Oxidative StressOliherbCTNCT06983145
Postprandial Effect of Olive Leaf Biscuits and Tea Consumption on Blood Biomarkers in Healthy Individuals
A study testing Olive Leaf tea in people with Oxidative Stress and Inflammation Biomarkers, run by University of the Aegean at 1 site in Greece.
Trial summary
This randomized controlled nutritional intervention study aims to investigate the bioactivity of dried olive leaves in biscuit and tea preparations, focusing on their postprandial effects on selected biomarkers and plasma antioxidant status. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Oxidative Stress, Inflammation Biomarkers
- What is being tested?
- Olive Leaf tea
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteGreece
- Study dates
- 20 Nov 2024to 30 Sep 2025
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy, without underlying diseases (e.g. diabetes, cardiovascular, hypertension, hypercholesterolemia, hypertriglyceridemia, morbid obesity with BMI>40kg/m2)
- Aged 18-65 years at the start of the study
- Signed written consent to participate in the study and access by doctors to their medical history (diseases, medication)
Who cannot join
- People with a BMI >40
- Professional athletes
- People taking contraceptive treatment in the last 3 months
- People with a history of food allergy with hypersensitivity to any of the components of the administered product (e.g. milk protein or allergy-hypersensitivity to plants of the Oleaceae family) People taking supplements (e.g. antioxidants) or drugs that affect intestinal function (e.g. antibiotics) in the last 3 months or medication (hypoglycemic drugs or antihypertensive drugs or diuretics) that may interact with the administered product
- People taking any medication or supplement that may affect metabolism (e.g. GLP-1 analogues and receptor agonists, caffeine supplement, supplements weight loss/gain)
- Pregnant, lactating or menopausal women
Show all 12Show fewer
- Individuals with substance abuse (drugs) or chronic alcoholism or total daily alcohol intake > 50 g/d
- Individuals with a chronic condition (history of cardiovascular disease, cancer, diabetes, hypertension, hyperlipidemia, neurological and neuropsychological disorders, active liver disease, severe renal dysfunction, severe stroke and conditions associated with increased risk of bleeding)
- Individuals with any other serious medical condition that may affect the individual's ability to participate in a nutritional intervention study.
- Individuals whose dietary preferences do not allow them to do so (e.g., vegetarians, vegans)
- Individuals who are not willing to comply with the study protocol and the periods of fasting and eating
- Individuals who are considered unreliable by the researcher or have a shorter life expectancy than the expected duration of the study, due to some disease or if they are in any condition that, in the opinion of the researcher, does not allow their safe participation in the study (drug addiction, alcohol abuse)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Study of the Postprandial Effect of Olive Leaf Biscuits and Tea Consumption on Plasma Antioxidant Status, as Well as on Metabolic Syndrome Indicators, in Healthy Individuals
This randomized controlled nutritional intervention study aims to investigate the bioactivity of dried olive leaves in biscuit and tea preparations, focusing on their postprandial effects on selected biomarkers and plasma antioxidant status. Healthy volunteers aged 18 to 65 from Limnos, Greece, will participate in the study, held at the Human Nutrition Unit of the University of the Aegean.
The study will last 15 days and features a cross-over design involving three groups:
Read more
Control Group: Consumes biscuits made with butter, flour, sugar, and caramel coloring, along with natural mineral water.
Intervention Group A: Receives the same biscuits with added dried olive leaf powder, accompanied by the same water.
Intervention Group B: Eats the standard biscuits with olive leaf tea instead of water. On each study day, participants will consume their meal over 15 minutes, followed by the liquid within 10 minutes. After a 7-day washout period, the groups will switch treatments for the second phase. The procedure will be repeated on the 15th day, ensuring that all participants experience each condition. Blood samples will be collected before and at 60, 120, and 240 minutes post-meal for analysis. Statistical processing will then be conducted to evaluate the effects on biomarkers and antioxidant status.
Read the detailed description
This is the protocol of a randomized controlled nutritional intervention
- clinical study to investigate the bioactivity of preparations (biscuits and tea) with dried olive leaves. This is a nutritional intervention - clinical study of cross-over design (cross over design: acute study). The main objective of the study is to investigate the postprandial effect of olive leaves, on selected biomarkers and on the antioxidant status of plasma. The participants of the study will be healthy volunteers, aged 18-65 years, who will come from areas of Greece and will be based on the island of Limnos, in order to be able to be present on the days of the study. The study will be carried out in the specially designed space of the Human Nutrition Unit, University of the Aegean, in collaboration with external doctors. The total duration of the study will be 15 days (3 axes). Participants will be randomly divided into three groups. On the first day, the first group will consume a meal rich in carbohydrates and fats, which will consist of 2-3 biscuits made with butter, flour and sugar and drops of caramel coloring (E150a), along with a glass of natural mineral water with the addition of caramel coloring (E150a) at a refrigerator temperature of ~4°C (control group), the second group 2-3 biscuits made with butter, flour and sugar and dried olive leaf powder, along with a glass of natural mineral water with the addition of caramel coloring (E150a) at a refrigerator temperature of ~4°C (intervention group A) and the third group 2-3 biscuits made with butter, flour and sugar and drops of caramel coloring (E150a), along with a glass of tea made from dried olive leaves and natural mineral water at refrigerator temperature ~4°C (intervention group B). In all groups, the meal (control or intervention) will be consumed first and the liquid (control or intervention) will be consumed immediately afterwards. The total time for the meal (biscuits) will be 15 minutes and in the next 10 minutes, the liquid (olive leaf tea or water with caramel coloring) must also be consumed. After 7 days (washout period), the same volunteers will come to the specially designed area and the procedure will be repeated, with the difference that the control group on day 1 will belong to intervention group A, intervention group A will belong to intervention group B and intervention group B will belong to the control group. Finally, on the 15th day, the procedure will be repeated with the same volunteers, where the control group of the 1st day will now belong to the intervention group B, the intervention group A will belong to the control group and the intervention group B will belong to the intervention group A. On all 3 days, blood will be taken for analysis from the participants before, as well as 60, 120 and 240 minutes after the meals. Statistical processing of the results of the analyses will follow to present data regarding the postprandial levels of selected biomarkers and the antioxidant status of plasma.
- Conditions
- Oxidative Stress, Inflammation Biomarkers
- Being tested
- Olive Leaf tea
- Keywords
- olive leaf tea, olive leaf biscuits, inflammation, oxidative stress, acute clinical study
- Medical subject headings
- Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Olive Leaf teaOther
Individuals will consume 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with 1.25 g. dried olive leaves)
| Study group | Role | What they receive |
|---|---|---|
| Control | Placebo comparator | The individuals will consume 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) for the control group Receives: Other: Olive Leaf tea |
| Olive Leaf biscuit | Active comparator | The individuals will consume 2-3 pieces of biscuits with 1.25 g. dried olive leaf powder (total 121.25 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) Receives: Other: Olive Leaf tea |
| Olive Leaf tea | Experimental | Individuals will consume 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with 1.25 g. dried olive leaves) Receives: Other: Olive Leaf tea |
What is being measured
The primary outcome is the main question the study is designed to answer.
Total Antioxidant Capacity Concentration (mmol/L)
Changes of Total Antioxidant Capacity Concentration from baseline
Measured: 1 hour, 2 hours, 4 hours
C- Reactive Protein Concentration (mg/dL)
Changes of C-Reactive Protein Concentration from baseline
Measured: 1 hour, 2 hours, 4 hours
Secondary outcomes (8)
Total Cholesterol Concentration (mg/dL)
Changes of Total Cholesterol Concentration from baseline
Measured: 1 hour, 2 hours, 4 hours
High Density Cholesterol
Changes of High Density Cholesterol from baseline
Measured: 1 hour, 2 hours, 4 hours
Low Density Cholesterol Concentration (mg/dL)
Changes of Low Density Cholesterol Concentration from baseline
Measured: 1 hour, 2 hours, 4 hours
Glucose Concentration (mg/dL)
Changes of Glucose Concentration from baseline
Measured: 1 hour, 2 hours, 4 hours
Triglycerides
Changes of Triglycerides from baseline
Measured: 1 hour, 2 hours, 4 hours
Uric Acid Concentration (mg/dL)
Changes of Uric Acid Concentration from baseline
Measured: 1 hour, 2 hours, 4 hours
Systolic Blood Pressure
Changes of Systolic Blood Pressure from baseline
Measured: 1 hour, 2 hours, 4 hours
Diastolic Blood Pressure (mmHg)
Changes of Diastolic Blood Pressure Concentration from baseline
Measured: 1 hour, 2 hours, 4 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 May 2025
- Study start20 Nov 2024
- Primary completion11 Mar 2025
- Study completion30 Sep 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Oxidative StressStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Screening
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Control: 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) for the control group Olive Leaf biscuit: 2-3 pieces of biscuits with 1.25 g. dried olive leaf powder (total 121.25 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) for the intervention group A and Olive leaf tea: 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with 1.25 g. dried olive leaves) for the intervention group B.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of the Aegean
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, ANTONIOS KOUTELIDAKIS, University of the Aegean
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06983145
- Sponsor's protocol ID
- OliherbCT
- Acronym
- OliherbCT
- Status last verified
- May 2025
- First submitted
- 29 Mar 2025
- Last updated
- 21 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Due to sensitivity of data
Study at a glance
From the registry record, last updated by the sponsor on 21 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study of the Postprandial Effect of Olive Leaf Biscuits and Tea Consumption on Plasma Antioxidant Status, as Well as on Metabolic Syndrome Indicators, in Healthy Individuals
- ClinicalTrials.gov ID
- NCT06983145
- Acronym / sponsor ID
- OliherbCT / OliherbCT
- Conditions
- Oxidative Stress, Inflammation Biomarkers
- Keywords
- olive leaf tea, olive leaf biscuits, inflammation, oxidative stress, acute clinical study
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- University of the AegeanUniversity, hospital or other
- Study start
- 20 Nov 2024 (actual)
- Primary completion
- 11 Mar 2025 (actual)
- Study completion
- 30 Sep 2025 (estimated)
- First posted
- 21 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This randomized controlled nutritional intervention study aims to investigate the bioactivity of dried olive leaves in biscuit and tea preparations, focusing on their postprandial effects on selected biomarkers and plasma antioxidant status. Healthy volunteers aged 18 to 65 from Limnos, Greece, will participate in the study, held at the Human Nutrition Unit of the University of the Aegean.
The study will last 15 days and features a cross-over design involving three groups:
Control Group: Consumes biscuits made with butter, flour, sugar, and caramel coloring, along with natural mineral water.
Intervention Group A: Receives the same biscuits with added dried olive leaf powder, accompanied by the same water.
Intervention Group B: Eats the standard biscuits with olive leaf tea instead of water. On each study day, participants will consume their meal over 15 minutes, followed by the liquid within 10 minutes. After a 7-day washout period, the groups will switch treatments for the second phase. The procedure will be repeated on the 15th day, ensuring that all participants experience each condition. Blood samples will be collected before and at 60, 120, and 240 minutes post-meal for analysis. Statistical processing will then be conducted to evaluate the effects on biomarkers and antioxidant status.
Detailed description
This is the protocol of a randomized controlled nutritional intervention
- clinical study to investigate the bioactivity of preparations (biscuits and tea) with dried olive leaves. This is a nutritional intervention - clinical study of cross-over design (cross over design: acute study). The main objective of the study is to investigate the postprandial effect of olive leaves, on selected biomarkers and on the antioxidant status of plasma. The participants of the study will be healthy volunteers, aged 18-65 years, who will come from areas of Greece and will be based on the island of Limnos, in order to be able to be present on the days of the study. The study will be carried out in the specially designed space of the Human Nutrition Unit, University of the Aegean, in collaboration with external doctors. The total duration of the study will be 15 days (3 axes). Participants will be randomly divided into three groups. On the first day, the first group will consume a meal rich in carbohydrates and fats, which will consist of 2-3 biscuits made with butter, flour and sugar and drops of caramel coloring (E150a), along with a glass of natural mineral water with the addition of caramel coloring (E150a) at a refrigerator temperature of ~4°C (control group), the second group 2-3 biscuits made with butter, flour and sugar and dried olive leaf powder, along with a glass of natural mineral water with the addition of caramel coloring (E150a) at a refrigerator temperature of ~4°C (intervention group A) and the third group 2-3 biscuits made with butter, flour and sugar and drops of caramel coloring (E150a), along with a glass of tea made from dried olive leaves and natural mineral water at refrigerator temperature ~4°C (intervention group B). In all groups, the meal (control or intervention) will be consumed first and the liquid (control or intervention) will be consumed immediately afterwards. The total time for the meal (biscuits) will be 15 minutes and in the next 10 minutes, the liquid (olive leaf tea or water with caramel coloring) must also be consumed. After 7 days (washout period), the same volunteers will come to the specially designed area and the procedure will be repeated, with the difference that the control group on day 1 will belong to intervention group A, intervention group A will belong to intervention group B and intervention group B will belong to the control group. Finally, on the 15th day, the procedure will be repeated with the same volunteers, where the control group of the 1st day will now belong to the intervention group B, the intervention group A will belong to the control group and the intervention group B will belong to the intervention group A. On all 3 days, blood will be taken for analysis from the participants before, as well as 60, 120 and 240 minutes after the meals. Statistical processing of the results of the analyses will follow to present data regarding the postprandial levels of selected biomarkers and the antioxidant status of plasma.
