This study supplements two earlier in print exploratory studies investigating the absorption of folate across the colon after an infusion during colonoscopy and a pre-trial with the purpose of determining dissolution characteristics of two placebo caplet formulations. Using a dual route oral/intravenous, folate (pharmaceutical name Calcium Leucovorin), labeled with a stable isotope will be used to quantitatively measure total folate levels, as well as the uptake of (13C) labeled folate. A pH dependent caplet targeted to the colon and fluoroscopy will determine dissolution characteristics. Labeled and unlabelled folate in blood and urine samples will be used to quantitatively measure the uptake of folate. This will further our understanding of the kinetics (caplet transit times), colonic folate absorption (metabolism) and impact on folate status (bioavailability) in healthy adults.