Abstract
Scope: Research reports suggest that vitamin D affects glucose and insulin metabolism; however, the exact mechanisms are unclear. ^2^H NMR analysis of monoacetone glucose (MAG) after tracer administration provides a nonβinvasive method of profiling hepatic glucose metabolism. This study examined the effects of supplementation with vitamin D~3~ on contribution of glycogenolysis to glucose production.
Methods and results: Tracer administration and biofluid collections were performed with eight healthy females before and following a 4βwk vitamin D~3~ administration period. Following an overnight fast subjects ingested deuterated water and acetaminophen. Full void urine samples were collected after 4βh. ^2^H NMR spectra of urinary monoacetone glucose were acquired to determine the contribution of glycogenolysis to glucose production. The mean contribution of glycogenolysis to glucose production was 60Β±13%. Supplementation with vitamin D~3~ had no effect on hepatic glucose production. Regression analysis revealed a significant relationship between carbohydrate intake and the contribution of glycogenolysis (Ξ²=0.914, p=0.004).
Conclusion: In conclusion, we saw no changes in the percentage contribution of glycogenolysis following supplementation with vitamin D~3~. The reproducibility of our results and the nonβinvasive nature of the method highlight the potential for this method in assessing mechanistic modes of action in future nutritional interventions.