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| Name | Class |
|---|---|
| University of Aarhus | OTHER |
| APC Microbiome Ireland | UNKNOWN |
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The goal of this intervention study is to compare the effects of fermented dairy and non-fermented dairy on bowel habits and cognitive performance in healthy women with defecations every other day or less. Furthermore, the study aims to explore underlying mechanisms linking the gut and the brain.
In addition, a sub-study will be conducted to explore differences in gut and brain measures between women with daily (reference group) and few (intervention group) weekly bowel movements, respectively, and to explore associations between measures of gut- and brain function.
Participants in the intervention study (n=60) will consume 300g of fermented dairy (yogurt) or non-fermented dairy (milk) daily for 4 weeks. After a washout period of at least 4 weeks, the participants will consume the alternative dairy product (yogurt or milk) for 4 weeks. The participants will collect samples at home and be tested at the institute before and after each condition (yogurt or milk).
Participants in the sub-study (n=40) will not undergo any dairy interventions and they will only take part in the baseline assessments.
Prior to all visits at the institute, the participants are asked to complete some study activities at home, including:
During all visits at the institute, the participants will undergo tests and measurements, including:
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Fermented dairy | Experimental | The fermented dairy product is Arla A38® naturel 1,5% yogurt. The yogurt contains Lactobacillus acidophilus culture. |
|
| Non-fermented dairy | Placebo Comparator | The non-fermented dairy product is Arla® Letmælk 1,5% (semi-skimmed milk). The fermented- and non-fermented dairy products are isocaloric and matched in macronutrient content. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Fermented dairy | Other | Participants will consume 300g of yogurt daily for 4 weeks as an integral part of their habitual diet, substituting other food items. |
|
| Measure | Description | Time Frame |
|---|---|---|
| Difference in change from baseline in defecation frequency between the interventions | Participants will report all bowel movements in a defecation diary in the week leading up to the intervention (baseline) and in the last week of the intervention (week 4) | Baseline and 4 weeks |
| Measure | Description | Time Frame |
|---|---|---|
| Difference in change from baseline in cognitive performance between the interventions | Changes in cognitive performance will be quantified by cognitive index comprising memory, attention, and psychomotor speed. A composite cognitive score will be calculated as the standard score. Z-score will be assessed with the baseline variance between 0 and 1. Memory: number of errors made by the participant. Lower number of errors indicating better outcome. Attention: latency (speed of response), probability of false alarms and sensitivity. Faster speed of response indicating better outcome and lower number of false alarms indicating better outcome. Psychomotor speed: lower values indicating faster reaction time and better outcome |
| Measure | Description | Time Frame |
|---|---|---|
| Difference in change from baseline in gut microbiota between the interventions | Fecal samples will be utilized for microbiota analyses (e.g., shotgun metagenome sequencing, 16S rRNA gene sequencing, and real-time PCR of selected bacterial taxa) | Baseline and 4 weeks |
| Difference in change from baseline in fecal pH between the interventions |
Inclusion Criteria:
Exclusion Criteria:
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Copenhagen, Department of Nutrition, Exercise and Sports | Copenhagen | Denmark |
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| ID | Term |
|---|---|
| D003248 | Constipation |
| ID | Term |
|---|---|
| D012817 | Signs and Symptoms, Digestive |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
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| ID | Term |
|---|---|
| D043302 | Cultured Milk Products |
| ID | Term |
|---|---|
| D008892 | Milk |
| D001628 | Beverages |
| D000066888 | Diet, Food, and Nutrition |
| D010829 | Physiological Phenomena |
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Two 4-week intervention periods separated by a washout period of at least 4 weeks.
The crossover intervention will include 60 participants. Another 40 participants will only complete the first (baseline) visit.
