Apple Intake Effect on Faecal Metabolome

This pilot dietary intervention study aimed to investigate whether short-term consumption of apples influences the human faecal metabolomic profile. Apples are a commonly consumed source of dietary fibre, particularly pectin, which undergoes microbial fermentation in the colon and may lead to measurable metabolic changes. Healthy adult volunteers were instructed to consume three apples per day for three consecutive days under free-living conditions. Faecal samples were collected before and after the intervention and analysed using proton nuclear magnetic resonance (¹H NMR) spectroscopy to assess changes in metabolite concentrations. The study sought to explore whether metabolomic profiling can detect functional microbial responses to increased fruit intake and provide preliminary insight into the metabolic impact of short-term dietary fibre exposure.

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Key information

Conditions

Healthy Adult Participants

Age range

18 year–30 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Czech University of Life Sciences Prague

Prague, 16500, Czechia

About this study

This study was designed as a single-arm exploratory dietary intervention to evaluate short-term metabolic responses to increased intake of fruit-derived dietary fibre. Participants were instructed to consume three fresh Gala apples per day for three consecutive days while otherwise maintaining their habitual diet and lifestyle. The intervention was conducted under free-living conditions to reflect realistic dietary behaviour.

Faecal samples were collected immediately before the intervention and after completion of the three-day exposure period. Samples were processed using standardized laboratory protocols to obtain aqueous extracts suitable for metabolomic analysis. Proton nuclear magnetic resonance (¹H NMR) spectroscopy was employed to generate quantitative metabolic profiles, enabling detection of metabolites associated with microbial fermentation and host-microbe metabolic interactions.

Metabolite concentrations were quantified using targeted profiling approaches, and both multivariate and univariate statistical analyses were applied to assess intervention-related changes in the faecal metabolome. The study was intended to provide mechanistic insight into how short-term consumption of a commonly consumed fruit may influence gut microbial metabolic activity, and to evaluate the feasibility of metabolomics-based assessment of dietary exposures in small-scale human intervention studies.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Healthy adults aged 18-30 years
Able and willing to consume apples daily during the intervention period
Willing to provide stool samples before and after the intervention
Not following a specific prescribed diet
Physically able to maintain usual daily activities during the study
Able to provide written informed consent

Exclusion criteria

Diagnosed gastrointestinal, metabolic, or chronic systemic disease
Use of antibiotics, probiotics, or regular medication affecting digestion in the period prior to enrolment
Known allergy or intolerance to apples or other fruits
Current participation in another dietary or clinical study
Following a medically prescribed or restrictive diet
Pregnancy or breastfeeding

Treatment and study plan

Apple consumption

Other

The intervention consisted of short-term added intake of fruit-derived dietary fibre through consumption of three whole apples daily over a three-day period. Participants were asked to maintain habitual dietary patterns apart from the prescribed apple consumption.

Primary outcomes

Change from baseline in faecal metabolomic profile assessed by ¹H NMR spectroscopy

Time frame: Baseline and immediately after completion of the 3-day dietary intervention

The outcome measure represents the change in concentrations of detected faecal metabolites between pre- and post-intervention samples, reflecting potential alterations in gut microbial metabolic activity associated with increased fruit intake.

Sponsors and collaborators

Lead sponsor

Czech University of Life Sciences Prague

Other

Registry information

Official study title

Impact of Short-term Apple Intake on the Human Faecal Metabolome Assessed by 1H NMR Spectroscopy

Acronym: AppleNMR

Important dates

Study start: 2023
Primary completion: 2024
Study completion: 2025
First posted: Mar 30, 2026
Registry last updated: Apr 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed