Effects Of Dietary Fats on Gut Microbiota Composition and Metabolic Activity in Healthy Adults
University of Glasgow
64 participants
Mar 23, 2026
INTERVENTIONAL
Conditions
Summary
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.
Eligibility
Inclusion Criteria6
- Adults aged 20-50 years
- Body mass index (BMI) between 20 and 30 kg/m²
- Generally healthy
- Stable body weight (±2 kg) over the past 2 months
- Living in the Glasgow area
- Non-smoker
Exclusion Criteria14
- Use of antibiotics within the past 3 months
- Current use of medications affecting gut microbiota or cardiometabolic health
- Regular use of dietary supplements that may influence study outcomes (e.g. probiotics, prebiotics, vitamins, minerals, fish oil), unless willing to discontinue prior to study start
- Presence of chronic gastrointestinal, metabolic, cardiovascular, hepatobiliary, or pancreatic disease
- History of major gastrointestinal surgery
- Diagnosed diabetes or use of lipid-lowering therapy
- Known fat malabsorption disorders
- Pregnant or lactating women
- Post-menopausal women
- Following a restrictive or specific diet (e.g. vegan, ketogenic diet)
- Food allergies or intolerances relevant to study interventions (e.g. dairy, coconut)
- Recent significant weight change (±2 kg in the past month)
- High reliance on ready meals or takeaway foods (>7 main meals per week)
- Participation in another research study that may interfere with this study
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Interventions
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.
Locations(1)
View Full Details on ClinicalTrials.gov
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NCT07550023