Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease

The Mediterranean diet enjoys near-universal endorsement. This Cochrane review applies the cold standard of randomized trials and finds the picture more uncertain than the reputation suggests.

Across 30 trials and over 12,000 participants, the evidence was of low-to-moderate quality and inconsistent. The clearest signal was a possible reduction in stroke, alongside small improvements in blood pressure and LDL cholesterol. But for the hardest endpoints — total mortality and heart attack — the review found little or no demonstrated effect, and trial quality limited confidence throughout.

The practical takeaway is calibrated enthusiasm: a Mediterranean-style diet rich in olive oil, nuts, fruits, and vegetables is reasonable and may help with stroke and risk factors, but the randomized evidence for preventing death or heart attack is weaker than the popular consensus implies. The resistance, interestingly, may come from diet partisans of all stripes unhappy with “uncertain.”

We rate the evidence moderate: rigorous Cochrane methodology, but applied to a body of trials with heterogeneity and bias that the authors flag honestly. Its clinical significance is moderate — real, if modest, benefits on some risk factors, against genuine uncertainty about hard outcomes. A useful reminder that even a “consensus” diet rests on shakier randomized ground than assumed.