An interventional study of Butter and Coconut oil in Short Chain Fatty Acids Concentration in Stools, Gut Microbiota Diversity and Composition and Blood Lipid Profiles, sponsored by University of Glasgow. Recruiting at 1 site in United Kingdom. Open to participants aged 20 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-24.
Sponsored by University of Glasgow · Not applicable, Interventional, and Basic science
This study will investigate how adding a specific type of dietary fat to daily meals for two weeks affects the gut bacteria and their activity. Participants will be randomly assigned to consume one of four types of fat: butter, coconut oil, olive oil, or sunflower oil (60 mL each day for 2 weeks). Stool and blood samples (after an overnight fast) will be collected at 3 time points during the study (Days 1, 7, and 22). These samples will be used to measure metabolites produced by gut bacteria, the types of bacteria present in the gut, blood lipids, and inflammatory markers. The study, based on previous in vitro findings, aims to understand whether different types of fats (based on their structure and level of saturation) have different effects on gut bacteria and their activity in healthy subjects.
This is a pilot, parallel, randomised controlled dietary intervention trial investigating the effects of dietary fat composition on gut microbiota and metabolic activity in healthy adults. Participants will be randomised to one of four intervention groups (butter, coconut oil, extra virgin olive oil, or sunflower oil), representing commonly consumed dietary fats that differ in fatty acid structure.
This study builds on prior in vitro findings demonstrating that fatty acid chain length and degree of saturation influence microbial fermentation pathways and short-chain fatty acid (SCFA) production.
The primary objective is to determine whether structurally distinct dietary fats differentially influence gut microbial activity and composition in vivo. Secondary objectives include assessing the effects on cardiometabolic and inflammatory markers. It is hypothesised that dietary fats differing in chain length and degree of saturation will differentially modulate gut microbiota metabolism, with potential systemic effects on circulating cardiometabolic and inflammatory markers.
A total of 64 healthy adults aged 20-50 years will be recruited from the Glasgow area. All study visits will take place at the New Lister Building, University of Glasgow. Participants will attend three study visits over a three-week period.
The study includes a one-week run-in period (normal habitual diet) followed by a two-week dietary intervention. During the intervention, participants will replace the majority of their habitual dietary fat intake with their allocated fat while maintaining their usual diet and lifestyle.
Biological samples (blood and stool) will be collected at each study visit (Day 1, 7 and 22) to assess study outcomes. Anthropometric measurements will also be recorded. Dietary intake, gastrointestinal symptoms, and compliance will be monitored using food diaries, symptom questionnaires, and adherence logs.
The sample size is based on anticipated changes in faecal SCFA concentrations. Based on prior data, 14 participants per group provides 80% power (P=0.05) to detect a mean change of 30 μmol/g (SD: 28 μmol/g). Allowing for a 10% drop-out rate, 16 participants per group (64 total) will be recruited. As this is a pilot study, this calculation is intended to inform a reasonable sample size rather than to ensure definitive hypothesis testing.
Exclusion Criteria:
Following a one week run-in period (habitual diet), participants will be assigned to consume butter as their primary dietary fat.
Other: Butter
Following a one week run-in period (habitual diet), participants will be assigned to consume coconut oil as their primary dietary fat.
Other: Coconut oil
Following a one week run-in period (habitual diet), participants will be assigned to consume olive oil as their primary dietary fat.
Other: Extra Virgin Olive Oil
Following a one week run-in period (habitual diet), participants will be assigned to consume sunflower oil as their primary dietary fat.
Other: Sunflower Oil
Participants will consume approximately 65 g/day of butter as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
Participants will consume approximately 55 g/day of coconut oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
Participants will consume 60 mL/day of olive oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
Participants will consume 60 mL/day of sunflower oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
Change in faecal short-chain fatty acid (SCFA) concentrations
Faecal concentrations of short-chain fatty acids (acetate, propionate, and butyrate) will be measured using gas chromatography to assess changes in gut microbial metabolic activity in response to dietary fat intervention.
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in gut microbiota composition
Gut microbiota composition will be assessed using 16S rRNA gene amplicon sequencing to evaluate changes in bacterial diversity and relative abundance following the dietary fat intervention.
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in blood lipid profile
Fasting blood concentrations of total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglycerides will be measured using standard enzymatic assays to assess cardiometabolic responses to the dietary fat intervention.
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in inflammatory markers
Circulating inflammatory markers (e.g., C-reactive protein (CRP), interleukin-6 (IL-6)) will be measured using ELISA or multiplex assays to assess systemic inflammatory responses to the dietary fat intervention.
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in faecal pH
Faecal pH will be measured to assess changes in the gut environment associated with microbial fermentation.
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in fasting glucose concentrations
Fasting blood glucose concentrations will be measured to assess changes in glucose metabolism in response to dietary fat intake.
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in faecal fat content
Faecal fat content will be measured to assess fat excretion and potential differences in fat digestion and absorption across intervention groups.
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Plan to share: Undecided
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University of Glasgow