Vitamin D: A Classic Case of Nutrigenomics

Nutrigenomics aims to characterize and integrate the relationship between dietary molecules and gene expression at the genome-wide level. Vitamin D3 is a bioactive nutritional compound that activates the nuclear receptor VDR (vitamin D receptor) through its metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). Vitamin D3 can be synthesized endogenously in our skin, but because we spend long periods indoors and often live in high-latitude regions with lower UV-B radiation in winter, it becomes a true vitamin. The ligand-induced transcription factor VDR is expressed in most human tissues and cell types and regulates the epigenome at thousands of genomic sites. This regulation leads to up- and down-regulation of major vitamin D target genes in a tissue-specific manner, some of which target genes participate in reducing oxidative stress. Vitamin D affects multiple physiological functions, including metabolic regulation, bone formation, and immunity.