Tests high-phenolic olive oil against low-phenolic oil in adults with central obesity
Compares two olive oils over 8 weeks in adults with overweight or obesity.
Key facts
- Who runs it
- University of Peloponnese
- Where
- Kalamata, GreeceSee the site
- Trial code
- Registry title
- High Phenolic Olive Oil for Enhancing Metabolic Health: a Randomized-controlled Trial in Patients With cEntral Obesity (HOPE)
- Status
- Recruiting
- People taking part
- 80 people, planned
- Started
- 3 Mar 2025
- Expected to end
- May 2027
- Type of study
- Interventional, 2 groupsOne group gets an existing treatment, for comparison.
- Treatments tested
- Low phenolic olive oil
- High phenolic olive oil
- Record updated
- 3 March 2026
Who can take part
AI summary
From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.
The trial is looking for adults with overweight or obesity who have at least one metabolic problem. They will use a high or low phenolic olive oil for 8 weeks.
- Age
- 18 to 80 years.
- Sex
- Men and women can join.
- Disease stage
- Overweight or obesity (body mass index > 25 or waist circumference >94 cm (37 in) for men and >80 cm (31 in) for women), plus at least one metabolic abnormality: triglycerides ≥150 mg/dL (1.7 mmol/L) or low HDL cholesterol (≤40 mg/dL (1 mmol/L) in men, ≤50 mg/dL (1.3 mmol/L) in women); blood pressure ≥ 130/85 mm Hg; fasting blood sugar ≥100 mg/dL (5.6 mmol/L); or a standard drug treatment regimen.
- Earlier treatment
- People must not have used antioxidant-rich supplements, antibiotics, prebiotics or probiotics before the trial.
Main reasons for not taking part
- Another acute or chronic illness (for example infection, cancer, heart failure, kidney disease, autoimmune disease)
- Untreated diabetes
- Pregnancy or breastfeeding
- Psychiatric or mental disorder
- Drug or alcohol abuse
The registry criteria, word for word
Show all 11 criteriaShow less
Who can take part
- Adult men and women 18-80 years of age,
- Overweight/obesity (body mass index > 25 or waist circumference >94 cm for males and >80 cm for females), and
- The presence of at least one of the following metabolic abnormality: (1) triglyceride level ≥150 mg/dL or HDL cholesterol ≤40 mg/dL in men and ≤50 mg/dL in women; (2) increased blood pressure ≥ 130/85 mm Hg; (3) elevated fasting blood sugar ≥100 mg/dL; (4) standardized drug treatment regimen, and
- Provided signed informed consent for participation
Who cannot take part
- Concomitant acute or chronic disease (e.g., infection, cancer, chronic heart failure, kidney disease, autoimmune diseases like rheumatoid arthritis, inflammatory bowel diseases, Hashimoto),
- Drug and/or alcohol abuse,
- Untreated diabetes,
- Individuals with psychiatric or mental disorder,
- Women at pregnancy or lactation,
- Any use of antioxidant-phytochemical rich supplement, anti-, pre- or probiotics pre-intervention,
- Those who did not consent or were unable to provide consent
Check if you might fit
Answer for yourself. This is not a decision: only the study team can say whether you can take part.
- Are you between 18 and 80 years old?
Where in Greece
- Antikalamos Facilities of University of PeloponneseKalamata, GreeceContact: Aristea GioxariTaking people
About the trial
What the trial wants to find out
Olive oil is a fundamental component of the Mediterranean diet and a major source of monounsaturated fatty acids with well-established cardioprotective properties. When rich in phenolic compounds-such as hydroxytyrosol, tyrosol, oleuropein, oleocanthal, oleacein, and ligstroside aglycone-it is considered a functional food with antioxidant, anti-inflammatory, cardioprotective, chemoprotective, and neuroprotective effects. According to EU Regulation 432/2012, daily consumption of 20 g of extra virgin olive oil containing at least 5 mg of hydroxytyrosol and tyrosol derivatives (250 mg/kg) contributes to the protection of blood lipids from oxidative stress and qualifies for a health claim.
Read full original descriptionShow less
Overweight/obesity, characterized by excessive fat accumulation, is strongly associated with non-communicable diseases, including cardiovascular disease, type 2 diabetes, hypertension, certain cancers, and neurodegenerative disorders. Chronic low-grade inflammation and oxidative stress are key mechanisms underlying obesity-related metabolic disorders. Although dietary energy restriction remains the primary approach for weight management, growing research interest focuses on natural products rich in phenolic compounds as potential modulators of molecular pathways involved in central obesity.
However, robust clinical evidence in humans with central obesity and metabolic abnormalities remains limited. Therefore, this double-blind, randomized, controlled trial aims to investigate the effects of extra virgin, high-phenolic olive oil (HPOO) compared with low-phenolic olive oil (LPOO) in adults with overweight/obesity with metabolic abnormalities. Participants will consume the assigned olive oil type (HPOO or LPOO) for eight weeks.
At baseline and trial endpoint (8 weeks), data collection will include anthropometric measurements, dietary intake, biochemical indices, inflammatory and oxidative stress markers in blood samples, hormones, bioavailability of phenolic compounds, as well as lifestyle parameters i.e., health-related quality of life, physical activity levels, sleep quality. Ethical approval, informed consent, and data protection procedures will be strictly followed. Statistical analyses will be conducted using SPSS software (SPSS Inc, ΙΒΜ, Chicago, IL, USA).
The study is anticipated to explore whether consumption of high-phenolic olive oil favorably modulates markers related to obesity and metabolic abnormalities, while also improving nutritional status and quality-of-life parameters.
The 2 groups in the trial
- Control armSham treatment, for comparison
Participants assigned to the control arm receive olive oil with a low content in phenolic compounts.
Treatment: Low phenolic olive oil
- Intervention armExisting treatment, for comparison
Participants assigned to the intervention arm receive extra virgin olive oil rich in phenolic compounds.
Treatment: High phenolic olive oil
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Contact the study team: see the registry record → Contacts and Locations
Print a page for my doctorData and sources
- Registry record
- Listed on ClinicalTrials.gov.
- Official title
- High Phenolic Olive Oil for Enhancing Metabolic Health: a Randomized-controlled Trial in Patients With Central Obesity
- Plain-language title
- Tests high-phenolic olive oil against low-phenolic oil in adults with central obesityGenerated from the registry record. The registry title is the official one.
- AI summary
- From the trial's eligibility criteria. Read by machine on 13 November 2026.
- Fit questions
- Built from NCT07445503, who can take part
- Record updated
- 3 March 2026