The Mediterranean diet and heart disease
In the PREDIMED trial, a Mediterranean dietary pattern supplemented with extra-virgin olive oil or nuts was associated with fewer major cardiovascular events than a control diet.
What the study found
PREDIMED (New England Journal of Medicine; original 2013, republished with corrected randomization in 2018) assigned adults at high cardiovascular risk to one of three eating patterns: a Mediterranean diet supplemented with extra-virgin olive oil, the same diet supplemented with mixed nuts, or a control diet advised to reduce fat. Over roughly five years, the two Mediterranean-diet groups had fewer major cardiovascular events — a combination of heart attack, stroke, and cardiovascular death — than the control group. This reports what the trial observed; it is not dietary advice.
Why it matters
Much nutrition evidence comes from observational studies that can only show association. PREDIMED was a large randomized trial testing an entire dietary pattern, rather than a single nutrient, against hard clinical outcomes — a stronger design for asking whether how people eat changes cardiovascular risk.
Analysis — the pattern
This supports a broader shift (analysis, not a single-study claim): nutrition science increasingly studies whole dietary patterns instead of isolated nutrients, since foods are eaten in combination and single-nutrient trials have often disappointed. After a data error prompted reanalysis, the main finding held, which itself illustrates how the field self-corrects.
What is still uncertain
Participants were a specific high-risk Mediterranean population, so results may not transfer identically elsewhere. Diet trials are hard to blind and rely on self-reported adherence, and exactly which components drive the benefit — olive oil, nuts, or the overall pattern — remains debated.