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Research · Food and drink

Olive oil

In cohorts, each extra 25 g a day of olive oil was linked to 16% less cardiovascular disease, 22% less type 2 diabetes and 11% lower death. A Mediterranean diet with extra virgin olive oil cut heart events in one large trial. Trials found no blood pressure change. Many retail extra virgin oils failed purity tests.

Add to Bio HackChecked 2026-11-13
Status
A food, not a regulated health product. FDA allows a qualified health claim that "limited and not conclusive scientific evidence suggests that eating about 2 tablespoons (23 grams) of olive oil daily may reduce the risk of coronary heart disease", when it replaces saturated fat without adding calories [1]. The Dietary Guidelines for Americans, 2025-2030 name olive oil as an oil to prioritize when cooking with or adding fats [2].
Also called
extra virgin olive oil, EVOO, virgin olive oil, refined olive oil, light olive oil, olive pomace oil, high-polyphenol olive oil, olive oil shot
Studied for
heart health, longer life, cholesterol, blood pressure, blood sugar, type 2 diabetes prevention, inflammation, cancer prevention, antioxidants

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help5

Reported risks1

What it was studied for, and what was found

Shown to help5

Strong

Death from any cause

Linked to 11% lower death per extra 25 g of olive oil a day, and 19% lower at over 7 g a day than never, in cohorts.

Compared with 25 g a day less, in a dose-response model [3]; the bottom third of intake [4]; people who never or rarely used olive oil [5]

The numbers and sources
Effect
Pooled cohorts found a relative risk of 0.89 (95% CI 0.85 to 0.93) per extra 25 g a day [3]. The top against the bottom third of intake of monounsaturated fat sources gave 0.89 (95% CI 0.83 to 0.96), and in subgroups only olive oil, not monounsaturated fat in general, was linked to lower death [4]. In US nurses and health professionals followed 28 years, more than 7 g a day was linked to lower death than never or rarely using it (HR 0.81, 95% CI 0.78 to 0.84), and to lower death from heart disease, cancer, neurodegenerative and respiratory disease. Olive oil did not differ from other vegetable oils combined [5].
Population
733,420 participants and 174,081 deaths [3]. 841,211 participants in 32 cohorts [4]. 60,582 women and 31,801 men free of heart disease and cancer at the start [5].
Sources
[3], [4], [5]
Caveats
Observational. Olive oil users may differ in diet, income and other habits. Heterogeneity was present for death [3]. Replacing butter, margarine, mayonnaise or dairy fat with olive oil was linked to lower death, but replacing other vegetable oils was not [5].
Strong

Heart disease and stroke in cohorts

Linked to 16% less cardiovascular disease per extra 25 g a day in cohorts, mostly through less stroke. Coronary heart disease alone showed no clear link.

Compared with 25 g a day less, in a dose-response model [3][6]; the bottom third of intake [4]

The numbers and sources
Effect
Each extra 25 g a day was linked to less cardiovascular disease (RR 0.84, 95% CI 0.76 to 0.94) [3]. An earlier pooling found less stroke (RR 0.74, 95% CI 0.60 to 0.92) and fewer combined cardiovascular events (RR 0.82, 95% CI 0.70 to 0.96), and no significant link with coronary heart disease in cohorts (RR 0.96, 95% CI 0.78 to 1.18) [6]. The top third of intake was linked to fewer cardiovascular events and strokes than the bottom third [4].
Population
806,203 participants and 49,223 cardiovascular events in cohorts and one trial [3]. 101,460 participants for coronary heart disease and 38,673 for stroke [6]. 32 cohorts [4].
Sources
[3], [6], [4]
Caveats
Observational, with heterogeneity. Small-study effects were suspected [6].
Limited

Heart attack, stroke and cardiovascular death in a trial

One large trial found fewer major cardiovascular events on a Mediterranean diet with extra virgin olive oil than on low-fat advice, 3.8% against 4.4%.

