Evaluation of the effect of mediterranean diet on serum zonulin levels and treatment success in women treated for infertility

We aimed to evaluate the effect of Mediterranean diet on infertility treatment success (number of eggs collected, number of embryos formed, transfer status, clinical pregnancy) and serum zonulin levels. The study was conducted between February and July 2024 with 43 female individuals (22 intervention and 21 control) with a body mass index (BMI) of 18.5-29.9 kg/m2 who applied to a fertility center in Ankara for infertility treatment. The questionnaire form prepared by the researcher was completed by using the face-to-face interview method. The questionnaire included questions to determine the socio-demographic characteristics, infertility history and dietary habits of the individuals. IPAQ was used to determine physical activity status. The women in the intervention group were prepared an 8-week nutrition program compatible with the Mediterranean diet, in accordance with their daily energy requirements, and nutrition education on the Mediterranean diet was given. The Mediterranean Diet Adherence Scale (MEDAS) was administered at the beginning of the study and at the end of the 8th week to determine the adherence of the individuals in the intervention group to the Mediterranean diet and three-day food consumption records were taken. To measure zonulin concentrations in serum, commercially available enzyme-linked immunosorbent assay (ELISA) kits were used and evaluated twice in both groups. At the end of the study, the decrease in the mean BMI in the intervention group was statistically significant (p<0.05). The change in the mean MEDAS score after the intervention was statistically significant (p<0.05). In addition, baseline MEDAS scores of women who were transferred were found to be higher (p<0.05). At the beginning of the study, the mean zonulin was 4.3±3.96, 4.2±3.25, and 2.6±0.74 for women who were low, medium, and high compliant with the Mediterranean diet, respectively, whereas at the end of the study, there were no women who were low, medium, and high compliant with the Mediterranean diet, respectively, and the mean zonulin was 3.2±0.89 and 3.6±1.79, respectively (p<0.05). There was a moderate negative correlation (r=-0.270, p=0.048) between baseline MEDAS mean and baseline Zonulin value. In the intervention group, the mean baseline MEDAS score of those with a positive pregnancy result was higher than those with a negative pregnancy result (p<0.05). In both intervention and control groups, the mean baseline Zonulin scores of those with positive pregnancy results were lower than those with negative pregnancy results (p<0.05). As adherence to the Mediterranean diet increases, favorable results may be achieved in parameters related to intestinal permeability. Positive clinical pregnancy was associated with low zonulin levels. It is thought that restoration of intestinal permeability may contribute to increase the treatment success of infertile women. However, larger studies with a larger sample size are needed.