"Mediterranean Diet for Primary Prevention of Cardiovascular Disease". The New England Journal of Medicine. 2013. Full text•PDF

Contents

1 Clinical Question
2 Bottom Line
3 Major Points
4 Guidelines
5 Design
6 Population
6.1 Inclusion Criteria
6.2 Exclusion Criteria
6.3 Baseline Characteristics
7 Interventions
8 Outcomes
8.1 Primary Outcome
8.2 Secondary Outcomes
9 Criticisms
10 Funding
11 Further Reading

Clinical Question

In patients at high cardiovascular risk but with no cardiovascular disease at enrollment, does a Mediterranean diet supplemented with extra-virgin olive oil or mixed nuts reduce the incidence of major cardiovascular events?

Bottom Line

Among high-risk patients, a Mediterranean diet supplemented with extra-virgin olive oil or mixed nuts resulted in a significant reduction in the risk of major cardiovascular events, supporting its use for the primary prevention of cardiovascular disease.

Major Points

Guidelines

Current findings support the benefits of the Mediterranean diet in reducing cardiovascular risk and are in line with dietary recommendations promoting its adoption for overall health improvement.

Design

- Multicenter, randomized, controlled trial
- N=7,447 participants at high cardiovascular risk
- Mediterranean diet supplemented with extra-virgin olive oil, mixed nuts, or control diet (advice to reduce dietary fat)
- Median follow-up: 4.8 years
- The trial was stopped early due to the demonstrated benefits of the Mediterranean diet

Population

- High-risk individuals aged 55 to 80 years without cardiovascular disease
- Inclusion criteria: Type 2 diabetes mellitus or ≥3 major risk factors such as smoking, hypertension, elevated LDL cholesterol, etc.
- Baseline characteristics: balanced across the three study groups

Interventions

- Mediterranean diet with extra-virgin olive oil (~1 liter/week)
- Mediterranean diet with mixed nuts (30g/day)
- Control diet with advice to reduce dietary fat
- All groups received quarterly educational sessions; the Mediterranean groups received supplemental foods, and the control group received small nonfood gifts

Outcomes

Primary Outcome
- Rate of major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes):
- Group with extra-virgin olive oil: 3.8%, HR 0.70 (95% CI, 0.53 to 0.91)
- Group with mixed nuts: 3.4%, HR 0.70 (95% CI, 0.53 to 0.94)
- Control group: 4.4%

Secondary Outcomes
- Stroke, myocardial infarction individually, death from cardiovascular causes, and death from any cause

Criticisms

- Findings mostly reflect the benefits of supplemental foods (olive oil, nuts)
- Dropout rates were higher in the control group
- Study's generalizability might be limited to high-risk Mediterranean populations

Funding

Supported by the Spanish government's Instituto de Salud Carlos III and others; food donors included extra-virgin olive oil and nut producers. The sponsors had no role in the trial design, data analysis, or reporting.

Further Reading

For additional details, the full study can be found in The New England Journal of Medicine, published in 2013. Further information on disclosures, protocols, and author affiliations is available with the article.