 50 years old only need 1.1 mg of thiamine a day. This dose is slightly higher for pregnant (1.5 mg) or nursing (1.6 mg) women.

Explicitly,  it is said that adults in general need a minimum of 1.0 mg of vitamin B1 every day. But the dose can be increased by 0.5 mg per 1,000 calories of daily dietary intake on a basis of 2,000 calories.


Turner, J. (2002). Thiamine. In K. Krapp (Ed.), The Gale Encyclopedia of Nursing and Allied Health (Vol. 5, pp. 2412-2414). Detroit: Gale.

Turner, J., & Frey, R. J. (2005). Thiamine. In J. L. Longe (Ed.), The Gale Encyclopedia of Alternative Medicine (2nd ed., Vol. 4, pp. 2008-2010). Detroit: Gale.