Vitamin B1, molecular model. The chemical formula for vitamin B1, also called thiamine, is C12.H17.N4.O.S. Atoms are represented as spheres and are colour-coded: carbon (blue), hydrogen (gold), nitrogen (dark blue), oxygen (red) and sulphur (yellow). Vitamin B1 is an essential nutrient that humans are unable to produce and so need to obtain from their diet. It is found in flour, beans, pork, and salmon. Vitamin B1 is important for the normal function of the heart, muscles and nervous system, as well as normal growth and development. Deficiency can lead to the disease beriberi, which causes weight loss, emotional disturbances, and limb pain and weakness.