Vitamin B1. Computer model of a molecule of vitamin B1 (thiamine, C12.H17.N4.O.S), a water- soluble vitamin. The atoms (solid tubes) of this organic molecule are colour-coded: oxygen (red), carbon (yellow), hydrogen (grey), nitrogen (blue) and sulphur (green). Thiamine is important for the normal function of the heart, muscles and nervous system, as well as normal growth and development. Flour, beans, pork and salmon provide thiamine. An excessive deficiency of thiamine can result in the disease beriberi. Small amounts of vitamins are an essential part of a healthy diet, providing enzyme cofactors for the varied biochemistry of body metabolism.