Apple Intake Effect on Faecal Metabolome (AppleNMR)

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

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.

Study Overview

• Status: Completed
• Conditions: Healthy Adult Participants
• Intervention / Treatment: Other: Apple consumption

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Czechia
  • Prague
    • Prague, Prague, Czechia, 16500
      • Czech University of Life Sciences Prague

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Apple Dietary Intervention; Participants consumed three fresh apples per day for three consecutive days under free-living conditions while maintaining their habitual diet. Faecal samples were collected before and after the intervention to assess changes in metabolomic profiles.	Other: Apple consumption; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in faecal metabolomic profile assessed by ¹H NMR spectroscopy	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.	Baseline and immediately after completion of the 3-day dietary intervention

Collaborators and Investigators

• Sponsor: Czech University of Life Sciences Prague

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2023
• Primary Completion (Actual): August 30, 2024
• Study Completion (Actual): February 25, 2025

Study Registration Dates

• First Submitted: March 24, 2026
• First Submitted That Met QC Criteria: March 24, 2026
• First Posted (Actual): March 30, 2026

Study Record Updates

• Last Update Posted (Actual): April 1, 2026
• Last Update Submitted That Met QC Criteria: March 27, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: NMR; Dietary fiber; Apples; Pectin fermentation; Faecal metabolome
• Other Study ID Numbers: EK/81/2023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual-level participant data will not be publicly shared due to privacy considerations and ethical restrictions. De-identified summary data supporting the study findings may be available from the investigators upon reasonable request.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No