Potential risks of folic acid supplementation and food enrichment
THE CONTEXT
Folic acid enrichment can prevent neural tube defects, but the passage identifies groups in whom high intake may create problems.
Masking vitamin B12 deficiency
•
Folic acid supplements rectify megaloblastic anemia caused by vitamin B12 deficiency but do not rectify irreversible nerve damage.
•
High folic acid intake can therefore mask vitamin B12 deficiency.
•
Elderly people are particularly vulnerable: age-associated atrophic gastritis causes failure of gastric acid secretion and prevents release of vitamin B12 from dietary proteins.
•
Concern about masking vitamin B12 deficiency contributes to differences between countries in adopting mandatory folic acid enrichment of flour.
Other concerns
•
Folic acid antagonizes some anticonvulsants used to treat epilepsy.
•
Some evidence suggests that folate supplements may increase colorectal cancer risk in people with preneoplastic colorectal polyps.