What is thiamine?

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.

How does thiamine work in the body?

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.

Benefits of Thiamine

• 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

Recommended daily intake

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.

Natural sources of thiamine

• Whole grain products (oats, spelt, wheat germ, brown rice)

• Legumes (lentils, peas, beans)

• Pork, poultry

• Sunflower seeds, nuts (especially cashews)

• Potatoes, asparagus, spinach

Deficiency symptoms

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)

Overdose and safety

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.

Conclusion

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.

Sources

1. German Nutrition Society (DGE). (2020): Reference values ​​for nutrient intake – Thiamin.

2. 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.

3. Singleton CK, Martin PR. (2001): Molecular mechanisms of thiamine utilization. Curr Mol Med , 1(2), 197–207.

4. Frank LL. (2015): Thiamine in clinical practice. J Parenter Enteral Nutr , 39(5), 503–520.