The vitamin rheostat: A unified model of epigenetic feedback in vitamin homeostasis.

Recent evidence implicates epigenetic mechanisms in vitamin metabolism, yet most studies remain focused on individual vitamins. In this mini-review, we extend beyond single-vitamin paradigms to propose the Vitamin Rheostat: a unifying model in which vitamins influence regulatory signaling networks that shape their own uptake, utilization, and degradation. By integrating fat-soluble vitamins (nuclear receptor-mediated signaling) and water-soluble vitamins (methyl-donor and enzymatic cofactor systems), this model provides a predictive and experimentally testable framework that may help explain inter-individual variability in response to vitamin intake. It repositions epigenetics as an active mediator in vitamin homeostasis and supports the development of chromatin-informed approaches to precision nutrition.