Serum folate but not vitamin B-12 concentrations are positively associated with cognitive test scores in children aged 6-16 years.

Folate and vitamin B-12 are important for nervous system functioning at all ages, with important roles in functions such as neurotransmitter synthesis. Although studies suggest a relation between folate and vitamin B-12 and cognitive function in the elderly population, there is relatively less evidence regarding these vitamins and children's cognitive function. The purpose of the study was to examine the associations of serum folate and vitamin B-12 with cognitive performance in children 6-16 y old in the NHANES III, conducted from 1988 to 1994, prior to the implementation of folic acid fortification. A cross-sectional analysis was conducted using data on 5365 children 6-16 y old from NHANES III. Serum folate and vitamin B-12 concentrations were measured, along with performance, on the Wide Range Achievement Test-Revised and the Wechsler Intelligence Scale for Children-Revised. Associations of B vitamins with cognitive performance were assessed using linear regression models adjusted for various covariates. Higher serum concentrations of folate were associated with higher reading and block design scores after adjusting for various covariates. For example, compared with the lowest quartile of folate, children in the highest quartile scored 3.28 points or 0.19 SD units higher on the reading test (P < 0.05). Vitamin B-12 was not associated with any of the test scores. In the largest study to date, higher folate concentrations were associated with better reading and block design scores. These associations appear to be biologically plausible and merit further study.