The Effect of Prebiotic Oligofructose Enriched Inulin Supplementation on Microbiota, Protein Metabolism and Gastrointestinal (GI) Symptoms in People Consuming High Protein Diets

Dietary protein levels are increasing worldwide and high protein consumption can be detrimental due to the generation of various toxic metabolites from gut bacterial fermentation. On the contrary, consumption of prebiotic carbohydrates allows specific microbiota changes, which may confer benefits upon host wellbeing and health. 

Volunteers were recruited from the Reading local community and 43 people completed the trial. Fasting blood, 24 hour urine and fresh faecal samples were collected at the University of Reading. Gastrointestinal symptoms and defaecation records were taken throughout the trial.

Bacteria were enumerated by fluorescence in situ hybridisation-flow cytometry. A significant increase in bifidobacteria was observed with the addition of prebiotic treatment (p<0.0001). Urine, blood plasma and faecal water metabolite changes were monitored by ¹H-NMR. There were lower concentrations of aromatic metabolites in urine and lower concentrations of lipids in blood plasma with prebiotic treatment, however, differences were not significant between the two interventions. Stool frequency was significantly (p<0.01) higher with prebiotic supplementation comparing to the placebo group and stool consistency had a trend towards softness as based on the Bristol scale (p=0.06). Mild symptoms of bloating and flatulence were reported with the prebiotic, however these were tolerable. Total bacteria and bifidobacteria changes during interventions were significantly correlated with stool frequency (p≤0.05). 

In conclusion, favourable bacterial and metabolic changes with ITF supplementation were found. ITF could exert health benefit improve health and wellbeing for high protein consumers, especially who also consume low fibre diet.