tiamina

Tiamina, also known as thiamine or vitamin B1, is an essential water-soluble nutrient required by humans. It plays a critical role in energy metabolism and nerve function, primarily through its active coenzyme form, thiamine pyrophosphate (TPP). TPP participates in the decarboxylation of pyruvate and in the metabolism of branched-chain amino acids and sugars, and it is a cofactor for the transketolase enzyme in the pentose phosphate pathway. Adequate thiamine is necessary for normal function of the nervous system and for the production of adenosine triphosphate (ATP).

Tiamina cannot be synthesized by the human body and must be obtained from the diet. Common sources include pork, fortified cereals and breads, legumes, whole grains, seeds, and nuts. Because it is water-soluble and sensitive to cooking, thiamine content in foods can be reduced by prolonged heat or alkaline conditions. Recommended intakes vary by age, sex, and life stage; typical values for adults are around 1.1–1.2 mg per day, with higher amounts during pregnancy and lactation.

Deficiency can lead to beriberi, which may present in dry (neurological) or wet (cardiovascular) forms, and to Wernicke-Korsakoff syndrome, especially in people with chronic alcohol use. Symptoms include fatigue, weakness, neuropathy, edema, and confusion. Diagnosis is usually clinical and may involve laboratory tests such as thiamine or thiamine diphosphate levels and erythrocyte transketolase activity.

In clinical practice, thiamine is administered orally or by injection to treat or prevent deficiency. It is generally well tolerated, with excess thiamine excreted in urine; no established upper intake level is set due to low risk of toxicity.