CORDIOPREV: 7 Years of Mediterranean Diet for Secondary CV Prevention

This 7-year randomized controlled trial in 1,002 patients with established coronary heart disease, published in The Lancet, tested whether a Mediterranean diet rich in extra virgin olive oil outperforms a low-fat diet for preventing repeat cardiovascular events. CORDIOPREV reported a 25-28% reduction in the composite endpoint of myocardial infarction, revascularization, ischemic stroke, peripheral artery disease, and cardiovascular death -- making it the longest secondary-prevention RCT of dietary pattern to date.

Why This Study Matters

PREDIMED established that the Mediterranean diet reduces first-time cardiovascular events in high-risk adults with no diagnosed heart disease. The open question after PREDIMED was whether the same diet would help people who had already had a cardiac event. That's a clinically distinct population. Patients with established coronary heart disease are already on aggressive statin therapy, antiplatelet drugs, and often beta-blockers and ACE inhibitors. Adding a dietary intervention on top of optimized pharmaceutical care is a harder test -- the bar for benefit is higher because the medications are already pulling residual risk down.

CORDIOPREV was designed to answer that question. The team at the Reina Sofia University Hospital in Cordoba enrolled patients with documented coronary heart disease, randomized them 1:1 to a Mediterranean diet or a low-fat diet, and followed them for seven years -- one of the longest dietary RCTs ever conducted. According to PubMed, the primary results were published in The Lancet on May 4, 2022 (DOI: 10.1016/S0140-6736(22)00122-2).

The result: the Mediterranean diet group had significantly fewer major cardiovascular events. The hazard ratios across multiple adjusted models ranged from 0.72 to 0.75 in favor of the Mediterranean diet, with the effect concentrated in men (HR 0.67, P = 0.013) and not significant in the smaller subgroup of 175 women.

How It Was Designed

The basics are in the study design bar above: 1,002 patients, 7-year follow-up, single-center RCT in Cordoba, Spain, two-arm parallel design. A few details deserve highlighting.

All participants had established coronary heart disease -- they had already experienced an event or had documented coronary artery disease. The mean age was 59.5 years, and 82.5% were men. Patients continued their standard cardiovascular medications throughout the trial; the dietary intervention was added on top of, not in place of, pharmaceutical care. This is the design that mirrors real-world clinical decision-making.

Randomization was performed by the Andalusian School of Public Health -- an external body, not the investigators themselves. Clinical investigators, outcome adjudicators, and the endpoint committee were all masked to treatment assignment. Participants were not masked (you cannot blind people to which diet they're eating), but the people deciding whether an event had occurred were. Endpoint adjudication blinding is the methodologically important piece for a hard-endpoint trial.

The dietary interventions were delivered by a team of dietitians, not by handing out food. The Mediterranean diet group was instructed to consume at least 35% of total energy from fat (22% monounsaturated, primarily from EVOO at minimum 4 tablespoons per day), 14% protein, and less than 50% carbohydrates. The low-fat diet group was instructed to keep total fat below 30% of energy (with less than 10% saturated fat) and to increase complex carbohydrates. Adherence was reinforced through individual visits at 6-month intervals and group sessions every 3 months.

The primary endpoint was a composite of major cardiovascular events: myocardial infarction, revascularization, ischemic stroke, peripheral artery disease, and cardiovascular death. This is a broader composite than PREDIMED used (which counted only MI, stroke, and CV death) because secondary-prevention populations have a wider range of clinically meaningful events.

What They Found

Over a median of 7 years of follow-up, 198 primary endpoint events occurred:

Group	Events / N	Hazard Ratio (95% CI)	Risk Reduction
Mediterranean diet	87 / 502 (17.3%)	0.72 (0.54-0.96)	25-28% lower
Low-fat diet (control)	111 / 500 (22.2%)	1.00 (reference)	--
Men subgroup (Med diet)	67 / 414 (16.2%)	0.67 (0.49-0.92)	33% lower
Men subgroup (low-fat)	94 / 413 (22.8%)	1.00 (reference)	--

Green indicates a favorable direction vs. low-fat diet. Hazard ratios are from the multivariable-adjusted intention-to-treat analysis. The overall and men-subgroup comparisons are statistically significant; 95% confidence intervals exclude 1.0. Log-rank p-value for the overall comparison was 0.039.

The crude event rates were 28.1 per 1,000 person-years in the Mediterranean diet group versus 37.7 per 1,000 person-years in the low-fat group. That's an absolute risk reduction of about 9.6 events per 1,000 patient-years -- a clinically meaningful number on top of guideline-directed medical therapy.

