Snack Foods and Their Impact on Gastrointestinal Microbiology, Function and Symptoms

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the impact of replacing usual snacks with alternative snack foods on gut health in a population of habitual snackers with low fibre intake.

Detailed Description
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Diet is a crucial target for the improvement of human health. In the modern world, diets are diverse and diet related diseases are becoming more and more common. In particular, it is becoming increasingly apparent that the bacteria that live in the gut are strongly linked to both diet and health. Bacteria in the gut can be beneficial or harmful, and the health of the gut relies on the beneficial bacteria outnumbering the harmful ones. Diet has a great impact on the bacterial composition of the gut. In turn, the gut bacteria play diverse roles in human health, influencing not only the gut but also the health of the immune system, heart and brain. Therefore, optimising the composition of the gut bacterial is vital to human health and wellbeing. It has been shown that snacks between meals contributes 420 - 480 calories per day, almost a quarter of the recommended intake. Therefore, snack choices are an area of diet and lifestyle that have the potential to influence diet and in turn the health of our gut and gut bacteria. We would like to assess the effect of replacing usual snacks with alternative snack foods that we believe have benefits for gut health. The primary aim of the study is to investigate whether the replacement of usual snacks has an effect on gut bacterial composition, specifically the abundance of Bifidobacteria. Secondary aims include the effect of the intervention snacks on additional measures of gut health such as gut transit time, the frequency and consistency of bowel movements and gut symptoms e.g. heartburn, nausea, belching etc. The effect of snack foods on metabolites in the blood (e.g. glucose, insulin, lipids) will also be determined. Finally the impact of snack replacement on mood and quality of life will be assessed.

Official Title
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Snack Foods and Their Impact on Gastrointestinal Physiology, Luminal Microbiology and Gastrointestinal Symptoms

Conditions
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Human Microbiome, Eating Behavior

Intervention / Treatment
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* Dietary Supplement: Intervention snack 1
* Dietary Supplement: Intervention snack 2
* Dietary Supplement: Control snack


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female Aged between 18-45 years Body mass index (BMI) of 18.5 - 29.9 kg/m2 Regular consumption of snacks (≥2 per day, excluding fruit and nut snacks) Low fibre intake (<22 g/d) Willing to follow the protocol and provide consent Exclusion Criteria: Allergy or intolerance to snack ingredients (assessed at screening) Dislike of study snacks Regular consumption of intervention foods as snacks (twice a day in last month) Diabetes Major active psychiatric conditions (e.g. schizophrenia) or current eating disorder Active treatment for cancer in the last year Severe renal, cardiac or pulmonary disease or any other chronic medical condition Severe oesophagitis, gastritis or duodenitis Active diverticulitis or intestinal/colonic strictures Crohns disease or Ulcerative colitis Abdominal surgery (except appendicectomy or cholecystectomy) Irritable bowel syndrome Functional constipation Functional diarrhoea Antibiotics (past 4 weeks) Ongoing therapy with drugs affecting gastrointestinal motility Use of medical devices (Pacemakers, infusion pumps, insulin pumps) Women who are pregnant/lactating/planning pregnancy Recent/ongoing consumption of probiotics/prebiotics (past 4 weeks) Ongoing abuse of alcohol/drugs/other medication Very high physical activity levels Unexplained/unintentional weight loss in the past 6 months

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Intervention snack 1<br>Snack food believed to selectively promote the growth of beneficial bacterial strains in the human colon. | Dietary Supplement: Intervention snack 1<br>* To be eaten instead of regular snacks twice a day for 4 weeks.<br>|
| Active Comparator: Intervention snack 2<br>Snack food believed to selectively promote the growth of beneficial bacterial strains in the human colon. | Dietary Supplement: Intervention snack 2<br>* To be eaten instead of regular snacks twice a day for 4 weeks.<br>|
| Placebo Comparator: Control snack<br>Control snack food reflecting the macro-nutrient profile of a typical UK snack. | Dietary Supplement: Control snack<br>* To be eaten instead of regular snacks twice a day for 4 weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Faecal bifidobacteria | Measured by 16S community profiling (Illumina Miseq) of bacterial genomic DNA isolated from participant stool samples | Baseline | 
| Faecal bifidobacteria | Measured by 16S community profiling (Illumina Miseq) of bacterial genomic DNA isolated from participant stool samples | Day 28 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Whole gut transit time | Measured using the SmartPill wireless motility capsule | Baseline | 
| Whole gut transit time | Measured using the SmartPill wireless motility capsule | Day 28 | 
| Regional gut transit time | Measured using the SmartPill wireless motility capsule | Baseline | 
| Regional gut transit time | Measured using the SmartPill wireless motility capsule | Day 28 | 
| Regional gut pH | Measured using the SmartPill wireless motility capsule | Baseline | 
| Regional gut pH | Measured using the SmartPill wireless motility capsule | Day 28 | 
| Faecal gut microbiota (alpha- and beta-diversity) | Measured by 16S community profiling (Illumina Miseq) of bacterial genomic DNA isolated from participant stool samples | Baseline | 
| Faecal gut microbiota (alpha- and beta-diversity) | Measured by 16S community profiling (Illumina Miseq) of bacterial genomic DNA isolated from participant stool samples | Day 28 | 
| Faecal short-chain fatty acids (SCFA) | Measured by gas liquid chromatography of stool sample | Baseline | 
| Faecal short-chain fatty acids (SCFA) | Measured by gas liquid chromatography of stool sample | Day 28 | 
| Faecal water | Measured by lyophilization of stool sample | Baseline | 
| Faecal water | Measured by lyophilization of stool sample | Day 28 | 
| Faecal volatile organic compounds | Measured by gas-chromatography mass-spectrometry of stool samples | Baseline | 
| Faecal volatile organic compounds | Measured by gas-chromatography mass-spectrometry of stool samples | Day 28 | 
| Gut symptoms | Gastrointestinal symptoms rating scale (7-day; questionnaire) | Week 0 | 
| Gut symptoms | Gastrointestinal symptoms rating scale (7-day; questionnaire) | week 4 | 
| Stool frequency | Bristol stool form scale (7-day; questionnaire) | Week 0 | 
| Stool frequency | Bristol stool form scale(7-day; questionnaire) | Week 4 | 
| Dietary intake | 7-day food diary | Week 0 | 
| Dietary intake | 7-day food diary | Week 4 | 
| Quality of life | SF-36 questionnaire | Baseline | 
| Quality of life | SF-36 questionnaire | Day 28 | 
| Mood | Hospital anxiety and depression scale | Baseline | 
| Mood | Hospital anxiety and depression scale | Day 28 | 
| Physical activity | Recent physical activity questionnaire | Baseline | 
| Physical activity | Recent physical activity questionnaire | Day 28 | 
| Dietary metabolites (various) | Measured in blood sample | Baseline | 
| Dietary metabolites (various) | Measured in blood sample | Day 28 | 
| Particle size of masticated snack foods | Mechanical sieving and laser diffraction of masticated snack foods | Day 28 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gut Microbiota, Microbiome, Gut Health, Snack