Effect of the Mediterranean Diet Supplemented With Olive Oil Versus the Low-Fat Diet on Serum Inflammatory and Endothelial Indexes Among Adults: A Systematic Review and Meta-analysis of Clinical Controlled Trials

Nutr Rev. 2025 Jul 1;83(7):e1421-e1440. doi: 10.1093/nutrit/nuae166.

Abstract

Context: Inflammation and endothelial dysfunction are important risk factors for chronic diseases, including cardiovascular diseases and related mortality.

Objective: This systematic review and meta-analysis aimed to assess the effects of 2 popular dietary patterns-a Mediterranean (MED) diet supplemented with olive oil and a low-fat diet (LFD)-on factors related to inflammation and endothelial function in adults.

Data sources and data extraction: The following online databases were searched for related studies published until August 7, 2024: PubMed/Medline, Scopus, Clarivate Analytics Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar. Two independent researchers selected the studies based on the eligibility criteria.

Data analysis: The effect sizes were expressed as Hedges' g with 95% CIs. A total of 16 eligible trials with 20 effect sizes were included in the analyses. This meta-analysis revealed that the MED diet supplemented with olive oil significantly improved all of the indicators of the study compared with the LFD, except in the case of E-selectin, in which a low and nonsignificant decrease was reported.

Conclusion: Available evidence suggests that a MED diet supplemented with olive oil compared with the LFD significantly improves inflammation and serum endothelial function in adults.

Systematic review registration: PROSPERO registration no. CRD42023485718.

Keywords: Mediterranean diet; endothelial function; inflammation; low-fat diet; meta-analysis; olive oil.

Plain language summary

In this meta-analysis, the effects of a Mediterranean (MED) diet supplemented with olive oil versus a low-fat diet (LFD) on serum inflammatory and endothelial factors were reviewed. According to the findings of this study, the MED diet rich in olive oil significantly reduces serum C-reactive protein (CRP), high-sensitivity CRP (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), P-selectin, and monocyte chemoattractant protein 1 (MCP-1) levels compared with the LFD. It is worth noting that the effect size was small for TNF-α and VCAM-1.The MED diet supplemented with olive oil also increases flow-mediated dilation compared with the LFD.

Publication types

  • Systematic Review
  • Meta-Analysis

MeSH terms

  • Adult
  • Controlled Clinical Trials as Topic
  • Diet, Fat-Restricted* / methods
  • Diet, Mediterranean*
  • Dietary Supplements
  • Endothelium, Vascular*
  • Female
  • Humans
  • Inflammation* / blood
  • Inflammation* / diet therapy
  • Male
  • Middle Aged
  • Olive Oil* / administration & dosage

Substances

  • Olive Oil