Human Pilot Study for the Investigation of the Role of Bilberry and Olive Bioactives on Oxidative Stress Parameters and Inflammatory Markers. (BIOTRANSFORM)

June 15, 2026 updated by: Nikolaos Tentolouris, National and Kapodistrian University of Athens

A Blinded Placebo-controlled Human Pilot Study for the Investigation of the Role of Bilberry and Olive Bioactives on Oxidative Stress Parameters and Inflammatory Markers. Relevance in European Population

Numerous plant-based foods contain bioactive compounds, in particular polyphenols, which have antioxidant, anti-inflammatory, and metabolic regulatory effects. These so-called food bioactives (FB) are converted in the human organism, in particular by the gut microbiota and microsomal (liver/intestinal) metabolism, into numerous metabolites, which often represent the actual biologically active molecules. As part of the European HORIZON-MSCA Doctoral Network "BioTransform," two such food models are being studied as examples: 1. Olive products (Olea europaea L.) - representative of the Mediterranean diet, rich in secoiridoids and phenylethanols (especially hydroxytyrosol and tyrosol). 2.

Bilberry /blueberry (Vaccinium myrtillus L.) - representative of the Central European diet, rich in anthocyanosides. Two parallel human intervention studies will be conducted, one in Graz (WP1, DC5) and one in Athens (WP1, DC3). These pilot studies will generate biological samples (blood, urine, stool) and investigate the extent to which taking these standardized dietary supplements influences glucose metabolism and markers of oxidative stress and low-grade inflammation.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Greece
      • Athens, Greece, 11527
        • Laiko Hospital
        • Contact:
          • NIKOLAOS TENTOLOURIS, PROFESSOR MD, PHD
          • Phone Number: +30 2132061061
          • Email: ntentol@meduoa.gr

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 30-50 years old,
  • BMI> 25 kg/m2
  • prediabetic stage
  • hsCRP> 2mg/ L
  • HbA1c 5,7-6,4%
  • Impaired fasting glucose (IFG)
  • Caucasian

Exclusion Criteria:

  • No signed informed consent
  • Supplementation or probiotic usage in the past 8 weeks
  • Chronic gastrointestinal, inflammatory or metabolic diseases
  • Alcohol misuse
  • Pregnancy or breastfeeding
  • Acute infection during the past month

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: INTERVENTION WITH OLIVE OIL EXTRACTS
Group of 20 people will receive olive oil extract supplements and after the washout period will receive placebo.
Dietary supplement: supplementation, food
Through this pilot clinical study, the possible change of inflammatory and oxidative stress biomarkers in prediabetic, overweigh/ obese people will be observed. Blood, urine and stool samples will be collected, while weight mangment will also be controlled.
Other Names:
  • blood samples
  • Body weight and composition changes
  • oxidative stress and inflammatory biomarkers
  • urine samples
  • stool samples
Experimental: INTERVENTION WITH BILBERRY
Group of 20 participants will receive bilberry extract supplements and after the washout period a placebo phase.
Dietary supplement: supplementation, food
Through this pilot clinical study, the possible change of inflammatory and oxidative stress biomarkers in prediabetic, overweigh/ obese people will be observed. Blood, urine and stool samples will be collected, while weight mangment will also be controlled.
Other Names:
  • blood samples
  • Body weight and composition changes
  • oxidative stress and inflammatory biomarkers
  • urine samples
  • stool samples

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in inflammatory and oxidative stress markers
Time Frame: 14 weeks
The changes in the inflammatory and oxidative stress markers will be assessed through blood samples and the biomarkers: hsCRP, IL-6, TNF-a, total antioxidant capacity, ratio glutathione/ oxidiced glutathion
14 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Lipid profile
Time Frame: 14 weeks
Blood samples: TCHOL, HDL, LDL, TG
14 weeks
Inflammatory profile
Time Frame: 14 weeks
Blood samples: ICAM-1, VCAM-1, CRP-C
14 weeks
Anthropometric profile
Time Frame: 14 weeks
Body measurements: BMI and body weight changes
14 weeks
Metabolic profile
Time Frame: 14 weeks
Urine and plasma samples: metabolite profile in urine and plasma
14 weeks
Microbiome profile
Time Frame: 14 weeks
Stool samples: microbiome diversity, microbiome composition changes, and microbiome functionality
14 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National and Kapodistrian University of Athens

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2026

Primary Completion (Estimated)

July 1, 2029

Study Completion (Estimated)

October 31, 2029

Study Registration Dates

First Submitted

June 9, 2026

First Submitted That Met QC Criteria

June 15, 2026

First Posted (Actual)

June 22, 2026

Study Record Updates

Last Update Posted (Actual)

June 22, 2026

Last Update Submitted That Met QC Criteria

June 15, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 999643007
  • 101225248 (Other Grant/Funding Number: Marie Skłodowska-Curie Actions)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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