HealthyNCT04149288
Olive Oil Polyphenols and Cardiovascular Health Biomarkers
A study testing High-polyphenol olive oil and Low-polyphenol olive oil in people with Healthy and Normal Weight, run by University of California, Davis at 1 site in United States.
Trial summary
The purpose of this research is to investigate whether consuming two different kinds of olive oil will change risk factors related to cardiovascular disease, including levels of good and bad cholesterol, levels of inflammation, and levels of gene expression. Read more about this study
- Who is it for?
- Ages 20 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy, Normal Weight, Overweight
- What is being tested?
- High-polyphenol olive oil and Low-polyphenol olive oil
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 44 participants
- Where
- 1 siteUnited States
- Study dates
- 6 Oct 2021to 22 Aug 2026
- 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 20 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Generally healthy male and female subjects within the range of 20-45 years of age and BMI range of 18.5-29.9 kg/m2 for the healthy weight/overweight group and ≥ 30 kg/m2 for the obese group will be recruited.
Who cannot join
- Adults unable to consent, individuals who are not yet adults (infants, children, teenagers), pregnant or lactating women, women planning to become pregnant in the next two months and prisoners will be specifically excluded
- Documented chronic diseases including diabetes, thyroid disease, kidney disease, metabolic syndrome, active cancer, previous cardiovascular events, history of gastric bypass or other GI issues related to fat absorption
- History of dyslipidemia or abnormal blood glucose levels (total cholesterol >240 mg/dL, elevated fasting blood glucose levels >125 mg/dL)
- Allergy to olives, inability to tolerate gluten or multiple allergies/intolerances that would significantly limit food intake
- Smoker or living with a smoker, illicit drug use, consuming >1 alcoholic drink/day, vaporizer and/or electronic cigarette use
- Extreme dietary or exercise patterns
Show all 11Show fewer
- Recent weight fluctuations (>10% in the last 6 months)
- Taking prescription lipid medications or supplements that may affect lipoprotein metabolism, >1 g of fish oil/day, antioxidant supplements, cannabidiol (CBD) oil
- Taking exogenous hormones (e.g. hormonal birth control)
- Poor venous access
- Unwillingness to comply with study protocol
Trial locations and contacts
1 site in 1 country.
United States1 site
Ragle Human Nutrition Center
Davis, California, 95616
About this study
The purpose of this research is to investigate whether consuming two different kinds of olive oil will change risk factors related to cardiovascular disease, including levels of good and bad cholesterol, levels of inflammation, and levels of gene expression.
Read the detailed description
The purpose of this research is to investigate whether consuming two different kinds of olive oil will change risk factors related to cardiovascular disease, including levels of good and bad cholesterol, levels of inflammation, and levels of gene expression. Healthy individuals aged 20-45 with a BMI over 20 kg/m2 are eligible to participate. The study involves 5 visits (1 initial screening and 4 study visits) and will last about 8 weeks. There is a 2-week run-in period before starting the study, followed by two diet intervention periods each lasting two weeks, separated by a two-week washout period.
Participation in this study will involve an initial two-week run in period to become accustomed to the study diet. After this two week period, participants will be randomly selected to start either a high-polyphenol olive oil (extra virgin olive oil) or a low-polyphenol olive oil (refined olive oil); participants will consume the other oil during the second dietary intervention period lasting 2 weeks. During each phase of the study, participants will be asked to come to the University of California, Davis campus after a 10-12 hour overnight fast. At each visit, body measurements will be taken, a serving of olive oil and bread will be eaten, and three urine and blood samples will be collected over the course of 4 hours. Each study visit will involve three blood draws by a trained nurse or phlebotomist.
During the 8 weeks of the study, all olive products such as olives, olive oil, and olive containing products will need to be avoided. The study will provide olive oil to be eaten at home for each intervention phase. Additionally, the investigators will ask that nuts and high-polyphenol foods (mostly fruits and vegetables) be avoided in the diet. Detailed food diaries will be filled out and brought to study visits.
- Conditions
- Healthy, Normal Weight, Overweight, Obese
- Being tested
- High-polyphenol olive oil, Low-polyphenol olive oil
- Medical subject headings
- Overweight, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High-polyphenol olive oilDietary supplement
High-polyphenol olive oil will be provided to study participants to consume at home. Participants will be asked to consume 40 mL each day for 2 weeks.
Low-polyphenol olive oilDietary supplement
Low-polyphenol olive oil will be provided to study participants to consume at home. Participants will be asked to consume 40 mL each day for 2 weeks.
| Study group | Role | What they receive |
|---|---|---|
| High-polyphenol olive oil | Active comparator | Participants will consume 40 mL of high-polyphenol olive oil each day at home for 2 weeks. Receives: Dietary Supplement: High-polyphenol olive oil |
| Low-polyphenol olive oil | Active comparator | Participants will consume 40 mL of low-polyphenol olive oil each day at home for 2 weeks. Receives: Dietary Supplement: Low-polyphenol olive oil |
What is being measured
The primary outcome is the main question the study is designed to answer.
