Efecto de la caseína en la absorción de d-xilosa medida mediante la prueba de H2 espirado / Effect of casein on d-xylose absorption measured by expired H2 test

ABSTRACT

Different experimental studies suggest that the presence of food in the alimentary tract, promote small intestinal absorption. The mechanism involved are not completely understood and might be related to motility changes or to humoral factors. Since studies have shown a decrease of small bowel motility after casein administration, the aim was to analyze the effect of this protein on small intestinal absorption and orocecal transit time. The hydrogen breath test was used to estimate d-xylose absorption. H2 production is dependent on the amount of this carbohydrate reaching the colon and therefore inversely proportional to d-xylose absorption. Six normal volunteers ingested 25 g d-xylose and 25 g de-xyllose + 30 g casein, and alveolar breath samples were obtained at 15 min intervals. Results: by adding casein to d-xylose solution a statistically significant decrease of maximal H2 concentration was observed from a mean of 40ñ11 ppm to a mean of 26ñ8 ppm. Similarly the area under the curve (which reflects the amount of xylose that was not absorbed) was also significantly decreased from a mean of 3281ñ1399 ppm to mean of 1394ñ700 ppm of H2. The orocecal transit time was significantly prolonged from 85.5ñ40 min to 112ñ38 min. Our results suggest that casein increased d-xylose absorption in normal subjects and that this effect might be related to a slower transit time