Association between the adherence to different dietary patterns and sperm chromatin integrity in healthy men

Abstract

Research question: Are healthy and unhealthy diets associated with sperm DNA fragmentation and chromatin deprotamination in healthy men of reproductive age?

Design: A cross-sectional analysis conducted using healthy male volunteers (n = 200), aged 18-40 years, participating in the Led-Fertyl study. Adherence to five dietary patterns were estimated using a-priori indices: Mediterranean diet (Mediterranean Diet Adherence Screener; [MEDAS]); healthy and unhealthy plant-based diets; EAT-Lancet diet and Western diet. Dietary intake was assessed using a validated 143-item Food Frequency Questionnaire. Double-strand DNA fragmentation in spermatozoa evaluated by the Neutral Comet assay and chromatin deprotamination evaluated through chromomycin A3 (CMA3) staining by flow cytometry, were considered the main outcomes.

Results: No association between adherence to MEDAS, healthy and unhealthy plant-based, EAT-Lancet or Western dietary patterns with sperm DNA fragmentation was observed. Furthermore, adherence to MEDAS, healthy plant-based, EAT-Lancet or Western dietary patterns did not differ in sperm chromatin deprotamination. Yet, adherence to the unhealthy plant-based diet was non-linearly associated with increased chromatin deprotamination in all statistical models. Compared with the lowest tertile, participants in the highest unhealthy plant-based tertile had greater sperm chromatin deprotamination (β = 12.4, 95% CI 2.7 to 22.1, P = 0.026), suggesting a higher occurrence of abnormalities in sperm chromatin condensation.

Conclusion: To the best of our knowledge, this study is the first to epidemiologically investigate the relationship between dietary patterns and sperm chromatin integrity, highlighting that adherence to unhealthy plant-based diets may lead to sperm chromatin abnormalities. These findings underscore the potential effect of specific dietary patterns on molecular sperm quality parameters and support further research into dietary strategies for optimizing sperm integrity and improving male fertility.

Keywords: DNA fragmentation; Dietary patterns; Male fertility; Plant-based diet; Sperm chromatin integrity.