Assessing the influence of olive oil polyphenols on cholesterol efflux
Cholesterol efflux will be measured by assessing changes in reverse cholesterol transport rate in separated serum at each study time point (baseline, 2 hour, 4 hour) using a commercially available assay kit at each of the 4 study visits.
Measured: Through study completion, an average of 8 weeks
Assessing the influence of olive oil polyphenols on cholesterol ester transfer protein activity (CETP)
Changes in CETP activity will be measured at each study time point (baseline, 2 hour, 4 hour) in plasma at each of the 4 study visits. The isolated plasma will be co-incubated with donor and acceptor molecules using a commercially available assay kit.
Measured: Through study completion, an average of 8 weeks
Assessing the influence of olive oil polyphenols on circulating oxidized LDL
Measure for changes in circulating levels of oxidized LDL in separated plasma at each study time point (baseline, 2 hour, 4 hour) using a commercially available ELISA kit; measured in units of U/L at each of the 4 study visits.
Measured: Through study completion, an average of 8 weeks
Assessing the influence of olive oil polyphenols on blood lipid measurements
Measure for changes in the levels of HDL and LDL in separated plasma; measured in units of mg/dL. Blood will be assessed for the fasting (baseline) sample only at each of the 4 study visits.
Measured: Through study completion, an average of 8 weeks
Assessing the influence of olive oil polyphenols on paraoxonase-1 (PON-1) activity
Measure for changes in PON-1 activity in separated plasma at each study time point (baseline, 2 hour, 4 hour) at each of the 4 study visits. Activity will be calculated based on linear rates of hydrolysis of phenyl acetate to phenol.
Measured: Through study completion, an average of 8 weeks
Assessing the influence of olive oil polyphenols on peripheral blood mononuclear cells (PBMC) using ex vivo stimulation assays
Measurement of changes in PBMC derived cytokines as a marker of inflammation at each study time point (baseline, 2 hour, 4 hour) at each of the 4 study visits. Assessment will be based on an increase or decrease in concentration in pg/ml.
Measured: Through study completion, an average of 8 weeks
Secondary outcomes (1)
Assessing the influence of olive oil polyphenols on gene expression in mirco RNA in PBMCs
Measure level of gene expression in micro RNA from PBMCs at each study time point (baseline, 2 hour, 4 ) at each of the 4 study visits. Assessment will be based on fold change between study arms.
Measured: Through study completion, an average of 8 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Nov 2019
- Study start6 Oct 2021
- Primary completion22 Aug 2026 (estimated)
- Study completion22 Aug 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by University of California, DavisThe sponsor's other registered studies.
- 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 44 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Davis
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04149288
- Sponsor's protocol ID
- 1484263
- Status last verified
- Jan 2026
- First submitted
- 30 Sep 2019
- Last updated
- 29 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Olive Oil Polyphenols and Cardiovascular Health Biomarkers
- ClinicalTrials.gov ID
- NCT04149288
- Acronym / sponsor ID
- 1484263
- Conditions
- Healthy, Normal Weight, Overweight, Obese
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 44 participants (estimated)
- Lead sponsor
- University of California, DavisUniversity, hospital or other
- Study start
- 6 Oct 2021 (actual)
- Primary completion
- 22 Aug 2026 (estimated)
- Study completion
- 22 Aug 2026 (estimated)
- First posted
- 4 Nov 2019 (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.
The purpose of this research is to investigate whether consuming two different kinds of olive oil will change risk factors related to cardiovascular disease, including levels of good and bad cholesterol, levels of inflammation, and levels of gene expression.
Detailed description
The purpose of this research is to investigate whether consuming two different kinds of olive oil will change risk factors related to cardiovascular disease, including levels of good and bad cholesterol, levels of inflammation, and levels of gene expression. Healthy individuals aged 20-45 with a BMI over 20 kg/m2 are eligible to participate. The study involves 5 visits (1 initial screening and 4 study visits) and will last about 8 weeks. There is a 2-week run-in period before starting the study, followed by two diet intervention periods each lasting two weeks, separated by a two-week washout period.
Participation in this study will involve an initial two-week run in period to become accustomed to the study diet. After this two week period, participants will be randomly selected to start either a high-polyphenol olive oil (extra virgin olive oil) or a low-polyphenol olive oil (refined olive oil); participants will consume the other oil during the second dietary intervention period lasting 2 weeks. During each phase of the study, participants will be asked to come to the University of California, Davis campus after a 10-12 hour overnight fast. At each visit, body measurements will be taken, a serving of olive oil and bread will be eaten, and three urine and blood samples will be collected over the course of 4 hours. Each study visit will involve three blood draws by a trained nurse or phlebotomist.
