Abstract
Background
Treatment with exclusive enteral nutrition (EEN) offers a nutritional therapy paradigm in Crohn’s disease, with the extensive modulation of gut microbiome being its proposed mechanism of action (1). Recent studies propose variable clinical efficacy for 85% EN (Cheat EN/CEN), 50% EN (Partial EN/PEN) and 20% EN (maintenance EN/MEN), and a dose-dependent effect of EN use in CD (2–5). Therefore, this study aims to investigate the dose-dependent effect of 100%, 85%, 50%, and 20% EN on faecal microbial metabolites; and to investigate if this effect can be used as a compliance marker for EEN.
Methods
Healthy adults followed EEN, CEN, PEN or MEN diet for 7 days. Fresh faecal samples were collected before and after each dietary intervention Dietary assessment was performed throughout the intervention using estimated weight food diaries. Faecal pH, water content, Bristol Stool Chart Score, short-chain fatty acids and hydrogen sulphide were measured.
Results
A total of 122 faecal samples were collected from 61 subjects. The Mean(SEM) EN intake for the four groups was EEN: 100(0), CEN: 85.6(0.5), PEN: 50.1(0.4), MEN: 19.9(0.2) % of total energy intake. The baseline levels of all faecal sample measures were no different between the four groups. Faecal water content, propionic acid and Bristol Stool Chart Score significantly decreased only during EEN (all p≤0.03). Faecal pH significantly increased during EEN, CEN and PEN (all p < 0.001), but not during MEN (p = 0.728). Faecal pH post-intervention was highest for EEN, followed by CEN and PEN [Mean(SEM), EEN: 8.2(0.1); CEN: 7.8(0.2); PEN: 7.3(0.1), all pairwise p ≤ 0.002]. The faecal concentration of hydrogen sulphide, acetic and butyric acid significantly decreased following both EEN and CEN groups (all p ≤ 0.009). The concentration of acetic acid post-EEN was significantly lower than the concentration post CEN [Mean(SEM), EEN: 173(10); CEN: 261(24) μmol/g, p = 0.001]. Hydrogen sulphide and butyric acid concentrations post EEN and post CEN were unchanged (p = 0.337, p = 0.141).
Conclusion
EEN extensively modulates faecal microbial metabolites and CEN induces similar effects. PEN induces variable effects and further analysis should investigate if variation in responses reflects differences in the non-EN food intake of the participants (50%). MEN had no effect on faecal microbial metabolites. Further analysis including high-throughput deep sequencing techniques will provide additional information about the dose-dependent effect of EN regimen on gut microbiome composition.
References
1. Quince et al., Am J Gastroenterol, 110:1718–1729.
2. Logan et al., Aliment Pharmacol Ther, 2019;50:664–674.
3. Gupta et al., IBD, 2013;19:1374–1378.
4. Duncan et al., BMC Gastroenterol, 2014;14:50.
5. Lee et al., IBD, 2015;21:1786–1793.
Understanding the Role of the Gut Microbiome and Microbial Metabolites in Obesity and Obesity-Associated Metabolic Disorders: Current Evidence and Perspectives