Compared with a control diet of advice to reduce dietary fat [7]

The numbers and sources
Effect
Over a median 4.8 years, major cardiovascular events (heart attack, stroke or cardiovascular death) occurred in 3.8% of the extra virgin olive oil group and 4.4% of the control group (HR 0.69, 95% CI 0.53 to 0.91). Results were similar after leaving out 1,588 participants whose assignment departed from the protocol [7].
Population
7,447 Spanish adults aged 55 to 80 at high cardiovascular risk, 57% women, assigned to one of three diets [7].
Sources
[7]
Caveats
The olive oil was given with a whole Mediterranean diet and education sessions, so the trial does not isolate olive oil. The first report was withdrawn over randomization problems [7]. The mediterranean-diet page covers this trial's weight, diabetes and cognition results.
Why limited
This rests on one trial, of 7,447 people. Strength counts independent studies that agree, so one trial is limited at any size.
Strong

Type 2 diabetes

Linked to 16% to 22% lower type 2 diabetes at higher olive oil intake, in two pooled analyses of cohorts.

Compared with the lowest intake category [8]; 25 g a day less, in a dose-response model [3]

The numbers and sources
Effect
The highest against the lowest intake was linked to lower type 2 diabetes risk (RR 0.84, 95% CI 0.77 to 0.92), with a nonlinear pattern [8]. Each extra 25 g a day was linked to 22% lower risk (RR 0.78, 95% CI 0.69 to 0.87), with no evidence of heterogeneity [3].
Population
4 cohorts with 15,784 cases [8]. 680,239 participants and 13,389 cases [3].
Sources
[8], [3]
Caveats
Observational, and the two analyses share cohorts.
Moderate

Blood sugar in people with type 2 diabetes

Shown to lower HbA1c by 0.27 points and fasting glucose by 0.44 mmol/L in people with type 2 diabetes, in pooled trials against control groups.

Compared with control groups in the trials pooled [8]

The numbers and sources
Effect
In people with type 2 diabetes, olive oil lowered HbA1c (mean difference -0.27%, 95% CI -0.37 to -0.17) and fasting plasma glucose (-0.44 mmol/L, 95% CI -0.66 to -0.22) more than in control groups [8].
Population
People with type 2 diabetes in trials among the 29 pooled [8].
Sources
[8]
Caveats
The abstract does not describe the control groups. The authors note the finding applies to olive oil as a food, not its single components [8].

Mixed results3

Moderate

Cholesterol

Shown to raise HDL cholesterol slightly in trials. LDL fell with high-polyphenol olive oil, but other plant oils lowered LDL more than olive oil did.

Compared with other plant oils [9]; low-polyphenol olive oil [10][11]

The numbers and sources
Effect
Against other plant oils, olive oil raised HDL more (1.37 mg/dL, 95% CI 0.4 to 2.36) and lowered total cholesterol (by 6.27 mg/dL), LDL (by 4.2 mg/dL, 95% CI 1.4 to 7.01) and triglycerides (by 4.31 mg/dL) less. Apolipoproteins A1 and B did not differ [9]. Against low-polyphenol olive oil, high-polyphenol oil lowered total cholesterol by 4.5 mg/dL and raised HDL by 2.37 mg/dL [10]. A later pooling found higher HDL (1.13 mg/dL, 95% CI 0.45 to 1.80), lower LDL only at the highest polyphenol level (-4.28 mg/dL) and no change in total cholesterol [11].
Population
1,089 participants in 27 randomized trials [9]. 26 randomized trials [10]. 10 randomized trials, mostly crossover, in mostly healthy Europeans [11].
Sources
[9], [10], [11]
Caveats
The changes are a few mg/dL. The comparison decides the direction: olive oil looks favorable against low-polyphenol olive oil and less favorable for LDL against other plant oils.
Moderate

Inflammation

Mixed results: one pooled analysis found C-reactive protein fell 0.64 mg/L with olive oil, while a later one found no change in C-reactive protein or interleukin-6.

Compared with control groups, with control diets that varied [12]; trials comparing olive oil or flaxseed oil with controls [13]

The numbers and sources
Effect
Olive oil lowered C-reactive protein (mean difference -0.64 mg/L, 95% CI -0.96 to -0.31, 15 trials) and interleukin-6 (-0.29) and raised flow-mediated dilation by 0.76% against controls [12]. A pooling of trials in adults with normal or mildly raised blood pressure found no effect on C-reactive protein (8 trials) or interleukin-6 (3 trials) [13].
Population
3,106 participants in 30 randomized trials [12]. 17 randomized trials, 14 of olive oil [13].
Sources
[12], [13]
Caveats
The first review calls for conservative reading because olive oil was given as a supplement or within a diet and control diets varied [12].
Moderate

Cancer

Mixed results: pooled case-control and cohort studies linked high intake to 31% less cancer, while a pooling of prospective cohorts found no link.

