The Acute Effect of Inulin and Non-Inulin based Fibres on Gut Transit Time and Metabolic Biochemistry on Healthy Adults: A Pilot Study on Fibres

This is a pilot study aims to assess the acute effect of consuming inulin and non-inulin based dietary fibres. Inulin-based fibres including yacon, Jerusalem artichoke, globe artichoke, and Elephant garlic will be investigated alongside non-inulin-based fibres including apple, watermelon, orange and tomato. Throughout this study, both inulin and non-inulin fibres are referred as “test’ fibres. This study involves two clinic visits, each lasting 8 hours. The first visit is the screening visit, and the second visit is the study clinic visit. During both clinic visits volunteers will be provided with a standardise meal plan that provides approximately one-third of their daily caloric intake from carbohydrates, protein, and fat. Volunteers will need to attend both clinic visits fasted for 8 hours. During the fasting period, the volunteers may take sip of water or continue to take their regular medications. Diet: Volunteers may choose from either a vegetarian or meat-based standardised diet plan. For example , a standardised meat-based diet plan include toast with butter for breakfast, a chicken sandwich for lunch, roast chicken with potatoes for dinner, and crackers and cheddar cheese for snacks. In addition to the volunteers chosen standardize meal, volunteers will be provided up to three portions of the test fibres along with their breakfast. A portion of fibre is equivalent to the size of an average apple or a large globe artichoke. Volunteers may choose more than one test fibre but must have a gap of at least one week between each study clinic visit. Screening visit: The researcher will explain the study protocol and answer any questions that the volunteers may have about the study. On the day before the volunteers attend the screening visit, volunteers will be asked to avoid high-fibre diets. At the screening visit, the researcher will check the volunteer’s eligibility. The researcher will provide a standardise diet plan along with 10g of inulin at breakfast. A hydrogen breath test will be performed at baseline (i.e. before consuming 10g of inulin with breakfast) and then hourly for up to 8 hours. Individuals that show a sustained increase of exhaled hydrogen of > 20 ppm than baseline will be considered eligible to participate in the study. If the volunteers are eligible, they will be given the option to choose which test fibres they would like to participate in and will be invited to attend a study clinic visit, at least one week later. 24hr before the study clinic visit: The volunteers will start following the standardised diet plan provided at home. They will also be asked to complete a food diary that includes information about any non-study foods that they have consumed, the number of caffeinated and alcoholic beverages that they have consumed, their physical activity, and any intake of medication. Volunteers will also need to provide their age, and gender in this food diary. They can complete this diary in the comfort of their own home. Study Clinic Visit: At the clinic, the researchers will provide the standardise breakfast along with the volunteer’s test fibres. The researcher will perform the following assay and specimen collections at baseline (i.e. before consumption of fibres) and then hourly for 8 hours. 1. A serial urine collection at designated times, ideally including before consumption of the fibres of interest (U1), within 2hrs after breakfast (U2); before lunch (U3); within 2hrs after lunch (U4), and at the end of the 8 hr (U5). If volunteers do not need to urinate so frequently, they can collect a urine specimen every time they urinate and document the time. 2. An hourly hydrogen breath test. 3. An hourly blood collection via peripheral cannulation, with about 1 tablespoon (3mL) of blood taken every hour until the end of the study period. 4. A one-off collection of faeces samples (the size of a walnut). It is entirely up to the volunteer to decide if they would like to provide faeces samples on the day of the study clinic visit. If they provide a faeces sample, it will be analysed to evaluate the diversity of the gut bacteria. For female participants, urine and faeces collection should not be carried out during menstruation. The collected biological specimens will be analysed for various small molecules e.g. short-chain fatty acids, tricyclic cycles, amino acids, etc using both nuclear magnetic resonance spectroscopy and mass spectrometry-based metabolomics approaches. Adherence: Volunteers will consume the fibres on-site, and any uneaten fibres will be recorded by the researcher.