RESUMO
The Mediterranean Diet, characterized by high consumption of plant-based foods, olive oil, moderate intake of fish and poultry, and low consumption of red meat and processed foods, has been suggested to improve assisted reproductive technology (ART) outcomes. This narrative review aimed to summarize and synthesize the evidence from observational studies on the associations between preconception adherence to the Mediterranean Diet and ART outcomes. PubMed/MEDLINE, Embase, ScienceDirect, Google Scholar, and Web of Science databases were searched to identify relevant studies. Seven observational studies (n = 2321 women undergoing ART) were included. Adherence to the Mediterranean Diet was assessed using food frequency questionnaires with 6-195 items. Three studies found that higher Mediterranean Diet scores were associated with improved clinical pregnancy rates (OR 1.4, 95% CI 1.0-1.9; RR 1.98, 95% CI 1.05-3.78) or live birth rates (RR 2.64, 95% CI 1.37-5.07). Two studies showed a positive effect on embryo yield (p = 0.028) and ovarian response. However, two studies reported no significant associations with ultimate ART success, and four studies found no effects on oocyte and embryo number or quality. The heterogeneity in study designs, Mediterranean Diet assessment methods, and ART protocols limited the strength of conclusions. Evidence for the effects of greater adherence to the Mediterranean Diet on ART outcomes is limited but promising. Future research should focus on conducting randomized controlled trials with standardized Mediterranean Diet assessment methods to establish causal relationships between Mediterranean Diet adherence and ART outcomes, and to elucidate potential mechanisms of action.