The Potential Role of the Mediterranean Diet on Clinical Outcomes in Patients with Inflammatory Bowel Disease: A Systematic Review

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• Picked for Biochemistry (medical) (top studies of the week, 26 July 2026).

Abstract

BACKGROUND AND AIMS: The Mediterranean diet (MedDiet), a plant-based diet that primarily relies on vegetables, fruits, and fiber, has been suggested to modulate the gut microbiota and improve quality of life (QoL), particularly in patients with inflammatory bowel diseases (IBDs). This study aimed to review and evaluate the impact of adherence to the MedDiet in patients with IBDs. METHODS: The following Databases were systematically searched from inception to May 2025: PubMed, EMBASE, Scopus, and Web of Science (WOS) to identify studies that met our eligibility criteria. Randomized controlled trials and observational studies evaluating the MedDiet in adults with ulcerative colitis or Crohn's disease and reporting clinical, inflammatory, or quality-of-life outcomes were included, while pediatric, animal, and non-MedDiet studies were excluded; study quality was assessed using RoB 2 for randomized trials, ROBINS-I for observational studies, and a modified Newcastle-Ottawa Scale for cross-sectional studies. The protocol was registered on PROSPERO: (CRD420251053638). RESULTS: A total of 12 studies were included in this review, involving 1,615 patients. Four studies were interventional (three randomized controlled trials (RCTs) and one single-arm trial. The remaining eight studies were observational with varying designs (four cohort, three cross-sectional, and one case-control). These studies examined the relationship between adherence to the MedDiet and various clinical outcomes, including C-reactive protein (CRP) levels, QoL, and disease severity. Overall, observational studies suggested beneficial associations between greater MedDiet adherence and lower inflammatory markers, improved quality of life, and reduced disease activity. In contrast, randomized controlled trials showed mixed, generally non-significant effects on inflammatory biomarkers. CONCLUSIONS: Adherence to the MedDiet may enhance QoL and support remission. However, the findings should be interpreted with caution due to substantial heterogeneity in study designs, populations, outcome measures, and risk of bias, which precluded meta-analysis and limited the strength of the evidence. There is a strong need for well-designed, large-scale RCTs to further investigate MedDiet's impact on clinical outcomes in IBD patients and to identify specific nutritional components that can be applied to patients who cannot tolerate certain dietary components.

Abstract as published, via PubMed.