Has folate a role in the developing nervous system after birth and not just during embryogenesis and gestation?

It is now 30 years since the first publications stating that supplementation with folate could prevent neural tube defects appeared and 20 years since the definitive data, including prevention of other birth defects. Since then epidemiological studies and animal experiments have identified folate as a molecule at the crossroads of neural development. Fortification of food has greatly reduced the incidence of spina bifida. Much interest has focussed on long-term sequelae in children born to mothers severely deprived of folate (and other nutrients) such as during the Dutch Hunger Winter of 1944 and in poor parts of the world. In addition, deficiency in folate and B12 are increasingly discussed as a possible contributing factor in dementia and congenital orofacial and heart malformations. The year 2011 saw the publication of a study that implicated low folate intake in poorer school performance of adolescents as judged by school marks. This has enormous social implications but needs confirmation from other settings. This review assesses the current state of evidence and sets the data in context of whether folate has a role in the development and plasticity of the nervous system even after birth, with particular emphasis on childhood and adolescence.