CABALA Diet & Health Study

Study Overview
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Brief Summary
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During digestion of fatty foods, the liver produces a substance called bile which helps with the absorption of fat in the gut (small intestine). Some research studies have shown that friendly bacteria that live in our gut can change the makeup of bile (referred to as bile acids) leading to a lowering of blood cholesterol levels, an important risk factor for developing heart disease. This finding has been found in people who consume diets high in dietary fibers and probiotics that enhance the growth of friendly gut bacteria, and also plant rich foods high in polyphenols (such as apples). At present, very little is known about how the makeup of bile acids can regulate blood cholesterol levels and if their measurement in blood, urine or stool samples can be used as an indicator of human health. The aim of this study is to explore how consumption of foods which enhance the growth of friendly gut bacteria (such as probiotics, prebiotics, and plant rich foods high in polyphenols) can change the makeup of bile acids after 8 weeks. Changes in the bile acids measured in blood and stool samples will then be related to markers of health, such as blood cholesterol, glucose, insulin, vascular health and inflammatory markers.

Official Title
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CirculAting Bile Acids as Biomarkers of Metabolic Health - Linking microbiotA, Diet and Health

Conditions
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Healthy

Intervention / Treatment
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* Other: Apple
* Other: Oats
* Dietary Supplement: Lactobacillus reuteri NCIMB 30242
* Other: Cornflakes


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women Aged 25-70 years BMI: 23-32 kg/m2 Fasting glucose < 7 mmol/l Total cholesterol < 7.5 mmol/L Triglycerides < 2.3 mmol/L Habitual breakfast consumers Weight stable in the last three months Exclusion Criteria: Smoker Diabetes Endocrine disease Cardiovascular disease diagnosis Gastrointestinal diseases Pancreatic, hepatic or renal diseases Medications that could influence study outcomes (e.g. lipid lowering medications, anti-depressants, anticoagulants) Antibiotic use within the last three months Food allergies (e.g. gluten, dairy, apples) and intolerances (e.g. lactose) Alcohol or drug abuse (Drink more than 14 units of alcohol per week) Anemia (men:haemoglobin<130g/ L and women <120 g/L Planning or currently on a weight reducing program Pregnancy, planned pregnancy in the next year or lactating Irregular menstrual cycle Planning or currently on a weight reducing program Currently taking part or participation in other research studies within the last three months Recent blood donation or unwilling to refrain from donating blood during the study Regular consumption of probiotic or prebiotic food supplements or fiber based laxatives and unwilling stop consuming these for the duration of the study

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 70 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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Apple/ Polyphenol<br>Participants will be asked to consume 2 Renetta Canada apples (with skin) and 2 placebo capsules every day for 8 weeks. | Other: Apple<br>* 2 Renetta Canada apples and 2 placebo capsules/ day<br>* Other names: Polyphenol;|
| Experimental: Oats / Prebiotic<br>Participants will be asked to consume 40g jumbo rolled oats with semi-skimmed milk and 2 placebo capsules every day for 8 weeks. | Other: Oats<br>* 40g jumbo rolled oats with semi-skimmed milk and 2 placebo capsules / day<br>* Other names: Prebiotic;|
| Experimental: Lactobacillus reuteri NCIMB 30242 / Probiotic<br>Participants will be asked to consume 2 probiotic capsules and 40g cornflakes with semi-skimmed milk every day for 8 weeks. | Dietary Supplement: Lactobacillus reuteri NCIMB 30242<br>* 2 probiotic capsules and 40g cornflakes with semi-skimmed milk / day.<br>* Other names: Probiotic;|
| Placebo Comparator: Placebo / cornflakes<br>Participants will be asked to consume 40g cornflakes with semi-skimmed milk and 2 placebo capsules every day for 8 weeks. | Other: Cornflakes<br>* 40g cornflakes with semi-skimmed milk and 2 placebo capsules/ day.<br>* Other names: Placebo;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Circulating bile acids | Plasma bile acid profile | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood lipid profile | total, low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol, triacylglycerol (TAG) and non-esterified fatty acids (NEFA) | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Glucose response | Fasting and postprandial blood glucose concentrations | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Insulin response | Fasting and postprandial blood insulin concentrations | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| C-peptide | Fasting and postprandial blood C-peptide concentrations | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Inflammatory markers | Fasting blood concentrations of C-reactive protein (CRP), IL-18, IL-1β and tumour necrosis factor alpha (TNF-α) | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Gut hormones | Fasting and postprandial concentrations of peptide YY, Glucagon-Like Peptide 1, Fibroblast growth factor 19 | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Metabolomics | Profile of metabolites in the blood (fasting and postprandial) | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Nitric Oxide | Fasting and postprandial concentrations of nitric oxide | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Cell-adhesion molecules | Fasting and postprandial concentrations of ICAM and VCAM | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Short-chain fatty acids | Fasting and postprandial circulating short-chain fatty acids concentrations and fecal short-chain fatty acid concentrations | Chronic and acute effects: Fasting and 6-hour postprandial response and faecal sample at both baseline and week 8 | 
| LDL receptor expression | LDL receptor expression in peripheral blood mononuclear cells | This will be measured at baseline | 
| Genotyping of bile acid receptor gene | Genotyping of single-nucleotide polymorphisms (SNPs) in the FXR-encoding gene NR1H4 | This will be measured at baseline | 
| Platelets | Platelets will be collected for in-vitro studies | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Gut microbiota | Next-generation sequencing of gut bacteria and enumeration of selected bacteria using FISH (fecal samples) | At baseline and week 8 | 
| Bile acid excretion | Fecal bile acid concentrations | At baseline and week 8 | 
| Energy excretion | Bomb calorimetry of fecal samples | At baseline and week 8 | 
| Urine metabolites | Markers of intervention foods/ supplements in urine (24h urine collection) | At baseline and week 8 | 
| Blood pressure and heart rate | Ambulatory blood pressure and heart rate | Chronic and acute effects: Fasting and 6-hour postprandial response at both baseline and week 8 | 
| Body composition | Body composition measured using bio-impedance | At baseline and week 8 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bile acids, Lipid metabolism, Cholesterol, Probiotics, Polyphenols, Prebiotics, Gut bacteria, Gut microbiota