Reading the Results

The Mediterranean-versus-low-fat comparison. CORDIOPREV is one of the few trials that directly pits the Mediterranean diet against the conventional low-fat diet that was U.S. and European dietary guidance for decades. The Mediterranean diet outperformed. The mechanism most consistent with the result is that the Mediterranean pattern -- rich in monounsaturated fat, plant polyphenols, fiber, and seafood -- produces favorable changes in lipid oxidation, endothelial function, and chronic inflammation that the low-fat diet does not match.

The sex-specific finding. The effect was concentrated in men (33% relative risk reduction) and not significant in women. The most likely explanation is statistical power: only 175 women were enrolled, compared to 827 men, so the women's subgroup had limited ability to detect even a real effect. A secondary explanation is biological -- premenopausal estrogen confers cardiovascular protection that may narrow the gap between dietary interventions in younger women, though most participants in this trial were postmenopausal. The paper itself recommends interpreting the women-specific null result with caution given the small sample.

The polyphenol contribution. The Mediterranean diet group consumed at least 4 tablespoons per day of EVOO, which translates to approximately 50 mL/day and a polyphenol load of 250 to 500 mg/day depending on the oil's phenolic concentration. That's well above the EFSA threshold of 5 mg/day of hydroxytyrosol for the authorized health claim on protection of blood lipids from oxidative damage. The biomarker substudies from CORDIOPREV have shown improvements in oxidized LDL, inflammatory markers, and endothelial function in the Mediterranean diet arm -- consistent with the polyphenol mechanism.

What Didn't Change

The primary endpoint comparison was not significant in the 175-woman subgroup, though the direction of effect was the same as in men. The paper attributes this to insufficient statistical power rather than a true null effect.

CORDIOPREV is a single-center trial, which limits external generalizability. The participants were Spanish patients in Cordoba; the dietary pattern is culturally embedded there and easier to adhere to than it might be in populations less accustomed to a Mediterranean food environment. Adherence was reinforced through frequent dietitian visits, which is more intensive than typical clinical practice.

The trial also did not test EVOO as an isolated intervention. It tested the Mediterranean diet pattern that includes EVOO as one component. The Mediterranean diet bundle -- olive oil, fish, vegetables, legumes, whole grains, moderate wine -- is what was randomized, and the bundle is what showed benefit.

Broader Context

CORDIOPREV complements PREDIMED in the way the literature most needed. PREDIMED tested primary prevention -- people at risk but without diagnosed disease -- and found 31% reduction in cardiovascular events. CORDIOPREV tested secondary prevention -- people with established coronary heart disease -- and found 25-28% reduction. The two trials together establish the Mediterranean diet across both ends of the cardiovascular prevention spectrum.

The 2011 European Food Safety Authority opinion (Regulation 432/2012) authorized a health claim for olive oil polyphenols and protection of blood lipids from oxidative damage at 5 mg/day of hydroxytyrosol and derivatives. The mechanistic chain established by EUROLIVE (Covas 2006) -- polyphenols reduce oxidized LDL -- is the most likely biological pathway linking the dietary pattern to the hard cardiovascular endpoints in CORDIOPREV.

Subsequent observational evidence from the Harvard cohorts (Guasch-Ferre 2020 in JACC; Guasch-Ferre 2022 in JACC) has shown similar dose-response patterns in U.S. adults consuming much smaller amounts of olive oil -- benefit emerging at more than 7 grams per day rather than the 50+ grams used in CORDIOPREV. The combined picture: there appears to be a meaningful cardiovascular signal at modest intake, with larger doses (as in CORDIOPREV and PREDIMED) producing larger absolute effects.

Related Research

Continue exploring olive oil and polyphenol science:

• PREDIMED Republished: Mediterranean Diet + EVOO Cut Major CV Events by 30%
• PREDIMED Outcome-Wide: EVOO and Multiple Cardiovascular Endpoints
• Olive Oil and Brain Health: 66% Lower Cognitive Impairment Risk in PREDIMED Trial

Source: View the original study on PubMed

Olivea's Dosage

The CORDIOPREV Mediterranean diet group consumed at least 4 tablespoons (approximately 50 mL) of extra virgin olive oil per day. A single tablespoon of Olivea extra virgin olive oil delivers approximately 14 grams; four tablespoons per day matches the CORDIOPREV protocol. For a concentrated polyphenol dose without the caloric load, each Olivea capsule delivers over 20 mg of hydroxytyrosol per serving in an EVOO matrix; our most recent third-party certificate of analysis confirmed 23.5 mg per capsule.

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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