Folic acid: miscarriages, anomalies, thromboses, cancers.

Folic acid is an essential micronutrient that merits special attention. In spite of plentiful sources in a balanced diet, recent data indicate that folic acid intake of many persons has long been inadequate. To some degree, this is due to destruction of folic acid by storage and processing of foodstuffs and to dietary practices that vary from recommendations. However, the common hereditary thermolabile variant of methylenetetrahydrofolate reductase (MTHFR) imposes an increased folic acid requirement which, if not met, may result in recurrent early pregnancy loss, anomalous progeny, thrombotic disorders, and cancers. There are recent reports that folic acid metabolism is also altered by other hereditary variations of MTHFR and other enzymes involved in folic acid metabolism. Optimal management requires dietary guidance and, for many patients, folate supplements. Caution is required because mandated folate fortification of grain products may produce levels that are inadequate for some patients and excessive for others. Laboratory tests for red cell folate and serum homocysteine are valuable adjuncts.