<P> B vitamins are a class of water - soluble vitamins that play important roles in cell metabolism . Though these vitamins share similar names, they are chemically distinct that often coexist in the same foods . In general, dietary supplements containing all eight are referred to as a vitamin B complex . Individual B vitamin supplements are referred to by the specific number or name of each vitamin: B = thiamine, B = riboflavin, B = niacin, etc . Some are better known by name than number: niacin, pantothenic acid, biotin and folate . </P> <P> Each B vitamin is either a cofactor (generally a coenzyme) for key metabolic processes or is a precursor needed to make one . </P>

How many types of vitamin b do we have