Thiamin, or vitamin B1 is involved in metabolism. It is part of a coenzyme (a compound that aids enzymes in activating reactions) involved in energy metabolism reactions. It is also involved in nerve transmission.
Thiamin is water-soluble and is absorbed in the small intestine. Approximately half of the thiamin in the body is stored in muscle. However, thiamin does not remain in the body for long and must be continually replenished.
The richest sources of thiamin include yeast, wheat germ, pork, organ meats, liver, eggs, cereals, berries, green leafy vegetables, nuts and legumes.
Milling grains removes portions rich in thiamin. Therefore, in populations where white rice is a staple, it is important to get thiamin from other sources. Thiamin deficiency is known as beriberi. Dry beriberi includes paralysis and muscle atrophy. Wet beriberi is characterized by congestive heart failure, cardiac dilation and serious edema (swelling due to water retention). In infants, beriberi results in cardiac failure.