A Study of Olive Oil Polyphenols (nutrients in plant-based food) and Cardiovascular Health

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Study coordinator
Name - Jody Randolph
Email - jmrandolph@ucdavis.edu
Phone - (530) 752-7620

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"Volunteer for research at UC Davis and contribute to discoveries that may improve health care for you, your family, and your community!"
Age: 20 to 45 years old
Healthy Volunteers: Yes
Keywords: olive oil, cardiovascular health
Type: Dietary Supplement study
50 Participants
You are invited to participate in a research 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. This includes levels of good and bad cholesterol, levels of inflammation, and levels of gene expression.

You are invited to be in this study because you are a healthy individual aged 20-45 with a BMI over 20 kg/m2.

Your participation in this research will involve 5 visits (including today’s initial screening) and will last about 8 weeks. There is a 2-week run-in period before starting the study. Then, two diet intervention periods each lasting two weeks, separated by a two-week washout period.
This study requires

Participation in this study will involve an initial two-week run in period to get used to the study diet.

After this two week period, you will be randomly assigned a study group. You will either take a high-polyphenol olive oil (extra virgin olive oil) or a low-polyphenol olive oil (refined olive oil).

You will consume the other oil during the second dietary intervention period.

During each phase of the study, you will be asked to come to the Ragle Human Nutrition Center after a 10-12 hour overnight fast.

At each visit, body measurements will be taken. You will be asked to eat a serving of olive oil and bread, and three urine and blood samples will be collected over the course of 4 hours.

This study will involve multiple blood draws and urine collections. These will be made across 5 visits at the Ragle Human Nutrition Research Center: - One blood draw during the initial screening visit to determine eligibility, - Three blood draws and urine collections at the start of each dietary intervention period, and - Three blood draws and urine collections at the end of each dietary intervention period.

Trained phlebotomists or nurses will be performing all of the blood draws.

Who can participate

Inclusion criteria:

  • 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/overwight group and ≥ 30 kg/m2 for the obese group will be recruited.

Exclusion criteria:

  • 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
  • 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, CBD oil
  • Taking exogenous hormones (e.g. hormonal birth control)
  • Poor venous access
  • Unwillingness to comply with study protocol
Benefits and risks of participating

We cannot promise any benefits to you as a result of taking part in this research study.


The study team will discuss the risks associated with taking part in this research study.
We will pay you $50 for each study visit. Payment will be provided at the end of the study visit in the form of a gift card. If you complete all the study visits, you will receive $200 for being in this study. If you choose to leave or we take you off the study for any reason, you will receive $50 for each completed study visit. No monetary compensation is given for the initial screening visit.
Study duration and period
You will be in the study for approximately 8 weeks. The initial run-in period will last for two weeks. This will be followed by a two-week dietary intervention period. A two-week washout period is next, followed by a final two-week dietary intervention period.
Recruitment period
From March 1, 2020
Research Topic
  • Healthy
  • Normal Weight
  • Overweight
  • Obese

Have any questions or want to learn more? Leave your contact details below and the research team will reach out to you.


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