Optimising gastrointestinal hormone and satiety responses through targeted delivery of metabolites to the human gut
Investigating gut hormone and satiety responses
15 healthy volunteers will attend a screening and a 3-day inpatient visit. During the main visit, two nasoenteric tubes will be inserted through nostrils into the ileum (day 1) and duodenum (day 2). Tube placements will be performed by a consultant radiologist. The locations of tubes will be verified by fluoroscopy. Once tubes are in place, participants will receive one of the following intervention/control treatments on day 2 and day 3 in a randomised order; randomisation will be performed using the 'sealed envelope' website by an independent researcher (i.e., not linked to the study): • Intervention arm: Participants will consume an oral drink through a straw within 5 minutes (T0–5 min). This is composed of maltose and glucose, which are simple sugars. Then Infuscate D (a mixture of amino acids, the building bricks of proteins) will be infused to the duodenum from T30 to T120 minutes, and Infusate L (composed of simple sugars maltose, glucose and amino acids) to the ileum from 60 to 180 minutes. The drinks and infusates are composed of nutrients from food and are given in amounts that will reproduce the concentrations seen in the gut following food in our precious study. • Control arm: Participants will consume an equal volume of a 0.9% saline solution as the drink. Then 0.9% saline solution will be infused into the duodenum and ileum at the corresponding rates and timeframes to match the intervention group. Blood samples will be taken during the 0-180min period to measure appetite-related hormones, metabolite changes and glycaemic outcomes; Subjective appetite scores will be recorded; Urine samples will be collected to measure metabolite levels. After the infusion interventions, a pasta meal will be provided to measure food intake.
1. Male or female 2. Age between 18-65 years (inclusive) 3. Body mass index (BMI) of 18-30 kg/m2 4. Willingness and ability to give written informed consent and willingness and ability to understand, to participate and to comply with the study requirements
1. Gastrointestinal disease e.g. inflammatory bowel disease or irritable bowel syndrome 2. Abnormal ECG 3. Screening blood results outside of normal reference values 4. Weight change of > = 5kg in the preceding 2 months 5. Current smokers 6. History of substance abuse and/or excess alcohol intake 7. Pregnancy 8. Diabetes 9. Cardiovascular disease 10. Cancer 11. Kidney disease 12. Liver disease 13. Pancreatitis 14. Started new medication within the last 3 months likely to interfere with energy metabolism, appetite regulation and hormonal balance, including: anti-inflammatory drugs or steroids, antibiotics, androgens, phenytoin, erythromycin or thyroid hormones. 15. Participation in a research study in the 12-week period prior to entering this study. 16. Any blood donation within the 12-week period prior to entering this study 17. Previous surgery on the bones inside the nose, or nasal airway obstruction Any participants with the above conditions would already have an altered pattern of hormones and inflammatory molecules because of their disease process and would therefore give us confounding or misleading results.