Vitamin B1 (Thiamin)

Vitamin B1 is thiamin, a small molecule containing a sulfur (thiol) group and a nitrogen (amine) group. Vitamin B1 has many roles in cells, the most important of which is being a cofactor in the production of acetyl coenzyme-A, which is essential for energy production in the body (specifically the production of ATP). Thiamin also acts as a cofactor in the synthesis of both DNA and RNA and is additionally involved in nerve function. 

The disease associated with thiamin deficiency is called beriberi, and can present itself in four forms - dry, wet, infantile, and cerebral (also called Wernicke-Korsakoff syndrome). Dry beriberi involves muscle atrophy, while wet beriberi involves swelling of the arms and legs and respiratory and heart problems. Whole grains are an excellent source of thiamin, as are pork and poultry.