The primary biochemical function of folic acid is related to the transfer of single carbon in the synthesis of a number of metabolites in the body. Along with vitamin B12 folic acid is connected with the synthesis of nucleic acid. After absorption, folic acid undergoes a series of metabolic conversions to its various coenzymic forms. Folic acid requirements are expressed in terms of ‘free’ folic acid which is readily absorbed. Folic acid allowances (?g/day) are as follows: