PREDIMED Outcome-Wide: EVOO and Multiple Cardiovascular Endpoints

Olive oil has been linked to lower cardiovascular risk for decades, but most studies have not distinguished between extra virgin olive oil (rich in polyphenols) and common refined olive oil (largely stripped of them). In 2025, de Rojas and colleagues published an outcome-wide analysis in the American Heart Journal using PREDIMED data on 7,102 high-risk adults, and found that extra virgin olive oil was associated with a 25% lower risk of a broad composite of cardiovascular outcomes -- while common olive oil was not.

Why This Study Matters

Most epidemiological studies treat olive oil as a single category. That conflation is a problem. Extra virgin olive oil is mechanically pressed from olives and retains hundreds of milligrams per liter of polyphenols -- primarily hydroxytyrosol, oleuropein, and their derivatives. Common (refined) olive oil is chemically processed to neutralize defects, a step that removes most of the polyphenol content. The fatty acid profile is similar; the bioactive content is not.

The 2025 de Rojas analysis took the PREDIMED dataset -- a randomized trial originally designed to test Mediterranean diet effects on cardiovascular disease -- and applied an outcome-wide approach. Rather than examining one endpoint at a time, the authors looked at a composite of myocardial infarction, stroke, peripheral arterial disease, heart failure, atrial fibrillation, and cardiovascular death, plus each individual outcome.

Crucially, they separated EVOO intake from common olive oil intake using detailed dietary assessments collected annually throughout the trial. That separation is what makes this analysis different from earlier PREDIMED publications.

How It Was Designed

PREDIMED enrolled 7,447 participants aged 55 to 80 with no prior cardiovascular disease but at high cardiovascular risk. The current analysis includes 7,102 of those participants -- 57.5% women -- all free of cardiovascular disease at baseline. Median follow-up was 4.7 years.

Olive oil intake was assessed annually using validated food frequency questionnaires. The researchers calculated cumulative average intakes of extra virgin olive oil and common olive oil separately for each participant. This time-updated approach captures dietary change over the trial period rather than relying on a single baseline measurement.

The primary outcome was a composite of myocardial infarction, stroke, peripheral arterial disease, heart failure, atrial fibrillation, or cardiovascular death -- whichever occurred first. Individual outcomes were also analyzed. Statistical models were time-dependent Cox regressions adjusted for major confounders, including the original trial intervention arm. Participants were grouped into tertiles and into deciles for sensitivity analyses.

What They Found

Over 4.7 years, 621 participants experienced at least one cardiovascular event. The association with EVOO intake was strong, dose-dependent, and consistent across multiple individual outcomes.

Comparison	Mean Intake	HR (95% CI)	Risk Reduction	What It Measures
EVOO: top vs. bottom tertile	49.2 g/d vs. low	0.75 (0.60 to 0.94)	25% lower	Composite CVD outcome
EVOO: top vs. bottom decile	60.9 g/d vs. low	0.52 (0.35 to 0.79)	48% lower	Composite CVD outcome
Common olive oil (refined)	Mutually adjusted	0.93 (0.87 to 1.00)	Not significant	Composite CVD outcome

Green indicates a statistically significant protective association. HR values below 1.0 indicate lower risk. EVOO and common olive oil were mutually adjusted in the final models so each estimate reflects its independent contribution.

Reading the Results

The dose-response is striking. Participants in the top tertile of EVOO intake (mean 49 g/day -- roughly four tablespoons) had a 25% lower risk of the composite cardiovascular outcome. Participants in the top decile (mean 61 g/day) had a 48% lower risk. The risk reduction scales with intake, which is the pattern you would expect if EVOO is mechanistically protective rather than merely a marker of an otherwise healthier diet.

The EVOO-versus-common-oil split is the most important finding. When both forms of olive oil were entered into the same model and mutually adjusted, only EVOO retained a significant protective association. Common olive oil drifted toward null (HR 0.93, 95% CI 0.87 to 1.00). The fatty acid profiles of the two oils are nearly identical, but the polyphenol content is not -- and the cardiovascular signal tracks with the polyphenols, not the fat.

