Malnutrition: folate and cobalamin deficiency.

Malnutrition of folate and cobalamin occurs on a world-wide scale. Millions of individuals, for a variety of cultural, religious and socio-economic reasons, ingest less than the daily amounts required to maintain body stores. Assessment of intake depends on the population under study, method of food preparation and assay technique. Up to 90% of folate may be destroyed by cooking and, although less, significant amounts of cobalamin can also be lost in this way. Estimates of the proportion of both vitamins absorbed from a mixed diet vary, but may be as little as 50%. The need for supplementation is more common with folate than cobalamin. However, recent advances have highlighted subtle sub-clinical metabolic changes in some groups, particularly the elderly. Further investigation into their requirements is indicated. New assays for metabolites of cobalamin and folate are highly sensitive but lack specificity and are not readily available.