Importance of colonic support for energy absorption as small-bowel failure proceeds

Abstract

Digestive processes in the human colon are affected by the bacterial fermentation of malabsorbed carbohydrates and protein to short-chain fatty acids, which are absorbed and supply energy. Energy absorption was measured by assessing fecal bomb calorimetry in 148 patients with extremely different small-bowel lengths. Colectomy increased fecal loss of energy by 0.8 MJ/d and carbohydrate excretion fivefold in patients with a small-bowel length between normal and 150-200 cm. Patients with 100-150 cm small bowel, with and without a colon, excreted 1.3 +/- 0.3 and 4.7 +/- 0.5 MJ/d, respectively (P = 0.002), a difference of 3.4 MJ/d. Patients with < 100 cm small bowel excreted 3.1 +/- 0.4 and 8.0 +/- 1.3 MJ/d, respectively (P = 0.03), a difference of 4.9 MJ/d. Similar and highly significant differences were calculated by linear-regression analysis. Considerably less energy was excreted as carbohydrate than as fat in patients with preserved colonic function, probably because fermentation removed carbohydrate as absorbed short-chain fatty acids, whereas a comparable amount of energy was lost as carbohydrate and fat in patients without colonic function. The correlation between malabsorbed energy and small-bowel length was poor (r = -0.41) but increased when data for patients with and without a colon were separated (r = -0.56 and r = -0.58, respectively). Small-bowel length, however, was still an inaccurate measure of intestinal failure to absorb nutrient energy. In conclusion, colonic digestion may support energy supply with up to approximately 4.2 MJ/d as small-bowel failure proceeds, but it is of minor importance in patients with a small-bowel length > 200 cm or malabsorption < 2.1 MJ/d.

Nutrient intake from habitual oral diet in patients with severe short bowel syndrome living in the southeastern United States

“…In patients with residual in-continuity colon, diets high in complex carbohydrates may help to savage extra calories (≈ 800-1100 kcal/day in some studies) derived from the SCFA acetate, butyrate, proprionate that are produced by bacterial fermentation of malabsorbed dietary carbohydrate and fiber (24)(25)(26)38). High-fat diets in these patients increase losses of fluid and nitrogen, and result in higher fecal loss of energy (22,24).…”

“…SBS patients without residual colon do not generally respond to a fat-restricted diet with decreased diarrhea volume; a more liberal use of dietary fat is important in these individual for adequate enteral caloric intake during PN weaning (7)(8)(21)(22). In patients with jejuno-or ileostomies high carbohydrate intake, especially simple sugars, worsen stomal effluents, whereas high-fat diets may increase ostomy fat loss but improve total energy absorption (21,25). Sipping of near-isotonic oral re-hydration fluids with a high content of sodium is essential in patients with jejunostomies, whereas patients with colon and ileostomies may tolerate hypotonic solutions as and additional sodium chloride added to food (2,8).…”

“…Initial small studies in patients with SBS found no difference in intestinal losses and nutrient absorption with modifications in diet composition (22,23). Recent studies with larger groups of patients clearly show that patients with residual colon require a different diet composition than those without colon, in that these individuals benefit from diets generally lower in fat content and high in complex carbohydrates via bacterial generation of short chain fatty acids (SCFA), whereas those with ileo-or jejunostomies do not generally respond to fat restriction (7)(8)24,25,26,27,28,29).…”

Severe Intestinal Failure in a Chagas’s Disease Patient After Total Colectomy Plus Partial Ileectomy

“…Indeed, patients undergoing small bowel resection plus total colectomy could present considerable increases in the loss of energy and nutrients through the feces 7 .…”

“…These changes caused episodes of partial or complete intestinal obstruction and volvulus of the stomach, resulting in periods of fasting and worsening protein-energy malnutrition. In addition, patients without an intact colon exhibit impaired water absorption and lower stimulus for hyperplasia of the small intestine 7 .…”