The benefit appeared across multiple individual outcomes. The authors report significant reductions in several specific cardiovascular endpoints, not just the composite. This consistency strengthens the inference: a finding that shows up across multiple independent endpoints is harder to attribute to chance than one that shows up in a single endpoint alone.

The analysis was outcome-wide, not single-endpoint. Earlier PREDIMED publications looked at single outcomes one at a time. This analysis ran the same exposure (EVOO intake) against a battery of outcomes simultaneously, which is a more rigorous test of whether the effect is broad-spectrum cardiovascular protection or narrow to one disease entity.

What Didn't Change

This is a secondary observational analysis of randomized trial data. The randomization in PREDIMED was to dietary advice arms (MedDiet + EVOO, MedDiet + nuts, low-fat control), not to specific EVOO doses. The exposure analyzed here -- cumulative average EVOO intake -- is an observational variable, not a randomized one. Residual confounding cannot be fully ruled out, although the authors adjusted for the original trial arm and for major cardiovascular risk factors.

Common olive oil intake was lower than EVOO intake in this Spanish cohort. The narrower distribution may have reduced statistical power to detect a small effect of common olive oil. The null finding for common olive oil should be read as evidence of no detectable effect at the intake levels observed, not as proof that common olive oil is inert.

Dietary assessment by food frequency questionnaire is imperfect. Annual repetition strengthens the measurement but does not eliminate misclassification.

Broader Context

The original PREDIMED trial established that a Mediterranean diet supplemented with EVOO reduces major cardiovascular events by approximately 30% compared with a low-fat control diet. Subsequent sub-analyses found reductions in stroke, atrial fibrillation, peripheral arterial disease, and diabetes incidence. This 2025 outcome-wide analysis pulls those threads together into a single coherent dose-response picture for EVOO specifically.

The polyphenol hypothesis is supported by independent lines of evidence. In 2011, the European Food Safety Authority authorized a health claim for olive oil polyphenols and the protection of blood lipids from oxidative damage, requiring at least 5 mg of hydroxytyrosol and its derivatives per 20 g of olive oil daily. Randomized trials of isolated hydroxytyrosol have shown reductions in oxidized LDL, inflammation markers, and DNA damage. The current analysis adds a real-world epidemiological data point: when polyphenols are retained (EVOO), cardiovascular benefit appears; when polyphenols are stripped (common olive oil), the benefit largely disappears.

This has consumer implications. The retail category labeled "olive oil" includes both EVOO and refined oils, often without clear distinction. The 2025 analysis suggests that the polyphenol content -- not the fact of being olive oil -- is what drives the cardiovascular signal.

Related Research

Continue exploring olive oil and polyphenol science:

• PREDIMED Republished: Mediterranean Diet + EVOO Cut Major CV Events by 30%
• A Polyphenol Signature in Urine Predicts Lower CV Risk in PREDIMED
• Within PREDIMED: Higher EVOO Intake Linked to 48% Lower CV Mortality

Source: View the original study on PubMed

Olivea's Dosage

The top tertile in this analysis consumed roughly 49 g/day of extra virgin olive oil -- about four tablespoons. The top decile consumed roughly 61 g/day. Our extra virgin olive oil is single-origin and third-party tested for polyphenol content. Each Olivea capsule delivers concentrated olive polyphenols for those who want the bioactive content without consuming larger volumes of oil. Our most recent certificate of analysis confirmed 23.5 mg of hydroxytyrosol per capsule.

According to PubMed, this study is indexed as PMID 40907633 (DOI: 10.1016/j.ahj.2025.08.021).

We share this research for transparency. This is an independent study -- we did not fund it, design it, or conduct it.

Editorial Information

Research note. This article summarizes third-party research published in a peer-reviewed journal. Olivea did not conduct or fund the study. Findings reflect the cited paper only and do not establish efficacy of Olivea products.

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