Mediterranean Diet Adherence, Fatty Acid Profiles, and Early Assisted Reproduction Outcomes: Findings from a 12-Week Dietary Intervention

<i>Background and Objectives</i>: Evidence on the impact of adherence to the Mediterranean diet alone-without supplementation-on serum and follicular fluid fatty acid profiles and assisted reproduction outcomes remains limited. This study evaluated the effects of a pre-treatment Mediterranean diet intervention on these parameters. <i>Materials and Methods:</i> In this prospective, non-randomized controlled trial, 32 women undergoing infertility treatment were allocated to a Mediterranean diet intervention group (<i>n</i> = 16) or a control group (<i>n</i> = 16). The intervention lasted 12 weeks, and adherence was assessed using validated dietary indices. Serum and follicular fluid fatty acid profiles were analyzed, and implantation and pregnancy outcomes were recorded. <i>Results:</i> The diet group showed increased ω-6 and ω-3 intake with decreased LA/ALA and ω-6/ω-3 ratios. In the control group, serum EPA + DHA levels declined, whereas in the diet group serum LA/ALA decreased. Follicular fluid in the intervention group had lower EPA + DHA and ω-6 ratios. Diet adherence correlated positively with MII oocytes (r = 0.797) and pronuclei (r = 0.741). No significant associations were found between follicular fluid fatty acids and IVF outcomes. A total of four implantation events were observed (intervention: <i>n</i> = 3; control: <i>n</i> = 1). Two of the implantations in the intervention group resulted in live births, while the remaining implantation events did not result in live birth. <i>Conclusions:</i> A Mediterranean diet-aligned dietary intervention may induce favorable changes in blood and follicular fluid parameters; however, the underlying metabolic mechanisms warrant further investigation. Three implantations were observed in the intervention group and one in the control group; given the low number of events, comparisons of live birth outcomes should be interpreted with caution. Overall, the findings regarding ART outcomes and clinical translation remain exploratory due to the limited sample size. Well-designed randomized controlled trials in which ART and clinical endpoints are defined as primary outcomes are needed.