Mediterranean diet and blood pressure reduction in adults with and without hypertension: A systematic review and meta-analysis of randomized controlled trials

Christina D Filippou; Costas G Thomopoulos; Maria M Kouremeti; Lida I Sotiropoulou; Petros I Nihoyannopoulos; Dimitrios M Tousoulis; Costas P Tsioufis

doi:10.1016/j.clnu.2021.01.030

Mediterranean diet and blood pressure reduction in adults with and without hypertension: A systematic review and meta-analysis of randomized controlled trials

Clin Nutr. 2021 May;40(5):3191-3200. doi: 10.1016/j.clnu.2021.01.030. Epub 2021 Jan 29.

Authors

Christina D Filippou¹, Costas G Thomopoulos², Maria M Kouremeti¹, Lida I Sotiropoulou¹, Petros I Nihoyannopoulos¹, Dimitrios M Tousoulis¹, Costas P Tsioufis³

Affiliations

¹ First Cardiology Clinic, Medical School, National and Kapodistrian University of Athens, Hippokration Hospital, Athens, Greece.
² Department of Cardiology, Helena Venizelou Hospital, Athens, Greece.
³ First Cardiology Clinic, Medical School, National and Kapodistrian University of Athens, Hippokration Hospital, Athens, Greece. Electronic address: ktsioufis@hippocratio.gr.

PMID: 33581952
DOI: 10.1016/j.clnu.2021.01.030

Abstract

Background & aims: It is unclear whether the Mediterranean diet (MedDiet) has a favorable effect on blood pressure (BP) levels because among randomized controlled trials (RCTs) investigating the MedDiet-mediated BP reduction significant methodological and clinical differences are observed. The purpose of this study was to comprehensively assess the MedDiet BP-effect compared to the usual diet or another dietary intervention (e.g. low-fat diet) in adults with and without hypertension, accounting for methodological and clinical confounders.

Methods: We systematically searched Medline and the Cochrane Collaboration Library databases and identified 35 RCTs (13,943 participants). Random-effects model was used to calculate the mean attained systolic BP (SBP) and diastolic BP (DBP) differences during follow-up. Subgroup and meta-regression analyses were also conducted.

Results: Compared to the usual diet and all other active intervention diets the MedDiet reduced SBP and DBP (difference in means: -1.5 mm Hg; 95% CI: -2.8, -0.1; P = 0.035, and -0.9 mm Hg; 95% CI: -1.5, -0.3; P = 0.002, respectively). Compared only to the usual diet the MedDiet reduced SBP and DBP, while compared to all other active intervention diets or only to the low-fat diet the MedDiet did not reduce SBP and DBP. The MedDiet reduced DBP levels to a higher extent in trials with mean baseline SBP ≥130 mm Hg, while both SBP and DBP were reduced more in trials with a mean follow-up period ≥16 weeks. The quality of evidence was rated as moderate for both outcomes according to the grading of recommendations, assessment, development and evaluation (GRADE) approach.

Conclusions: The adoption of the MedDiet was accompanied by a relatively small, but yet significant BP reduction, while higher baseline SBP levels and longer follow-up duration enhanced the BP-lowering effect of the intervention. This meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO) as CRD42020167308.

Registry number: CRD42020167308.

Keywords: Blood pressure; Diet; Mediterranean; Meta-Analysis; Randomized controlled trials; Systematic review.

Publication types

Meta-Analysis
Systematic Review

MeSH terms

Blood Pressure / physiology*
Diet, Mediterranean / statistics & numerical data*
Humans
Hypertension / diet therapy*
Hypertension / physiopathology
Randomized Controlled Trials as Topic