To your first question, that was done on PhD work in human cell lines and plants. What you observe is the production of the active metabolite (E.g. thiamine converted into thiamine pyrophosphate) or breakdown of the metabolite.

We are looking into that research right now with our advisors. This is definitely an ongoing research topic especially related to inflammatory diseases and cancer. We aren't making any of those claims yet since it's still hard to interpret these studies in human cell lines and small population in some of the clinical trials (E.g. the study that saw increased efficacy of a cancer drug with vitmin c). We are conducting further investigation and research with PIs that are doing this type of work. But for now, we do not have a consumer product that can measure epigenetic changes dynamically.