The Effect of a Mediterranean Diet on Arterial Stiffness: A Systematic Review

Background: The Mediterranean diet has long been associated with better cardiovascular health, with evidence suggesting that it may play a key role in reducing arterial stiffness. This research aims to systematically review existing evidence on the association between a Mediterranean diet pattern and arterial stiffness in the general population. Methods: The literature was examined in six electronic databases up until December 2024. The evaluation of the 128 publications based on inclusion criteria resulted in the selection of 16 observational and randomized controlled trials that aligned with the research question. Two researchers simultaneously extracted the data, employing inter-rater reliability (IRR) to assess coder agreement, followed by the κ statistic to evaluate accuracy and precision. According to the PRISMA principles and quality evaluation procedures, all data extraction phases achieved a k coefficient of no less than 0.9. All publications, with the exception of randomized controlled trials (RCTs), were evaluated for bias risk utilizing the NIH Quality Assessment Toolkit. The study protocol was registered with PROSPERO (CRD42024597173). Results: Most studies were observational (ten cross-sectional, three longitudinal), with three RCTs. Studies were primarily conducted in Europe (82%), followed by America (12%) and Australia (6%), with a total of 13,680 participants. The evidence showed an inverse relationship between adherence to the Mediterranean diet and arterial stiffness, with a focus on pulse wave velocity (PWV) and the Augmentation Index (AIx) as outcome measures. Lower but consistent and statistically significant evidence was also found in the cross-tabulation of adherence to the Mediterranean diet and the cardiovascular ankle index (CAVI), a proxy of the overall stiffness of the artery from the origin of the aorta to the ankle. Study quality ranged from moderate to high. Conclusions: The available evidence consistently shows that people who follow a Mediterranean diet may have less stiff arteries and, therefore, a lower cardiovascular risk. However, multifactorial biological pathways still need to be corroborated.