Thiamine (vitamin B1) is a water-soluble vitamin. It is essential for the body’s energy supply and for the proper functioning of the heart muscle and nervous system.
Thiamine was formerly known as “aneurine” or the “antiberiberi” vitamin.
Thiamine is found in a variety of animal and plant-based foods: wholegrain products, potatoes, meat, legumes, milk and dairy products.
A thiamine deficiency can cause abnormalities of the nervous system and psychological abnormalities.
Functions of Vitamin B1
Thiamine has several well-documented functions in the body. It is needed to convert carbohydrates into energy, which is crucial for overall metabolism. Additionally, thiamine is important for the proper functioning of the heart, nervous system, and brain.
Absorption of Vitamin B1
The human body absorbs thiamine efficiently. However, only small amounts are stored in the liver, which means that regular intake of thiamine-rich foods is necessary. Any excess thiamine is excreted through urine, making overconsumption unlikely to cause harm to health.
How Much Thiamine Do You Need Per Day?
The amount of thiamine you need depends on the energy (calories) you consume through your diet. The Health Council of the Netherlands provides the recommended daily intake (RDA) for thiamine based on the amount of energy consumed, rather than an absolute number. For the adult population, the RDA is approximately 0.1 milligrams per megajoule (0.1 mg/MJ). For example, if a person’s energy requirement is 2,000 kilocalories per day:
1 kilocalorie = 4.2 kilojoules, so 2,000 kilocalories = 2,000 x 4.2 = 8,400 kilojoules (or 8.4 megajoules).
Therefore, the recommended daily intake for this specific person would be: 0.1 x 8.4 = 0.8 milligrams of thiamine.
While this formula can seem complicated, you can simplify it by remembering that the recommended daily intake for thiamine is about 1 mg for the average adult.
Sources of Vitamin B1
Thiamine is naturally found in meats, fish, whole grains, legumes, and seeds. However, thiamine can be destroyed by high-heat cooking or long cooking times. It may also be lost during food processing (for example, in refined white bread, pasta, and white rice). As a result, in some countries, thiamine is added back (enriched) to processed foods such as bread and cereals.
Lentils are an excellent source of thiamine, providing up to 1 mg per 100 grams. Another great source is sunflower seeds, which provide 0.9 mg of thiamine per 50 grams.
What Are the Consequences of a Thiamine Deficiency?
A thiamine deficiency can lead to psychological disorders, such as depression, memory problems, and difficulty concentrating. Severe malnutrition and a lack of thiamine can cause a disease called beriberi, which is characterized by swelling, tingling or burning sensations in the hands and feet. While beriberi is uncommon in Europe, it remains a concern in developing countries.
Thiamine deficiency is also common among specific risk groups, such as alcoholics, drug addicts, individuals with gastrointestinal disorders such as Crohn’s disease and persons suffering from eating disorders, specifically anorexia. In severe cases, it can lead to Wernicke-Korsakoff syndrome. Wernicke-Korsakoff syndrome (WKS) is a serious neurological disorder, often associated with chronic alcohol consumption or malnutrition. It consists of two distinct phases: Wernicke encephalopathy and Korsakoff syndrome. Wernicke encephalopathy is characterized by symptoms such as confusion, difficulty with muscle coordination (ataxia), and abnormal eye movements (nystagmus). If left untreated, it can progress to Korsakoff syndrome, which involves severe memory problems, including anterograde amnesia (difficulty forming new memories) and retrograde amnesia (loss of past memories). People with Korsakoff syndrome may also exhibit confabulation, where they create false memories to fill in gaps in their recollection. Without prompt treatment, Wernicke-Korsakoff syndrome can result in long-term cognitive impairments and physical disabilities.
What Are the Consequences of Too Much Thiamine?
The body only absorbs a small amount of thiamine, which is then excreted through urine. There are no known harmful effects from consuming too much thiamine. In fact, because thiamine is non-toxic even at high doses, it has been used therapeutically to treat chronic cluster headaches and certain neurodegenerative diseases.
Because thiamine has a high safety profile, no upper intake limit has been established.
Vitamin B1: Considerations for Vegans/Vegetarians
Thiamine is found in a variety of plant-based foods. Observational studies do not show that people who follow a vegetarian or a vegan diet have a higher risk of developing B1 deficiency. However, persons who follow a very strict diet devoid of grains and legumes, are more likely not to meet daily needs of thiamine. Therefore, vegetarians and vegans should ensure they consume a variety of thiamine-rich foods.