Study question: Are there any associations of dietary patterns with semen quality, reproductive hormone levels, and testicular volume, as markers of testicular function?
Summary answer: These results suggest that traditional Mediterranean diets may have a positive impact on male reproductive potential.
What is known already: The Mediterranean diet has been related to lower risk of multiple chronic diseases, but its effects on reproduction potential are unclear.
Study design, size, duration: Cross-sectional sample of 215 male university students recruited from October 2010 to November 2011 in Murcia Region (Spain).
Participants/materials, setting, methods: Two hundred and nine healthy men aged 18-23 years were finally included in this analysis. Diet was assessed using a validated food frequency questionnaire, and dietary patterns were identified by factor analysis. Linear regression was used to analyze the relation between diet patterns with semen quality parameters, reproductive hormone levels and testicular volume adjusting for potential confounders.
Main results and the role of chance: We identified two dietary patterns: a Mediterranean (characterized by high intakes of vegetables, fruits and seafood) and a Western pattern (characterized by high intakes of processed meats, French fries and snacks). The Mediterranean pattern was positively associated with total sperm count (P, trend = 0.04). The Western pattern was positively related to the percentage of morphologically normal sperm (P, trend = 0.008). We found an inverse association between adherence to the Western pattern and sperm concentration among overweight or obese men (P, trend = 0.04).
Limitations, reasons for caution: As with all cross-sectional studies, causal inference is limited. However, participants were blinded to the study outcomes thus reducing the potential influenced their report of diet. Although we adjusted for a large number of known and suspected confounders, we cannot exclude the possibility of residual confounding or chance findings.
Wider implications of the findings: This study was carried out on healthy and young men, so it is difficult to predict whether and how the observed differences in semen quality translate into reproductive success for men in couples trying to conceive. These results suggest that traditional Mediterranean diets may have a positive impact on male reproductive potential.
Keywords: Mediterranean pattern; Western pattern; diet; male reproductive health; male reproductive hormones; semen quality.
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