Vitamin B1 (Thiamin)

Vitamin B1 plays an important role in carbohydrate metabolism. As a component of a coenzyme it acts to release energy from carbohydrates. The amount of Vitamin B1 required in the body is related to the amount of carbohydrate that is eaten in the diet. Vitamin B1 subsequently plays a role in the nervous system, because nerves, tissues and muscles rely heavily on the energy produced from the metabolism of carbohydrates.

Recommended daily intakes of (RDI) Vitamin B1 (mg/day)


Age (years)










In the most recent National Nutrition Survey the median intake of Vitamin B1 in New Zealanders was 1.4 mg/day.

Vitamin B1 deficiency

Deficiency of Vitamin B1 is now very uncommon in the western world, although it can be seen in older people or people who suffer from chronic alcoholism. The disease associated with Vitamin B1 deficiency is beri-beri, a disorder of the nervous system affecting the workings of the heart and muscles. An associated condition, most commonly seen in alcoholics, is Wernicke’s disorder, which affects brain function after prolonged Vitamin B1 deficiency.

Food sources of Vitamin B1

Good sources of Vitamin B1 are wholegrain cereals, pork, dried peas and beans. The main dietary sources of Vitamin B1 in the New Zealand diet are bread, potatoes, breakfast cereals and vegetables.

25% of Vitamin B1 is lost from foods on cooking, especially meat and vegetables. Vitamin B1 leaches into water when foods are blanched or boiled for a prolonged period. The amount of Vitamin B1 lost can be reduced by using a microwave or small amounts of water when cooking.