A recent systematic review, as detailed in the journal Frontiers in Nutrition, conducted by researchers from Spain has shed light on the potential impact of the Mediterranean diet on the quality of semen in men of reproductive age. The study suggests that adherence to the Mediterranean diet could potentially contribute to improved male reproductive health by positively influencing semen quality.
Background:
Infertility has emerged as a significant concern globally, affecting approximately 15% of the world’s population, which includes around 70 million couples of reproductive age. Contrary to previous assumptions, the World Health Organization’s investigation across 25 nations revealed that male factors contribute to nearly half of infertility cases. The primary causes of male infertility include impaired spermatogenesis, idiopathic factors, endocrine disorders, and altered sperm motility. Clinical assessment of male infertility involves a thorough examination, including medical history, physical examination, and semen analysis. Additionally, factors such as genetics, age, diet, and lifestyle are known to impact male fertility.
The Mediterranean diet, renowned for its potential health benefits, has been associated with positive effects on male reproductive health, including improved semen quality attributed to its anti-inflammatory and antioxidant properties. Evidence suggests that optimal adherence to this dietary pattern may mitigate the risk of various chronic diseases and potentially enhance male fertility by addressing metabolic factors affecting sperm function. Consequently, researchers conducted a systematic review to explore the relationship between the Mediterranean diet and semen quality in men of reproductive age.
About the Study:
The researchers conducted electronic searches in PubMed, the Cochrane Library, Scopus, and Web of Science, in addition to reviewing reference lists, to collect relevant data. Inclusion criteria encompassed open-access articles published in English or Spanish between 2012 and 2022, focusing on men aged 18 to 55. Ten studies met the inclusion criteria, comprising a total of 2,032 participants from various countries, primarily Spain. Study designs included cross-sectional, cohort, case-control, and randomized controlled trials. Data extraction focused on variables such as nutrition status, diet, and semen quality assessment techniques.
The quality of included studies was evaluated using established tools such as the Crombie criteria, the Newcastle-Ottawa Scale, and the PEDro scale, with interrater reliability assessed using Cohen’s kappa statistic. Nutrition status was evaluated based on weight, height, body mass index (BMI), and waist circumference, while adherence to the Mediterranean diet was assessed using validated food frequency questionnaires or specific scores. Semen quality was primarily assessed through parameters such as sperm concentration, motility, morphology, volume, total antioxidant capacity, and hormone levels. Additional factors explored in some studies included chromosome stability, DNA fragmentation, global sperm DNA methylation, microRNA expression, and reactive oxygen species.
Results and Discussion:
Out of the ten studies reviewed, six demonstrated a positive association between semen quality and adherence to the Mediterranean diet, particularly regarding sperm concentration, motility, and total sperm count. Three of these studies reported significantly higher semen quality among men with higher adherence levels to the Mediterranean diet. However, two studies found no significant association between adherence to the Mediterranean diet and semen quality.
While the present study provides valuable insights into the potential benefits of the Mediterranean diet on semen quality, it is constrained by its small sample size, observational design, and limited generalizability. The quality of evidence was rated as very low to moderate using the GRADE system, indicating the need for further research, particularly randomized controlled trials with larger sample sizes, to validate these findings.
Conclusion:
In conclusion, the findings suggest that adopting healthy dietary habits, particularly adherence to the Mediterranean diet, may be associated with improved semen quality in men of reproductive age. The Mediterranean diet, rich in polyunsaturated fatty acids, antioxidants, and anti-inflammatory substances, may help mitigate oxidative stress and its adverse effects on sperm. These findings underscore the importance of dietary counseling for couples planning a pregnancy or undergoing assisted reproductive technology. Nevertheless, further research is warranted to elucidate the intricate relationship between diet and semen quality, thereby informing strategies for promoting fertility and overall health outcomes.