Vitamin b1

Vitamin B1 is a water-soluble, heat-sensitive (is destroyed by boiling) and UV radiation-sensitive substance with the molecular formula C12H17N4OS, which is easily destroyed by oxidants and bases. Vitamin B1 plays an important role in cell metabolism, especially in its active coenzyme form as thiamine diphosphate.

Structurally, thiamine consists of two ring systems connected by a methylene bridge: a pyrimidine ring and a thiazole ring (see figure). Thiamine is absorbed in the intestine by a thiamine transporter.

In thiamine-responsive megaloblastic anaemia (TRMA), several mutations in the SLC19A2 gene have been detected. These mutations lead to the inability of the thiamine transporter to function. As a result, thiamine can no longer be sufficiently absorbed from the intestine. This resorption disorder induces the clinical picture of TRMA (diabetes mellitus type 1, deafness, megaloblastic anaemia, cardiac dysfunction), which leads to death if left untreated.

Thiamine occurs naturally in plant and animal tissues in varying concentrations, such as in high concentrations in yeast, in the silverskin of the rice grain and in wheat, rye and barley seedlings. Furthermore, egg yolk, milk, liver, kidney, potatoes, asparagus, spinach, nuts and fish are rich in vitamin B1.

Needs:

• Infants (up to 12 months): 0,2-0,4 mg/day
• Children (1-15 years):
  • female: 0,6-1,1 mg/day
  • male: 0,6-1,4 mg/day
• Women: 1.0 mg/day
• Pregnant women (from 4th month): 1,2 mg/day
• Men 1.0-1.3 mg/day

Vitamin B1 deficiency (Beri-Beri ): A vitamin B1 deficiency (Thimain deficiency) does not occur with a balanced diet. The greatest risk is posed by the very rare mutation in the SLC19A2 gene, which leads to a functional incapacity of the thiamine transporter, or in severe alcoholism (de la Monte SM et al. 2014). Neurological (Abdul-Muneer PM et al. 2018) and cardiac symptoms are in the foreground.

Vitamin B1 overdoses: Symptoms of overdoses in case of excessive intake with food are not known so far.

1. Abdul-Muneer PM et al (2018) Impairment of Thiamine Transport at the GUT-BBB-AXIS Contributes to Wernicke's Encephalopathy in chronic alcohol users. Mol Neurobiol. 2017 Nov 11. doi: 10.1007/s12035-017-0811-0.
2. Ammon H et al (2014). Hunnius Pharmaceutical Dictionary. Walter de Gruyter GmbH . Berlin/Boston S 1894-1895
3. de la Monte SM et al (2014) Human alcohol-related neuropathology. Acta neuropath 127:71-90.