Vitamin B is a family of vitamins, all water soluble, somewhat related in function and often occurring together in foods. They include vitamin B1 (thiamin), vitamin B2 (riboflavin), vitamin B6 (pyridoxine), vitamin B12 (cobalamin), vitamin B3 (nicotinic acid), folacin (folic acid), also called pteroylglutamic acid or PGA), pantothenic acid and biotin.