Rethinking Folic Acid Fortification: A Pharmacogenomic and Policy-Based Reappraisal of Neural Tube Defect Trends

This investigative research critically re-evaluates the widely accepted attribution of reduced neural tube defect (NTD) rates in Canada to folic acid fortification. Drawing on a parallel timeline analysis, the study identifies and contextualises several significant pharmacological and regulatory changes - specifically the concurrent withdrawal or restriction of known teratogenic anticonvulsants - that occurred during the implementation of fortification policy. The analysis integrates historical prescribing data, known teratogenic mechanisms, and the chronological overlap of drug market exits with declining NTD incidence. Evaluation reveals that these co-occurring variables represent substantial confounding factors. In addition, the paper incorporates a research synthesis on the biochemical limitations of synthetic folic acid, including the role of unmetabolised folic acid (UMFA), differential receptor binding, and genetic utilisation variance. The collated findings challenge the prevailing narrative that fortification was responsible for improved NTD outcomes and suggest an ongoing triple hit hypothesis; involving MTHFR susceptibility, anti-seizure medication (ASM) exposure, and hidden folate and B12 insufficiency as a plausible driver of paradoxical neural tube defect trends in the UK. This compilation highlights that a reassessment of causality is required in population-level nutrition policy to safeguard public health. Pharmacogenomic and nutritional profiling, including assessment of B12 and folate sufficiency, should be prioritised in women of reproductive age before the prescribing of anti-seizure medications. This analysis underscores the need for rigorous pharmacological context in public health modelling and offers an evidence-based call for transparency in attributing outcomes to broad scale interventions.