During the 8 weeks of the study, all olive products such as olives, olive oil, and olive containing products will need to be avoided. The study will provide olive oil to be eaten at home for each intervention phase. Additionally, the investigators will ask that nuts and high-polyphenol foods (mostly fruits and vegetables) be avoided in the diet. Detailed food diaries will be filled out and brought to study visits.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| High-polyphenol olive oil | Active comparator | Dietary Supplement: High-polyphenol olive oilParticipants will consume 40 mL of high-polyphenol olive oil each day at home for 2 weeks. |
| Low-polyphenol olive oil | Active comparator | Dietary Supplement: Low-polyphenol olive oilParticipants will consume 40 mL of low-polyphenol olive oil each day at home for 2 weeks. |
Who may qualify
- Ages
- 20 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Generally healthy male and female subjects within the range of 20-45 years of age and BMI range of 18.5-29.9 kg/m2 for the healthy weight/overweight group and ≥ 30 kg/m2 for the obese group will be recruited.
Key exclusion criteria (11 listed)
- Adults unable to consent, individuals who are not yet adults (infants, children, teenagers), pregnant or lactating women, women planning to become pregnant in the next two months and prisoners will be specifically excluded
- Documented chronic diseases including diabetes, thyroid disease, kidney disease, metabolic syndrome, active cancer, previous cardiovascular events, history of gastric bypass or other GI issues related to fat absorption
- History of dyslipidemia or abnormal blood glucose levels (total cholesterol >240 mg/dL, elevated fasting blood glucose levels >125 mg/dL)
- Allergy to olives, inability to tolerate gluten or multiple allergies/intolerances that would significantly limit food intake
- Smoker or living with a smoker, illicit drug use, consuming >1 alcoholic drink/day, vaporizer and/or electronic cigarette use
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 |
|---|---|---|
| High-polyphenol olive oilHigh-polyphenol olive oil will be provided to study participants to consume at home. Participants will be asked to consume 40 mL each day for 2 weeks. | Dietary supplement | High-polyphenol olive oil |
| Low-polyphenol olive oilLow-polyphenol olive oil will be provided to study participants to consume at home. Participants will be asked to consume 40 mL each day for 2 weeks. | Dietary supplement | Low-polyphenol olive oil |
Primary outcome
Assessing the influence of olive oil polyphenols on cholesterol efflux
Time frame: Through study completion, an average of 8 weeks
Cholesterol efflux will be measured by assessing changes in reverse cholesterol transport rate in separated serum at each study time point (baseline, 2 hour, 4 hour) using a commercially available assay kit at each of the 4 study visits.
Assessing the influence of olive oil polyphenols on cholesterol ester transfer protein activity (CETP)
Time frame: Through study completion, an average of 8 weeks
Changes in CETP activity will be measured at each study time point (baseline, 2 hour, 4 hour) in plasma at each of the 4 study visits. The isolated plasma will be co-incubated with donor and acceptor molecules using a commercially available assay kit.
Assessing the influence of olive oil polyphenols on circulating oxidized LDL
Time frame: Through study completion, an average of 8 weeks
Measure for changes in circulating levels of oxidized LDL in separated plasma at each study time point (baseline, 2 hour, 4 hour) using a commercially available ELISA kit; measured in units of U/L at each of the 4 study visits.
Assessing the influence of olive oil polyphenols on blood lipid measurements
Time frame: Through study completion, an average of 8 weeks
Measure for changes in the levels of HDL and LDL in separated plasma; measured in units of mg/dL. Blood will be assessed for the fasting (baseline) sample only at each of the 4 study visits.
Assessing the influence of olive oil polyphenols on paraoxonase-1 (PON-1) activity
Time frame: Through study completion, an average of 8 weeks
Measure for changes in PON-1 activity in separated plasma at each study time point (baseline, 2 hour, 4 hour) at each of the 4 study visits. Activity will be calculated based on linear rates of hydrolysis of phenyl acetate to phenol.
Assessing the influence of olive oil polyphenols on peripheral blood mononuclear cells (PBMC) using ex vivo stimulation assays
Time frame: Through study completion, an average of 8 weeks
Measurement of changes in PBMC derived cytokines as a marker of inflammation at each study time point (baseline, 2 hour, 4 hour) at each of the 4 study visits. Assessment will be based on an increase or decrease in concentration in pg/ml.
1 secondary outcome
Assessing the influence of olive oil polyphenols on gene expression in mirco RNA in PBMCs
Time frame: Through study completion, an average of 8 weeks
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 29 Jan 2026.
- Learn more or sign up for the study here!Link provided by the sponsor.
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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 High-polyphenol olive oil and Low-polyphenol olive oil in people with Healthy and Normal Weight, run by University of California, Davis at 1 site in United States.
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 1 inclusion and 11 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 29 Jan 2026. 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 United States. 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. 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?
Assessing the influence of olive oil polyphenols on cholesterol efflux (time frame: Through study completion, an average of 8 weeks). The study lists 6 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 29 Jan 2026.