The Mediterranean diet has been the subject of studies for more than 15 years. The results still hold up today: eating a diet based on fresh fruits, vegetables, whole grains, and heart-healthy omega-3s can help prevent heart disease.
The iconic Lyon Heart Study that took place between 1993 and 1999 was the first clinical trial to demonstrate the ability of a simple dietary pattern to achieve very powerful outcomes: prevention of secondary cardiovascular events in people who had survived a heart attack.
The Mediterranean diet or Mediterranean dietary pattern (MED) is a fruit-and-vegetable-based diet that is rich in whole grains and plant-based omega-3 and omega-9 fatty acids; emphasizes fish and lean meats as protein sources; and is likewise low in red meat, organ meats, saturated fat, trans fat, and cholesterol.
Compared to participants receiving standard care (including pharmacological agents), participants who received standard care plus counselling on the MED achieved a 56 percent reduction in the risk of all-cause death and a 67 percent reduction in the risk of any major coronary event.
Compare these outcomes to those of standard care interventions (pharmacological agents) for secondary coronary prevention:
- 22 percent reduction in risk of all-cause death per 10 beat-per-minute reduction in resting heart rate from beta-blocker medicine administration.
- 12 percent reduction in risk of all-cause death per 1 mmol/L reduction in LDL (bad) cholesterol from statin administration.
- 13 percent reduction in risk of all-cause death through administration of low-dose Aspirin therapy.
What about primary prevention?
In 2013, Spanish researchers conducted a large trial that randomized 7,500 individuals who had no existing heart disease but were considered at high risk for heart disease into one of three groups: MED plus supplemental olive oil, MED plus supplemental mixed nuts, or control (advice to reduce dietary fat). Researchers stopped the trial early, just under five years in, due to the clear and important benefit of the MED.
The primary endpoint was a composite of myocardial infarction, stroke, and death from cardiovascular causes. Compared to control, participants assigned to the MED plus olive oil or MED plus mixed nuts were 30 percent less likely to suffer such an event.
The truly immense magnitude of benefit reproducibly demonstrated by the MED has garnered significant research interest over the past decade and a half. While the seminal research on this dietary pattern for cardiovascular health is more than 15 years old now, there is yet to be a pharmaceutical intervention that compares to adherence to the MED for reduction of risk in settings of secondary coronary prevention or for primary coronary prevention.