Study design
- Primary purpose
- Screening
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 3
- Model description
- Control: 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) for the control group Olive Leaf biscuit: 2-3 pieces of biscuits with 1.25 g. dried olive leaf powder (total 121.25 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) for the intervention group A and Olive leaf tea: 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with 1.25 g. dried olive leaves) for the intervention group B.
| Arm | Type | Receives |
|---|---|---|
| Control | Placebo comparator | Other: Olive Leaf teaThe individuals will consume 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) for the control group |
| Olive Leaf biscuit | Active comparator | Other: Olive Leaf teaThe individuals will consume 2-3 pieces of biscuits with 1.25 g. dried olive leaf powder (total 121.25 g) and a glass (250 mL) of tea (natural mineral water with caramel coloring) |
| Olive Leaf tea | Experimental | Other: Olive Leaf teaIndividuals will consume 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with 1.25 g. dried olive leaves) |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Healthy, without underlying diseases (e.g. diabetes, cardiovascular, hypertension, hypercholesterolemia, hypertriglyceridemia, morbid obesity with BMI>40kg/m2)
- Aged 18-65 years at the start of the study
- Signed written consent to participate in the study and access by doctors to their medical history (diseases, medication)
Key exclusion criteria (12 listed)
- People with a BMI >40
- Professional athletes
- People taking contraceptive treatment in the last 3 months
- People with a history of food allergy with hypersensitivity to any of the components of the administered product (e.g. milk protein or allergy-hypersensitivity to plants of the Oleaceae family) People taking supplements (e.g. antioxidants) or drugs that affect intestinal function (e.g. antibiotics) in the last 3 months or medication (hypoglycemic drugs or antihypertensive drugs or diuretics) that may interact with the administered product
- People taking any medication or supplement that may affect metabolism (e.g. GLP-1 analogues and receptor agonists, caffeine supplement, supplements weight loss/gain)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Olive Leaf teaIndividuals will consume 2-3 pieces of biscuits with caramel coloring (total 120 g) and a glass (250 mL) of tea (natural mineral water with 1.25 g. dried olive leaves) | Other | Control, Olive Leaf biscuit, Olive Leaf tea |
Primary outcome
Total Antioxidant Capacity Concentration (mmol/L)
Time frame: 1 hour, 2 hours, 4 hours
Changes of Total Antioxidant Capacity Concentration from baseline
C- Reactive Protein Concentration (mg/dL)
Time frame: 1 hour, 2 hours, 4 hours
Changes of C-Reactive Protein Concentration from baseline
8 secondary outcomes
Total Cholesterol Concentration (mg/dL)
Time frame: 1 hour, 2 hours, 4 hours
High Density Cholesterol
Time frame: 1 hour, 2 hours, 4 hours
Low Density Cholesterol Concentration (mg/dL)
Time frame: 1 hour, 2 hours, 4 hours
Glucose Concentration (mg/dL)
Time frame: 1 hour, 2 hours, 4 hours
Triglycerides
Time frame: 1 hour, 2 hours, 4 hours
Uric Acid Concentration (mg/dL)
Time frame: 1 hour, 2 hours, 4 hours
Systolic Blood Pressure
Time frame: 1 hour, 2 hours, 4 hours
Diastolic Blood Pressure (mmHg)
Time frame: 1 hour, 2 hours, 4 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 May 2025.
- Individual participant dataSharing planned: No. Due to sensitivity of data
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Olive Leaf tea in people with Oxidative Stress and Inflammation Biomarkers, run by University of the Aegean at 1 site in Greece.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 21 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Greece. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Total Antioxidant Capacity Concentration (mmol/L) (time frame: 1 hour, 2 hours, 4 hours). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 May 2025.