Digestion of “Resistant” Starch Sources in the Human Small Intestine

摘要

Background:Resistant starch sources,which are only partially digested in the small intestine,can be used to increase colonic avalialbiltiy of short chain fatty acids.Objective:To study the characteristics of the fermentiation of resistant starch,fist its small intestinal digestion has to be quantified.In our study,we performed this by comparing the metalbolic fate of highley digestible corn starch(DCS) ,Hylon VII and Novelose ,which are of corn origin and therefore naturally enriched in ^13C.Design:After administration of 40g starch or glucose to seven healthy volunteers,glucose and exogenous glucose concentrations in serum and 13CO2 excretion in breasth were analyzed for 6hr.Carbon-13 abundance of CO2 was analyzed by Isotope Ratio Mass Spectormtry(IRMS) and 13C abundance of glucose by Gas Chromatography/Combustion/IRMS.Results:comparing the area under the curve(2hr) or exgenous glucose concentration in serum(13C-glycemic index)after intake of starch or glucos.digestion percentages for DCS,hylon VII and Novelose were calcualted to be 82%±23%,44%±16%and 43%±15%,Comparing 6h cumulative percentage dose recovery in breath revealed that 119%±28% of DCS,55%±23%of Hylon VII and 50±26% of Novelose is digested in the small intestine.Conclusion:Theses data show that the exogenous glucose reponse in serum and the 13CO2 excretion in breath can be used to estimate smlall intestinal digestion of resistant starch,which amounts approximately 50%.