Vitamin B1 or thiamine is water-soluble. Very little thiamine is stored in the body; very small amounts are taken up in the small intestine (jejunum), even if large amounts are present in the intestine. For these two reasons, daily intake is necessary. Vitamin B1 has a low heat-resistance (destroyed around 100°C); cooking foods in water is thus the cause of most vitamin B1 losses. Indeed, firstly, heat destroys the vitamin and, secondly, as it is water-soluble, it is lost in the cooking water.

Roles

Energy production : vitamin B1 is involved, as a co-enzyme, in the metabolism and uptake of carbohydrates, fat and protein obtained from dietary sources.

Nervous system : thiamine is involved in the conduction of nerve impulses. Thiamine supports normal psychological functions such as memory, reasoning and concentration.

Vitamin B1 supports a normal energy metabolism.

Table of RNI (Reference Nutrient Intakes) for vitamin B1 :

Age / Status	RNI for vitamin B1
Infants	0,2 mg
Children from 1 to 3 years	0,4 mg
Children from 4 to 12 years	0,6 à 1 mg
Teens from 13 to 19 years	1,1 à 1,3 mg
Women	1,1 mg
Men	1,3 mg
Pregnant women	1,8 mg
Breastfeeding women	1,8 mg
Seniors	1,2 mg