Plain English Summary
Background and study aims
High fibre diets are known to be related to a number of health benefits and have been widely advertised (in breakfast cereals, for example) as a way of helping people to lose weight. We are currently researching short chain fatty acids, one of the breakdown products of fibre, which may be responsible for the beneficial effects of fibre. Our recent work suggests that one specific short chain fatty acid, propionate, is associated with a reduction in feelings of hunger. Different dietary fibres produce different amounts of propionate. It is currently unknown which dietary fibres produce the largest amounts of propionate and whether they affect appetite (i.e. how hungry or full you feel). The aim of this study is to find out the effects of a range of dietary fibres on propionate levels and appetite. This may be important in terms of controlling body weight and therefore preventing obesity.
Who can participate?
This study will be carried out in healthy men and women, aged 18-65 years old, who are either normal weight or overweight.
What does the study involve?
There are two parts to this study. Part A and B both consist of four separate study visits. In Part A, on the study days participants will receive a standard breakfast containing 10g of one of four food supplements and two non-radioactive tracer molecules, which will be used in order to track the digestive process. A standard snack and meal will also be provided. Participants will complete questionnaires to measure appetite, and breath and blood samples will be collected. In Part B, participants will be instructed to consume one of the four dietary supplements from Part A in an increased dose for 7 days before each of the four study visits. On study days, participants will consume a standard breakfast, which will contain 10 g of the same dietary supplement that they have been taking. A snack and buffet meal will also be provided. The following measurements will be collected: amount of propionate in blood, appetite ratings using questionnaires, food intake at a buffet meal (where participants are instructed to eat until they feel comfortably full) and breath hydrogen samples.
What are the possible benefits and risks of participating?
Volunteers will not benefit directly from this study but the results may help doctors in the future treat patients with obesity. Some of the procedures in this study, such as the recording of your weight, height and blood pressure, and the collection of breath samples, present no risk. Taking blood samples can cause mild discomfort when the needle is inserted, and possible bruising and infection in that area. These procedures will only be carried out by experienced healthcare professionals under germ-free conditions in order to minimise such risks. As with any high fibre diet, volunteers may experience tummy bloating and discomfort. There is also a small chance that volunteers may experience episodes of diarrhoea during the study. In order to minimise the risk of this happening, in Part B the total dose of dietary supplement being consumed will be increased slowly over the course of the 7 days before each study visit. Volunteers may also find the taste of the dietary supplements unpleasant and so will be advised on the best way to add it into your diet. The addition of the dietary supplement to their daily routine will be an inconvenience and will require a change in lifestyle. To minimise inconvenience, all supplements will be provided in ready-to-use sachets.
Where is the study run from?
Hammersmith Hospital (UK).
When is the study starting and how long is it expected to run for?
The study will start in August 2014 and will run until July 2015.
Who is funding the study?
Medical Research Council (MRC) (UK).
Who is the main contact?
Miss Claire Byrne
Miss Claire Byrne
Du Cane Road
The effect of short-term dietary supplementation of fermentable carbohydrates on propionate production and appetite measures: a pilot study
The aim of this study is to investigate whether short-term dietary supplementation of fermentable carbohydrate (FC) increases plasma propionate concentrations and suppresses appetite in humans.
NRES Committee London Harrow, 16/06/2014, ref. 14/LO/0704
Randomised single-blind cross-over feeding study
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Topic: Primary Care; Subtopic: Not Assigned; Disease: All Diseases
This will be a study comparing the effects of B-glucan (fermentable, soluble and viscous) on appetite and plasma propionate concentrations, with inulin (fermentable, soluble and non-viscous), cellulose (non-fermentable, insoluble and non-viscous) and methyl cellulose (non-fermentable, soluble and viscous). This study will involve four separate 7-day feeding periods followed by study days, with a 2-week wash-out period between study visits. This study will be preceded by a protocol optimisation study, which will involve four separate study visits. Inulin will be used as a positive control (as we know it is fermented in the colon) and cellulose as a negative control (as we know it does not ferment significantly in the colon) in both studies. The addition of methyl cellulose (a non-fermentable, soluble and viscous product) as a fourth leg to both studies will allow for the assessment of the effect of viscosity on appetite measures. Two studies are proposed: an optimisation study to assess the effect of FCs on gut transit time and therefore optimise sampling regimens, and a feeding study to assess the effect of FCs on appetite.
In the Optimisation Study, participants will consume 10 g of one of the four dietary supplements on each of the four study days according to their randomisation pattern.
In the Feeding Study, participants will consume a different dietary supplement in a stepped dose for 7 days prior to each one of the four study visits. Participants will consume 10 g of the appropriate dietary supplement on day 1, two 10 g servings on days 2-3 (total daily dose 20 g), and three 10 g servings on days 4-7 (total daily dose 30 g). On study days, volunteers will receive 10 g of the appropriate dietary supplement with their breakfast. The maximum dose used in this study is based on previous work carried out by our research group.
Randomisation will be conducted by sealed envelopes once the participants have successfully passed the health screening. The participants will be blinded as to the type of supplement they are taking.
Primary outcome measures
Appetite; Timepoint(s): measures every 30 minutes over the study period
Secondary outcome measures
1. 13CO2 enriched breath hydrogen; Timepoint(s): measure every 30 minutes over the time period
2. Plasma propionate; Timepoint(s): measured every 30 minutes over the study period
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Body Mass Index (BMI) 20-35 kg/m2
2. Age 18-65
Target number of participants
Planned Sample Size: 20; UK Sample Size: 20
Participant exclusion criteria
Any gastrointestinal disease
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Du Cane Road
Medical Research Council (MRC) (UK) - Clinical Trials Unit (CTU)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting