Nutrigenomics, also referred to as nutritional genomics, is a branch of science aimed at discovering how various nutrients interact with the genome and potentially alter genetic expression. One nutrient of particular interest is vitamin D, deficiency of which has been linked to diseases and conditions that develop in various organ and muscle systems throughout the entire body. Based on its extensive actions within the body, vitamin D supplementation is sometimes warranted. Caenorhabditis elegans is a good model organism for examining optimal levels of vitamin D supplementation in relation to vitamin D’s overall affect on aging since the DAF-12 nuclear hormone receptor in C. elegans is homologous to the Vitamin D Receptor (VDR) in humans. Lifespan assays were conducted to determine if vitamin D affects the lifespan of the worm. Results indicate that vitamin D significantly increases lifespan at a concentration of 1000 μg/ml. While it was hypothesized that vitamin D3’s interaction with a functional DAF-12 receptor may be required to mediate the effect of vitamin D on lifespan, results were not able to confirm this. Further studies should be done to test additional concentrations of vitamin D3 and to further test the role of DAF-12. McNair Scholar project. Faculty Advisors: Jennifer Schisa, Biology Department; Roschelle Heuberger, Department of Human Environmental Studies.