Health Effects of Different Types of Bread

Study Overview
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Brief Summary
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Dietary fiber is well known to have health promoting effects, including reduced blood glucose and cholesterol levels. Bread is the most important source of dietary fiber in the Norwegian diet. Production of bread has changed from the traditionally use of sourdough, to yeast (Saccharomyces cerevisiae) as the dominating leavening agent in modern industrial production. Sourdough naturally contains bacteria, and through the fermentation process these bacteria release several components that are not found in modern bread using yeast. It has been shown that sourdough may have positive health effects, including on blood glucose regulation. The aim of the project is to investigate if intake of sourdough may give positive health effects compared to beard with yeast.

Detailed Description
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The investigators aim to include approximately 20 participants in this randomized controlled double-blind cross-over study lasting for 5 weeks. All participants will be given bread baked with yeast for a 2 weeks run-in period. The participants will then be randomly assigned to either 1 week intervention with bread baked with yeast or sourdough, before a 1 week wash-out period with yeast bread. During the last 1 week intervention period the participants starting with bread baked with yeast will be given sourdough and vice versa. Questionnaires (GSRS-IBS, BSC, FFQ), blood samples, and feces samples will be collected before and after the intervention periods.

Official Title
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Health Effects and Consumer Aspects of Different Types of Bread

Conditions
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IBS

Intervention / Treatment
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* Other: Intervention group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy adults who restrict their intake of bread due to stomach ache. Exclusion Criteria: Chronic metabolic diseases, such as diabetes type 1 or 2, cardiovascular diseases and cancer last 6 months Gut diseases, including Chron's disease, ulcers colitis Food allergies or intolerance Pregnant and/or lactating Smokers BMI <18,5 and >27 kg/m2 Planed weight reduction and/or ± 5% weight change last 3 months Blood donor last 2 months and during the study period Not willing to quit taking dietary supplements, including probiotics, cod liver oil etc., 4 weeks prior to study start and during the study Use of antibiotics <3 months prior to study start and during the study Alcohol intake >40 g/day Hormone treatment (except contraceptives)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Wholegrain bread with yeast<br>The control group will be given min. 5 slices of bread baked with yeast per day. | Other: Intervention group<br>* intervention group: bread with sourdough control group: bread with yeast<br>|
| Experimental: Wholegrain bread with sourdough<br>The experimental group will be given min. 5 slices of bread baked with sourdough per day. | Other: Intervention group<br>* intervention group: bread with sourdough control group: bread with yeast<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gastrointestinal Symptom Rating Scale-irritable bowl syndrome (GSRS-IBS) | GSRS-IBS analysis after intervention with bread baked with yeast versus sourdough with the following response scale: 1 (no discomfort at all) to 7 (very severe discomfort) | 5 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bristol stool chart (BSC) | BSC analyses after intervention with bread baked with yeast versus sourdough with a scale from 1 (separate hard lumps, like nuts) to 7 (watery, no solid pieces) | 5 weeks | 
| Blood C-peptide, total cholesterol, triglycerides, fatty acid profile, and short chain fatty acids | Blood analyses of C-peptide, total cholesterol, triglycerides, fatty acid profile, and short chain fatty acids after intervention with bread baked with yeast versus sourdough | 5 weeks | 
| Feces microbiota analysis performed with Bio-Me's Precision Microbiome Profiling platform (PMP™) | Feces analyses of microbiota after intervention with bread baked with yeast versus sourdough | 5 weeks | 
| Iron, selenium and zinc in blood | Blood analysis of iron, selenium and zinc after intervention with bread baked with yeast versus sourdough | 5 weeks |