The Effect of Nutrients and Dietary Supplements on Sperm Quality Parameters: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized clinical trials
PubMed 30462179 · doi:10.1093/advances/nmy057
What was done
A systematic review and meta-analysis of randomized clinical trials from the MEDLINE-PubMed database was conducted to assess the effect of nutrients, dietary supplements, or food on sperm quality parameters. A total of 28 articles met inclusion criteria for qualitative review, and 15 provided data for quantitative meta-analysis (PROSPERO CRD42017058380).
What was found
Sperm concentration (mean difference [MD]; 95% CI, 10^6 spermatozoa/mL) significantly increased with omega-3 fatty acids (10.98; 10.25 to 11.72), CoQ10 (5.93; 5.36 to 6.51), selenium (3.91; 3.08 to 4.73), and zinc (1.48; 0.69 to 2.27). Total sperm count (MD, 10^6 spermatozoa/mL) increased with omega-3 fatty acids (18.70; 16.89 to 20.51) and CoQ10 (10.15; 8.34 to 11.97). Total sperm motility (%) increased with carnitines (7.84%; 6.54% to 9.13%), omega-3 fatty acids (7.55%; 7.09% to 8.01%), zinc (7.03%; 6.03% to 8.03%), CoQ10 (5.30%; 4.98% to 5.62%), and selenium (3.30%; 2.95% to 3.65%). Progressive motility increased only with carnitines (7.45%; 6.24% to 8.67%). Sperm morphology (%) improved with carnitines (4.91%), selenium (1.87%), CoQ10 (1.06%), and omega-3 fatty acids (0.91%).
Why it matters
This review synthesizes randomized trial evidence showing that select micronutrients and fatty acids can improve surrogate semen quality metrics, identifying specific candidate supplements for male subfertility evaluation.
Limits
The search was restricted to a single database (MEDLINE-PubMed). The included randomized trials had small sample sizes, considerable interstudy heterogeneity was present, and clinical outcomes such as pregnancy and live birth rates were not reported.