Extra Virgin Olive Oil in the Diet: Research and Cautions
What cohort studies, a major Mediterranean-diet trial and reviews of trials found about olive oil as a food, where results are mixed, and why it is not proven alone.
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Quick answer
Large observational studies link more olive oil in the diet with fewer heart events and deaths. The best-known trial tested a whole Mediterranean-style diet with extra virgin olive oil, not the oil alone. Reviews of trials that tested extra virgin olive oil by itself found changes in insulin measures but not in cholesterol or blood pressure. This page covers olive oil as food. For skin and home use see olive oil in Natural Ingredients.
What olive oil is
Olive oil is the oil from the fruit of Olea europaea L. (family Oleaceae). [1] "Extra virgin" is a grade of olive oil. The studies below say whether they tested extra virgin oil or olive oil in general, and results for one do not automatically apply to the other.What the research found
| Question | What the source found | Strength of evidence | Design and people |
|---|---|---|---|
| Heart events on a Mediterranean diet | In the PREDIMED trial, 7,447 people at high heart risk got a Mediterranean diet with free extra virgin olive oil, one with mixed nuts, or advice to cut dietary fat. The hazard ratio for major cardiovascular events was 0.69 (95% CI 0.53 to 0.91) with olive oil versus the control diet. [2] | Promising but limited | Randomized, Spain, ages 55-80, median 4.8 years |
| Olive oil intake and disease in cohorts | A 2024 review of 30 articles (about 2.7 million people) linked higher olive oil intake to lower risk of cardiovascular disease (RR 0.85) and all-cause death (RR 0.85), with no link to cancer. [3] | Promising but limited (observational) | Prospective cohorts |
| Amount in cohorts | Another review estimated 16% lower cardiovascular risk and 22% lower type 2 diabetes risk for each additional 25 g a day, again with no link to cancer. [4] | Promising but limited (observational) | 24 cohorts and one trial |
| Extra virgin oil alone, in trials | A 2024 review of 33 trials (2,020 people) found lower insulin and insulin resistance scores, and no significant effect on blood sugar, cholesterol, blood pressure, body weight measures or inflammation markers. [5] | Mixed | Randomized trials |
| Olive oil compared with avocado oil | Proper evidence not found. | Insufficient evidence | We searched Europe PMC for studies naming both oils and found only a rat study, a laboratory heating study and a newsletter question |
Reading the results
- PREDIMED has a caveat. The authors withdrew their first 2013 report after finding protocol deviations, including some people who were not randomized, and published revised estimates. [2] The control group was told to reduce dietary fat, so the trial compares diets, not oil against no oil.
- Cohort studies cannot prove cause. People who use more olive oil may also eat and live differently. The 2024 review began by noting that earlier reports on these links were inconsistent. [3]
- Official recognition. The US FDA's list of qualified health claims includes an entry titled "Monounsaturated Fatty Acids from Olive Oil and Coronary Heart Disease", dated November 1, 2004. We read the title and date only, not the wording. [6]
Related
Avocado: research and cautions · Studied dietary patterns · Seed oils and inflammation claims checkedFrequently asked questions
Is extra virgin olive oil good for you?
Observational studies link more olive oil to lower cardiovascular risk. [3] Trials of extra virgin oil alone found changes in insulin measures but not in cholesterol or blood pressure. [5]
Did the PREDIMED trial prove olive oil prevents heart disease?
It found fewer major cardiovascular events with a Mediterranean diet plus extra virgin olive oil than with a reduced-fat diet, but the first report was withdrawn and revised. [2] It tested a whole diet.
Does olive oil reduce cancer risk?
Two cohort reviews found no link between olive oil intake and cancer incidence. [3][4]
Is olive oil better than avocado oil?
Proper evidence not found. We searched for studies comparing the two in people and found none.
Does olive oil cause weight gain?
The 2024 review of trials found no significant effect of extra virgin oil on body mass index or waist measures. [5] Weight advice is outside this page.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and who should ask
The sources we read did not describe medicine interactions for olive oil eaten as food. We did not read sources on olive oil for infants, pregnancy or special diets. If you follow a low-fat diet for a medical reason, or take medicines and have questions about foods, ask a pharmacist or clinician. See medicine interactions and foods for cholesterol and heart health.
References
- GBIF Secretariat. Olea europaea L., accepted name, family Oleaceae. Read 2026-10-23 (GBIF species match API).
- Estruch R et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. N Engl J Med 2018. PMID 29897866. Read 2026-10-23.
- Olive oil intake and cardiovascular disease, cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective cohort studies. Food Funct 2024. Read 2026-10-23 (abstract via Europe PMC).
- Effect of olive oil consumption on cardiovascular disease, cancer, type 2 diabetes, and all-cause mortality: A systematic review and meta-analysis. Clin Nutr 2022. Read 2026-10-23 (abstract via Europe PMC).
- Effect of Extra Virgin Olive Oil on Anthropometric Indices, Inflammatory and Cardiometabolic Markers: a Systematic Review and Meta-Analysis of Randomized Clinical Trials. J Nutr 2024. Read 2026-10-23 (abstract via Europe PMC).
- U.S. Food and Drug Administration. Qualified Health Claims: Letters of Enforcement Discretion (list of claim titles and dates; letters not read). Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.