Folic Acid

Summary Folic acid exists in many different chemical forms in living tissues, and it takes part in a wide variety of biochemical and physiological processes, many of which are, at present, incompletely understood. Recent observations suggest it may fulfil important functions in the brain, as well as in haemopoietic and gastrointestinal tissues, with pathological consequences for subjects who are folate deficient, either through dietary insufficiency, or through drug‐induced or genetically determined increases in requirements. The currently available information about the folate content of foods is unsatisfactory, and the levels may, for technical reasons, have been considerably underestimated. Likewise, the available information about minimum human requirements is incomplete, and it is therefore impossible to accept current recommendations of advisable intakes without reservation. The potential importance of folate status, particularly with regard to early fetal development, renders this subject extremely important, and ripe for reappraisal and reinvestigation.