Thiamin , also known as vitamin B1 , is an essential, water-soluble vitamin from the B complex that plays a crucial role in energy metabolism, nerve function, and cognitive performance . Because the body cannot store thiamin and it is continuously excreted in urine, a regular intake through food or supplements is necessary.
Thiamine was the first B vitamin to be identified, hence its designation "B1" . It is found primarily in whole grains, legumes, meat (especially pork) , and nuts . In its active form – thiamine pyrophosphate (TPP) – it acts as a coenzyme in numerous biochemical reactions that release energy from carbohydrates and amino acids.
A deficiency of thiamine can have far-reaching consequences, as organs with high energy demands – especially the brain, heart and muscles – depend on a constant energy supply.
1. Energy production from carbohydrates:
Thiamine is an essential component of the pyruvate dehydrogenase complex enzyme, which enables the conversion of carbohydrates into energy (ATP) . Without thiamine, glucose cannot be efficiently utilized in the mitochondria, leading to energy deficiency, fatigue, and muscle weakness .
2. Support of the nervous system:
Thiamine plays a central role in the transmission of nerve impulses between nerves and muscles . It is necessary for the synthesis of neurotransmitters such as acetylcholine, which are responsible for memory, concentration, and motor control.
A deficiency can lead to nerve damage , numbness , coordination problems , or even neurological diseases such as beriberi or Wernicke-Korsakoff syndrome .
3. Heart and muscle function:
Thiamine supports heart muscle contraction and helps maintain healthy cardiovascular function. A thiamine deficiency can lead to heart enlargement, edema, and shortness of breath because the heart works less efficiently.
4. Supporting the metabolism of amino acids and fatty acids:
Thiamin is involved in the utilization of amino acids and the breakdown of fatty acids . It thus supports the provision of energy from various nutrient sources.
5. Antioxidant effect and protection against cell stress:
Thiamine indirectly contributes to the reduction of oxidative damage , as it optimizes energy metabolism as a coenzyme and supports the production of reducing equivalents (NADPH) – substances that protect cells from free radicals.
Converts carbohydrates into energy and supports energy metabolism
Promotes normal nerve and brain function
Supports heart and muscle function
Contributes to mental performance and concentration
Reduces tiredness and fatigue
Protects cells from oxidative stress
Improves glucose utilization and supports blood sugar balance
According to the German Nutrition Society (DGE) :
Men: 1.2–1.3 mg per day
Women: 1.0–1.1 mg per day
Increased need for athletes, pregnant women, breastfeeding women and people with high carbohydrate intake.
Since thiamin is water-soluble, it is easily lost during cooking – gentle cooking or steaming is therefore recommended.
Whole grain products (oats, spelt, wheat germ, brown rice)
Legumes (lentils, peas, beans)
Pork, poultry
Sunflower seeds, nuts (especially cashews)
Potatoes, asparagus, spinach
Thiamine deficiency can be caused by inadequate nutrition, chronic alcohol abuse, digestive disorders, or increased physical stress.
Symptoms:
Fatigue, muscle weakness
Irritability, concentration problems
Loss of appetite
Heart problems, edema
Neurological disorders (e.g., tingling, numbness, ataxia)
Severe deficiencies lead to diseases such as:
Beriberi (dry form: nerve damage; wet form: heart failure)
Wernicke-Korsakoff syndrome (especially in alcoholics – with memory loss and disorientation)
An overdose is practically impossible, as excess thiamine is excreted via the urine.
Even high doses (>50 mg) are well tolerated and are usually used therapeutically in cases of deficiency.
Thiamin (vitamin B1) is a key factor for energy production, nerve function, and heart health . Without sufficient thiamin intake, the body cannot efficiently convert carbohydrates into energy, which quickly leads to noticeable fatigue, especially in active people, athletes, or those with an unbalanced diet.
A conscious diet rich in whole grains, legumes, and high-quality protein sources reliably covers the body's needs. As a supplement, thiamin contributes to boosting energy, concentration, muscle strength, and mental clarity – essential for vitality and performance in everyday life and training.
German Nutrition Society (DGE). (2020): Reference values for nutrient intake – Thiamin.
Lonsdale D. (2006): A review of the biochemistry, metabolism and clinical benefits of thiamine(e) and its derivatives. Evid Based Complement Alternat Med , 3(1), 49–59.
Singleton CK, Martin PR. (2001): Molecular mechanisms of thiamine utilization. Curr Mol Med , 1(2), 197–207.
Frank LL. (2015): Thiamine in clinical practice. J Parenter Enteral Nutr , 39(5), 503–520.