Compared with the lowest intake [14]; 25 g a day less, in a dose-response model [3]

The numbers and sources
Effect
The highest olive oil intake was linked to lower odds of any cancer (RR 0.69, 95% CI 0.62 to 0.77), including breast, gastrointestinal and urinary tract cancer [14]. In prospective cohorts, each extra 25 g a day was not significantly linked to cancer (RR 0.94, 95% CI 0.86 to 1.03) [3].
Population
37 case-control studies and 8 cohorts with 929,771 participants [14]. 1,285,064 participants and 58,892 cancer cases in cohorts and one trial [3].
Sources
[14], [3]
Caveats
Case-control studies ask about diet after diagnosis and are prone to recall bias. The cohort-only analysis found no link [3].

Not shown to help1

Moderate

Blood pressure

Not shown to lower blood pressure in pooled trials of adults with normal or mildly raised blood pressure.

Compared with control groups in randomized trials [13]

The numbers and sources
Effect
Pooled trials found no significant change in systolic (mean difference -0.48 mmHg, 95% CI -1.76 to 0.80) or diastolic pressure (-0.47 mmHg, 95% CI -1.33 to 0.39) [13]. A review of high-polyphenol olive oil reported blood pressure improvements only in subgroups and single trials [10].
Population
17 randomized trials, 14 of olive oil and 3 of flaxseed oil, in adults with normal blood pressure or at risk of hypertension [13].
Sources
[13], [10]
Caveats
The pooled analysis combined olive oil and flaxseed oil trials. The authors call for longer, higher-dose trials [13].

Amounts studied

Cohort reviews modeled risk per extra 25 g a day [3], or compared top and bottom thirds of intake [4]. In US cohorts the top group used more than 0.5 tablespoon, over 7 g, a day [5]. The FDA claim refers to about 2 tablespoons (23 g) a day replacing saturated fat [1]. Polyphenol trials compared olive oils of different polyphenol content, from 0 to 600 mg per kg of oil [11]. The trial evidence for heart events comes from extra virgin olive oil provided within a Mediterranean diet [7].

Risks

Reported risks1

LimitedHow often is not known

Extra virgin olive oil that fails purity tests

Testing studies found 62.5% of 88 US products labeled extra virgin failed authenticity criteria, and 19 of 70 Brazilian samples were judged adulterated.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Of 88 products labeled extra virgin olive oil bought in Maryland, 33 (37.5%) met all three authenticity criteria. The other 55 appeared mixed with refined olive oil or other vegetable oils, or were of lower grade [15]. Of 70 samples sold as extra virgin in Brazil, 19 were judged adulterated, and 5 carried benzo[a]pyrene above the European and Brazilian limit of 2.0 µg/kg [16].
Population
88 retail products in one US city [15]. 70 retail samples in Brazil [16].
Sources
[15], [16]
Caveats
Two markets at single time points. The US study used a rapid screening method. Judged on International Olive Council fatty acid ranges alone, fewer than 10% would have been classed as not extra virgin [15].

Claims tested and not found

  1. That olive oil lowers blood pressure. Pooled trials found no significant change in systolic or diastolic pressure [13].
  2. That olive oil lowers LDL cholesterol more than other cooking oils. Against other plant oils, olive oil lowered LDL by 4.2 mg/dL less [9].
  3. That olive oil protects against cancer. Prospective cohorts found no significant link between intake and cancer [3].
  4. That olive oil is linked to lower death than other vegetable oils. In 92,383 US adults, olive oil did not differ from other vegetable oils combined [5].

