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

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

Cambios en los marcadores proteicos de repleción nutricional en pacientes desnutridos con nutrición enteral y su relación con los balances energético y nitrogenado / Changes in protein markers of nutritional repletion in undernurished patients with enteral nutrition and its relation with energetic and nitrogenous balance

Aim: to study the relation between tha changes in protein repletion indicators and calorie and nitrogen balance in undernurished patients receiving enteral nutrition. Patients and methods: fourteen patients (11 female, age range 55-85 years old) with an initial serum albumin below 3.5 g/dl or serum transferrin below 200 mg/dl, which receiving enteral nutrition, were studied. On days one and ten of nutritional support, indirect calorimetry, nitrogen balance and serum levels of albumin, transferrin, pre-albumin and total lymphocyte count were measured. Results: initial resting energy expenditure was 25.1ñ5 Kcal/kg/day (115.4ñ20 percent of that predicted by Harris Benedict equations) and urinary urea nitrogen 5.4ñ3.7 g/day. Initial and final nitrogen balances were 66.9ñ71 and 81.4ñ105.9 mg N/kg/day and mean energy balance throughout the study was +9.0ñ7.2 Kcal/kg/day. During the ten days of nutritional support, albumin improved significantly in 0.35ñ0.43 g/dl (15.2ñ19.8 percent). Transferrin, pre-albumin and total lymphocyte count did not change significantly. The changes in these last parameters did not correlate with nitrogen or calorie balance. Conclusions: probably other factors, besides nutritional balances, influence serum protein levels and these may not change despite an adequate nutritional repletion