Effects of the Mediterranean Diet on Cardiovascular Outcomes-A Systematic Review and Meta-Analysis

PLoS One. 2016 Aug 10;11(8):e0159252. doi: 10.1371/journal.pone.0159252. eCollection 2016.

Abstract

Background: A Mediterranean dietary pattern is widely recommended for the prevention of chronic disease. We sought to define the most likely effects of the Mediterranean diet on vascular disease and mortality.

Methods: We searched MEDLINE, EMBASE and the Cochrane Central Register without language restriction for randomized controlled trials comparing Mediterranean to control diets. Data on study design, patient characteristics, interventions, follow-up duration, outcomes and adverse events were sought. Individual study relative risks (RR) were pooled to create summary estimates.

Results: Six studies with a total of 10950 participants were included. Effects on major vascular events (n = 477), death (n = 693) and vascular deaths (n = 315) were reported for 3, 5 and 4 studies respectively. For one large study (n = 1000) there were serious concerns about the integrity of the data. When data for all studies were combined there was evidence of protection against major vascular events (RR 0.63, 95% confidence interval 0.53-0.75), coronary events (0.65, 0.50-0.85), stroke (0.65, 0.48-0.88) and heart failure (0.30, 0.17-0.56) but not for all-cause mortality (1.00, 0.86-1.15) or cardiovascular mortality (0.90, 0.72-1.11). After the study of concern was excluded the benefit for vascular events (0.69, 0.55-0.86) and stroke (0.66, 0.48-0.92) persisted but apparently positive findings for coronary events (0.73, 0.51-1.05) and heart failure (0.25, 0.05-1.17) disappeared.

Conclusion: The Mediterranean diet may protect against vascular disease. However, both the quantity and quality of the available evidence is limited and highly variable. Results must be interpreted with caution.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Cardiovascular Diseases / mortality*
  • Cardiovascular Diseases / prevention & control*
  • Databases, Factual
  • Diet, Mediterranean*
  • Heart Failure / mortality
  • Heart Failure / prevention & control
  • Humans
  • Risk
  • Stroke / mortality
  • Stroke / prevention & control

Grant support

Thaminda Liyanage was supported by an Australian Postgraduate Award and Vlado Perkovic was supported by a National Health and Medical Research Council of Australia (NHMRC) Senior Research Fellowship. Min Jun was supported by postdoctoral fellowships from the Canadian Institutes of Health Research and Alberta Innovates Health Solutions, and an NHMRC early career fellowship. Bruce Neal was supported by an Australian Research Council Future Fellowship and a NHMRC senior research fellowship. Meg Jardine was supported by a Career Development Fellowship from the NHMRC and the National Heart Foundation. This study was supported by the National Health and Medical Research Council (NHMRC) of Australia Program Grant. However, the funding body had no role in study design, data collection and analysis, interpretation or manuscript preparation.