Related

Mediterranean diet

Sources

  1. US Food and Drug Administration. Letter Responding to Health Claim Petition dated August 28, 2003: Monounsaturated Fatty Acids from Olive Oil and Coronary Heart Disease. FDA Qualified Health Claims, Letters of Enforcement Discretion. 2004. http://wayback.archive-it.org/7993/20171114183649/https://www.fda.gov/Food/IngredientsPackagingLabeling/LabelingNutrition/ucm072963.htm
  2. US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans, 2025-2030. realfood.gov. 2026. https://cdn.realfood.gov/DGA.pdf
  3. Martínez-González MA, Sayón-Orea C, Bullón-Vela V, et al. Effect of olive oil consumption on cardiovascular disease, cancer, type 2 diabetes, and all-cause mortality: A systematic review and meta-analysis. Clinical Nutrition. 2022. https://doi.org/10.1016/j.clnu.2022.10.001
  4. Schwingshackl L, Hoffmann G. Monounsaturated fatty acids, olive oil and health status: a systematic review and meta-analysis of cohort studies. Lipids in Health and Disease. 2014. https://doi.org/10.1186/1476-511x-13-154
  5. Guasch-Ferré M, Li Y, Willett WC, et al. Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among U.S. Adults. Journal of the American College of Cardiology. 2022. https://doi.org/10.1016/j.jacc.2021.10.041
  6. Martínez-González MA, Dominguez LJ, Delgado-Rodríguez M. Olive oil consumption and risk of CHD and/or stroke: a meta-analysis of case-control, cohort and intervention studies. British Journal of Nutrition. 2014. https://doi.org/10.1017/s0007114514000713
  7. Estruch R, Ros E, Salas-Salvadó J, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. The New England Journal of Medicine. 2018. https://doi.org/10.1056/nejmoa1800389
  8. Schwingshackl L, Lampousi AM, Portillo MP, et al. Olive oil in the prevention and management of type 2 diabetes mellitus: a systematic review and meta-analysis of cohort studies and intervention trials. Nutrition and Diabetes. 2017. https://doi.org/10.1038/nutd.2017.12
  9. Ghobadi S, Hassanzadeh-Rostami Z, Mohammadian F, et al. Comparison of blood lipid-lowering effects of olive oil and other plant oils: A systematic review and meta-analysis of 27 randomized placebo-controlled clinical trials. Critical Reviews in Food Science and Nutrition. 2019. https://doi.org/10.1080/10408398.2018.1438349
  10. George ES, Marshall S, Mayr HL, et al. The effect of high-polyphenol extra virgin olive oil on cardiovascular risk factors: A systematic review and meta-analysis. Critical Reviews in Food Science and Nutrition. 2019. https://doi.org/10.1080/10408398.2018.1470491
  11. Zupo R, Castellana F, Crupi P, et al. Olive Oil Polyphenols Improve HDL Cholesterol and Promote Maintenance of Lipid Metabolism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Metabolites. 2023. https://doi.org/10.3390/metabo13121187
  12. Schwingshackl L, Christoph M, Hoffmann G. Effects of Olive Oil on Markers of Inflammation and Endothelial Function: A Systematic Review and Meta-Analysis. Nutrients. 2015. https://doi.org/10.3390/nu7095356
  13. McNabb TB, Young I, Newman RG, et al. Supplementation of Olive Oil and Flaxseed Oil on Blood Pressure and Inflammation in Healthy and At-Risk Adults: A Systematic Literature Review and Meta-Analysis. Current Hypertension Reviews. 2025. https://doi.org/10.2174/0115734021337760241104063418
  14. Markellos C, Ourailidou ME, Gavriatopoulou M, et al. Olive oil intake and cancer risk: A systematic review and meta-analysis. PLOS ONE. 2022. https://doi.org/10.1371/journal.pone.0261649
  15. Mossoba MM, Azizian H, Fardin-Kia AR, et al. First Application of Newly Developed FT-NIR Spectroscopic Methodology to Predict Authenticity of Extra Virgin Olive Oil Retail Products in the USA. Lipids. 2017. https://doi.org/10.1007/s11745-017-4250-5
  16. Tfouni SAV, Reis RM, Amaro NdPL, et al. Adulteration and Presence of Polycyclic Aromatic Hydrocarbons in Extra Virgin Olive Oil Sold on the Brazilian Market. Journal of the American Oil Chemists' Society. 2017. https://doi.org/10.1007/s11746-017-3046-3

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