Associations between nutrient levels during pregnancy and DNA methylation have also been assessed using blood. A number of previous groups have described importance of folate as a key nutrient involved in the process of establishing and maintaining DNA methylation (Chmurzynska, 2010). Ba and colleagues used both maternal blood and umbilical cord blood to measure specific gene promoter methylation in insulin-like growth factor 2 (IGF2), which is believed to be a major growth factor in the developing fetus (Ba et al., 2011). Amongst their findings, they found that while P2 and P3 methylation in cord blood was not significantly associated with folate levels in either cord blood or maternal blood, P3 methylation was significantly associated with vitamin B12 serum levels in maternal blood. Furthermore, P2 methylation in mother’s blood was associated with vitamin B12 maternal blood serum levels, passive smoke exposure, and maternal weight gain during pregnancy. While not focused on smoking during pregnancy per se, the investigators did consider passive smoke exposure, which is an indication of secondhand smoke exposure during pregnancy. Further, their study underscores the importance of environmental exposures and maternal dietary factors in potentially mediating methylation patterns in specific biological pathways.
