Chromatin changes after long term vitamin D supplementation

In this study, we investigate the long-term in vivo modulation of the human epigenome following vitamin D₃ supplementation. Specifically, we analyse epigenetic changes in peripheral blood mononuclear cells (PBMCs) collected 84 days after administration of a single bolus dose of vitamin D₃ (1,000 IU/kg). Vitamin D is a well-known regulator of gene expression through the vitamin D receptor (VDR), which interacts with chromatin and modulates the epigenetic landscape of immune cells. However, the persistence and extent of these epigenomic effects in vivo remain insufficiently characterized.To address this question, we assess genome-wide epigenetic alterations in PBMCs to determine whether a single high dose of vitamin D₃ induces sustained modifications in regulatory regions associated with immune function and cellular signalling pathways. The study focuses on identifying changes in chromatin accessibility and regulatory element activity that may reflect long-lasting transcriptional priming of immune cells. This work represents a continuation of the VitDPAS study, which previously examined the immediate molecular responses to vitamin D₃ supplementation. By extending the analysis to the 84-day time point, the present study aims to determine whether the epigenetic effects of vitamin D₃ persist over the long term and contribute to prolonged immune modulation. Understanding these sustained epigenomic changes may provide new insights into the mechanisms through which vitamin D influences immune regulation and long-term health outcomes.