Macronutrient absorption characteristics in humans with short bowel syndrome and jejunocolonic anastomosis: starch is the most important carbohydrate substrate, although pectin supplementation may modestly enhance short chain fatty acid production and fluid absorption.

BACKGROUND: Diet may play an important role in the management of patients with short bowel syndrome who have colon in continuity. However, macronutrient absorption has not been well characterized, and the most appropriate dietary constituents have not been well defined. OBJECTIVE: To define carbohydrate absorption characteristics in patients with short bowel syndrome and determine the potential role of pectin as a dietary substrate. METHODS: The authors studied the effect of a custom pectin-based supplement in 6 subjects (3 male/3 female) aged 29-67 years with jejunocolonic anastomosis, 4 of whom required long-term parental nutrition. Small intestinal absorption capacity, macronutrient and fluid balance, gastrointestinal transit time, and energy consumption were measured. RESULTS: Data showed that 53% nitrogen, 50% fat, and 32% total energy were malabsorbed. In contrast, the majority (92%) of total carbohydrate was utilized. Fecal short-chain fatty acids (SCFAs) were increased, an indication of increased fermentation. Although only 4% of starch was recovered in stool, it is indicative of considerable starch malabsorption, thus providing the main carbohydrate substrate, for colonic bacterial fermentation. In contrast, nonstarch polysaccharide was a relatively minor fermentation substrate with only 49% utilized. Eighty percent of the pectin was fermented. Supplementation was associated with increased total SCFAs, acetate, and propionate excretion. There was a trend observed toward greater fluid absorption (-5.9% ± 54.4% to 26.9% ± 25.2%) following pectin supplementation. Nonsignificant increases in gastric emptying time and orocolonic transit time were observed. CONCLUSION: Despite malabsorption, starch is the primary carbohydrate substrate for colonic bacterial fermentation in patients with short bowel syndrome, although soluble fiber intake also enhances colonic SCFA production.

The role of comprehensive renal clinic in chronic kidney disease stabilization and management: The Northwestern experience.

In this article, we maintain that the management of patients with chronic kidney disease (CKD) is best provided in a clinic setting that integrates nephrologic expertise, patient education, and comprehensive supportive services. Our experience with a CKD clinic in an urban academic setting is described. As a way to assess and quantify the impact of our clinic on clinical outcomes, we have analyzed our results in terms of 2 variables: presence of permanent access at the time of dialysis initiation and impact on renal function as assessed by calculated glomerular filtration rate (GFR). The number of clinic visits was taken as an index of comprehensive renal care before dialysis initiation. Individuals who started dialysis with a functioning permanent access had been seen in our clinic more frequently than those seen less frequently (20 +/- 3.5 and 4.4 +/- 2.1 visits, respectively, P <.005). The impact on renal function was analyzed in a group of 80 unselected patients stratified into 3 stages based on the recently published National Kidney Foundation Disease Outcomes Quality Initiative (K/DOQI) guidelines: stage III (mean GFR 39 +/- 1.5 mL/min, n = 21), stage IV (mean GFR 21 +/- 0.6 mL/min, n = 46), and stage V (mean GFR 12 +/-.76 mL/min, n = 13). Provision of comprehensive renal care in conjunction with anemia management using weekly injections of erythropoietin subcutaneously resulted in stabilization of GFR in patients with stages IV and V over a period of 15 months of follow-up evaluation. In patients with stage III CKD, GFR decreased over the initial period of follow-up evaluation (first few months), and to a lesser extent by the end of follow-up evaluation (15 mo). Further studies are underway to discern the factor(s) underlying the overall clinic effect versus a beneficial effect of anemia correction on GFR. Our data suggests that stabilization of GFR is a goal that can be accomplished with comprehensive renal care provided in an organized clinic setting.