Relationship between dietary glycemic index and glycemic load and sperm-quality parameters in Iranian men: a cross-sectional study

Background: Infertility is a major clinical problem with psychological, financial and medical costs. Male infertility has recently been linked to 50% of childless couples. It is worth mentioning that diet and its components can be manipulated and applied in counseling meetings of infertile men as a modifiable factor. The goal of this study was to determine the correlation of dietary glycemic index (GI) and glycemic load (GL) with sperm-quality parameters in Iranian men. Materials and methods: In this cross-sectional study which was carried from Aug to Nov 2023, after excluding smokers, 322 men who were attending the IVF clinic of Ayatollah Mousavi Hospital for seminal analysis were enrolled. Dietary intake was completed by an expert dietitian through face-to-face interviews with a validated 168-item food frequency questionnaire (FFQ). In the present study, sperm-quality parameters, including motility, concentration, normal morphology, vitality, DNA fragmentation index (DFI), and chromatin maturation of sperm, were analyzed. The relationship between dietary GI and CL and these parameters was assessed. Results: Adjusting for the baseline variables, dietary GI and GL showed positive and negative associations with sperm progressive motility, respectively (p = 0.01 and p < 0.001). Higher dietary GI was associated with lower (p = 0.03); however, a higher dietary GL was associated with higher immotile sperm (p < 0.001). A higher dietary GI was associated with a 77% higher sperm count (p = 0.003). In contrast, higher dietary GL was associated with a lower count (p < 0.001). Higher dietary GI and GL were associated with higher and lower percentages of sperm with normal morphology by 70% and 40%, respectively (p < 0.001 in both). A higher dietary GL was associated with an increase in sperm vitality and DFI of 33% and 53%, respectively (p < 0.001). Higher dietary GI showed a significant negative effect on sperm DFI (p = 0.009). Dietary GI and GL showed significant positive and negative effects on SCMA, respectively (p = 0.002 and p < 0.001). Conclusion: A diet with a higher GI showed beneficial effects on more parameters of sperm; however, higher dietary GL showed deleterious effects, except sperm vitality and SCMA. More studies are needed to obtain a concise result.