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| Non-fermented dairy | Other | Participants will consume 300g of milk daily for 4 weeks as an integral part of their habitual diet, substituting other food items. |
|
| Baseline and 4 weeks |
| Difference in change from baseline in phase-amplitude coupling between gastric slow-wave activity and cortical alpha activity between the interventions | Gastric and cortical electrical activity will be measured by electrogastrography (EGG) and electroencephalography (EEG), respectively, to investigate the phase-amplitude coupling between the infra-slow (~ 0.05 Hz) gastric phase and the amplitude of the cortical alpha rhythm (10-11 Hz) | Baseline and 4 weeks |
| Difference in change from baseline in whole gut transit time between the interventions | Whole gut transit time will be estimated by sweet-corn passage time | Baseline and 4 weeks |
| Difference in change from baseline in stool consistency between the interventions | Changes in stool consistency will be estimated by the Bristol Stool Scale. The scale ranges from type 1 (hard stool) to type 7 (loose stool) | Baseline and 4 weeks |
| Difference in change from baseline in stool moisture between the interventions | Fecal water content in percentage of stool weight will be measured | Baseline and 4 weeks |
| Difference in change from baseline in fecal abundance of Lactobacillus acidophilus between the interventions | Marker of compliance. Will be assessed by fecal microbiota sequencing | Baseline and 4 weeks |
| Difference in change from baseline in self-reported gastrointestinal symptoms between the interventions | Changes in subjective gastrointestinal symptoms will be reported by participants using a visual analog scale.The scale ranges from 0 (no symptoms) to 10 (very bad symptoms) | Baseline and 4 weeks |
pH will be measured in fecal samples |
| Baseline and 4 weeks |
| Difference in change from baseline in breath hydrogen and methane levels between the interventions | Changes in fasting breath hydrogen and methane concentrations will be measured in parts per million (PPM) in exhalations.Furthermore, breath hydrogen and methane concentrations will be measured (in PPM), twice daily (morning and evening) during each 4 week intervention using a portable breath analyzer | Baseline and 4 weeks |
| Difference in change from baseline in biomarkers of colonic fermentation between the interventions | Fecal samples will be used for measurements of biomarkers of colonic fermentation. These markers include fecal nitrogen to carbon ratio, fecal ammonia, fecal redox potential, fecal energy density, fecal calprotectin, fecal proteolytic and saccharolytic enzymatic activity | Baseline and 4 weeks |
| Difference in change from baseline in fecal short-chain fatty acids (SCFAs) between the interventions | Fecal concentrations of SCFAs will be quantified using mass spectrometry | Baseline and 4 weeks |
| Difference in change from baseline in fecal zonulin levels between the interventions | Fecal zonulin levels will be measured via fecal samples | Baseline and 4 weeks |
| Difference in change from baseline in plasma levels of lipopolysaccharide-binding protein (LBP) between the interventions | Plasma levels of LBP, a biomarker of intestinal permeability, will be measured by ELISA (enzyme-linked immunosorbent assay) | Baseline and 4 weeks |
| Difference in change from baseline in gut metabolome between the interventions | Gut (fecal) metabolomes will be assessed by metabolomics | Baseline and 4 weeks |
| Difference in change from baseline in urine metabolome between the interventions | Urine metabolomes will be assessed by untargeted metabolomics | Baseline and 4 weeks |
| Difference in change from baseline in plasma metabolome between the interventions | Plasma metabolomes will be assessed by metabolomics | Baseline and 4 weeks |
| Difference in change from baseline in inflammatory biomarkers between the interventions | The following inflammatory biomarkers will be measured in fasting blood samples: soluble urokinase plasminogen activator receptor (suPAR), C-reactive protein (CRP), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFα) | Baseline and 4 weeks |
| Difference in change from baseline in plasma levels of cortisol between the interventions | Plasma cortisol levels will be measured in fasting blood samples | Baseline and 4 weeks |
| Difference in change from baseline in biomarkers of glucose and lipid metabolism between the interventions | The following biomarkers of glucose and lipid metabolism will be measured in fasting blood samples: glucose, insulin, glucagon, total cholesterol, HDL cholesterol, LDL cholesterol and triglycerides | Baseline and 4 weeks |
| Difference in change from baseline in appetite hormones between the interventions | The following appetite hormones will be measured in fasting blood samples: glucagon-like peptide-1 (GLP-1), peptide YY (PYY), glucose-dependent insulinotropic polypeptide (GIP) and cholecystokinin (CCK) | Baseline and 4 weeks |
| Difference in change from baseline in plasma level of Brain Derived Neurotrophic Factor (BDNF) between the interventions | Plasma levels of BDNF will be measured by ELISA | Baseline and 4 weeks |
| Difference in change from baseline in self-reported stress and mood between the interventions | Self-reported stress and mood will be assessed by a 42 item scale that measures negative emotional states of depression, anxiety and stress (DASS-42). The scale ranges from 0 (did not apply to me at all) to 3 (applied to me very much, or most of the time) | Baseline and 4 weeks |
| Difference in change from baseline in self-reported sleeping patterns between the interventions | Sleep pattern and quality will be assessed by the Pittsburgh Sleep Quality Index (PSQI) at all visits. The PSQI consists of 19 items, summed into seven component scores and one overall composite score. Each item is rated on a scale from 0-3 with lower scores reflecting healthier sleep quality | Baseline and 4 weeks |
| Difference in change from baseline in resting-state cortical connectivity between the interventions | Resting-state cortical connectivity will be measured using EEG during a period of rest at all visits | Baseline and 4 weeks |
| Difference in change from baseline in event-related potentials evoked by a cognitive task between the interventions | Event-related potentials evoked by a cognitive task will be measured using EEG during a period of rest at all visits | Baseline and 4 weeks |
| Difference in change from baseline in quality of life between the interventions | Quality of life will be assessed by the 36-Item short form survey (SF-36) at all visits. A score ranging from 0 to 100 will be obtained. Higher scores indicate better quality of life | Baseline and 4 weeks |
| Difference in change from baseline in habitual diet between the interventions | Participants will record their food intake via MyFood24 for 3 days (one weekend day and two workdays) prior to all visits | Baseline and 4 weeks |
| D000074421 |
| Fermented Foods |
| D003611 | Dairy Products |
| D005502 | Food |
| D019602 | Food and Beverages |