Dietary inflammatory index and Mediterranean Diet in female reproductive health: a systematic review and meta-analysis of dietary inflammatory potential.

INTRODUCTION: Female reproductive health is increasingly affected by conditions such as infertility, polycystic ovary syndrome (PCOS), and endometriosis. Given the impact of modifiable lifestyle factors, nutrition has emerged as a potential preventive strategy. The Mediterranean Diet, characterised by high contents of anti-inflammatory and antioxidant compounds, may influence ovarian function, hormonal regulation, and reproductive outcomes. This study aimed to evaluate the association between adherence to the Mediterranean Diet and female reproductive health. METHODOLOGY: A systematic review was conducted according to PRISMA 2020 guidelines and registered in PROSPERO (CRD420261295562). PubMed, Scopus, ScienceDirect, and CINAHL databases were searched. Methodological quality was independently assessed using Joanna Briggs Institute critical appraisal tools. A meta-analysis of odds ratios was performed using the inverse variance method, and heterogeneity was assessed using Cochran's Q and I 2 statistics. RESULTS: Fifteen unique studies were included in the systematic review and qualitative synthesis, of which two were eligible for quantitative meta-analysis. Higher dietary inflammatory potential, assessed by the Dietary Inflammatory Index (DII), was associated with an increased risk of female infertility (OR = 1.70; 95% CI: 1.23-2.34; p = 0.0013), with no observed heterogeneity (I 2 = 0%). Qualitative evidence suggested that greater adherence to the Mediterranean Diet was associated with higher anti-Müllerian hormone levels, increased antral follicle counts, reduced risk of poor ovarian response (OR = 0.29), lower likelihood of endometriosis (OR = 0.06), fewer premenstrual symptoms, and improved blastocyst formation rates in assisted reproduction. DISCUSSION: These findings support the potential role of anti-inflammatory dietary patterns in female reproductive health. Mediterranean Diet components, including omega-3 fatty acids, polyphenols, and monounsaturated fats, may reduce oxidative stress, improve insulin sensitivity, and modulate endocrine pathways. However, the certainty of evidence was rated as very low due to the predominance of observational studies. CONCLUSION: Observational evidence suggests that lower dietary inflammatory potential and greater adherence to the Mediterranean Diet are inversely associated with female infertility and adverse reproductive markers. However, because current evidence is overwhelmingly observational, these findings represent clinical associations rather than proven causal or therapeutic effects, highlighting the need for randomized controlled trials before clinical implementation. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420261295562, CRD420261295562.