It has been established that gestational folic acid reduces the risk for neural tube defects, but it also increases postnatal cortical thickness and delays the onset of cortical thinning, therefore reducing the risk for psychosis, according to a study published in JAMA Psychiatry.
This retrospective study evaluated magnetic resonance imaging scans of 8- to 18-year-olds who were born between January 1993 and December 2001. The United States government mandated that all grain products be fortified with folic acid by January 1, 1998, which lead to the creation of 3 cohorts: nonexposed (n=97), partially exposed (n=96), and fully exposed (n=99). The primary analysis was mean cortical thickness.
Differences in cortical thickness were found in the bilateral frontal and inferior temporal regions. The fully exposed cohort had a thicker cortex than the partially exposed, and the partially exposed had a thicker cortex than the nonexposed. When age-associated changes were taken into account, the fully exposed cohort had a significant delay in cortical thinning compared with the nonexposed cohort. Many child-onset psychoses are associated with loss of brain tissue. This suggests a potential protective effect of adding folic acid to a pregnant mother’s diet. Because this study is retrospective, there could be temporal confounding variables and discrepancies in particular maternal diets. The specific mechanisms for these results do warrant further evaluation.
In conclusion, these “findings suggest that protective effects of prenatal folic acid exposure may extend beyond prevention of neural tube defects and span neurodevelopment during childhood and adolescence.”
Eryilmaz H, Dowling KF, Huntington FC, et al. Association of prenatal exposure to population-wide folic acid fortification with altered cerebral cortex maturation in youths [published online July 3, 2018]. JAMA Psychiatry. doi:10.1001/jamapsychiatry.2018.1381