Abstract

Background—Medium chain C8–C10 triglycerides (MCTs) improve fat absorption in short bowel patients. Effects on overall energy absorption remain unknown.

Aims—To determine whether MCTs and medium chain fatty acids (MCFAs) are absorbed in the colon like the short chain fatty acids (SCFAs) or are lost in faeces similarly to long chain fatty acids (LCFAs).

Methods—Nine small bowel resected patients without and 10 with a colon in continuity excreted 2–6 MJ/day and were randomised and crossed over between two high fat diets (10 MJ/day, 50% as fat), based on either long chain triglycerides (LCT) alone or equal quantities of LCT and MCT.

Results—Patients with a colon absorbed C8–C10 fatty acids considerably better than patients without a colon at similar and extreme levels of LCFA malabsorption; the colonic impact on absorption of C14–18 fatty acids was negligible. MCT redoubled fat (MCT+LCT) absorption from 23% to 58% in patients with a colon, and increased overall bomb calorimetric energy absorption from 46% to 58%. The increase in fat absorption from 37% to 46% in patients without a colon did not improve overall energy absorption because malabsorption of carbohydrate and protein increased.

Conclusion—In small bowel resected patients, the colon seems to serve as a digestive organ for medium chain fat, probably absorbed as MCFAs, perhaps because like the SCFAs, they are water soluble. Only patients with a colon gained from MCT treatment.