Enteral nutrition as primary therapy in short bowel syndrome.

The spectacular success of parenteral nutrition in supporting patients during small intestinal adaptation after massive resection, tends to obscure the prolonged periods often needed for such adaptation to take place. After neonatal small intestinal resection for example, it may take more than five years before adaptation is complete. There is therefore a strong argument for examining ways in which adaptation can be facilitated, in particular, by the addition of novel substrates to enteral feeds. Pectin is completely fermented by colonic bacteria to short chain fatty acids. In the rat, addition of pectin to enteral feeds led to a more rapid adaptive response in both the small and large intestine after massive small intestinal resection, although faecal nitrogen losses were increased. In a similar rat model, the provision of 40% of non-protein energy as short chain triglycerides facilitated the adaptive response in the jejunum, colon, and pancreas. The importance of glutamine as a metabolic substrate for the small intestine makes it another potential candidate and some, but not all animal studies, have suggested a therapeutic effect: increasing the glutamine content of feeds to 25% of total amino acids produced enhanced jejunal and ileal hyperplasia, even on a hypocaloric feed, and an improved overall weight gain. Studies in humans are very limited, but such promising results in the experimental animal suggest that this is probably a fruitful area for further study.