OBJECTIVE: To examine the association of sperm fatty acid composition with sperm concentration.
DESIGN: Cross sectional study.
MATERIALS AND METHODS: We obtained 65 discard semen samples from 33 men undergoing fertility evaluation in an academic medical center. Semen was centrifuged to separate sperm cells from seminal plasma. Levels of specific fatty acids in sperm were measured with gas chromatography and expressed as percentage of total fatty acids. Spearman correlation coefficients between the median level for each man of specific sperm fatty acids and sperm concentration were calculated.
RESULTS: Sperm concentration ranged from 0.01x10/mL to 400 x10/mL (median = 14x10/mL). Peaks for all major fatty acids, including trans fats, could be clearly identified in all samples. The average fatty acid composition of sperm was 64% saturated, 10% mono-unsaturated, 7% omega-6, 18% omega-3 and 0.4% trans fatty acids. Sperm levels of total trans (r = -0.44), total saturated (r = -0.42) and total mono-unsaturated (r = -0.11) fatty acids were inversely related to sperm concentration whereas sperm levels of total omega-3 (r = 0.75) and total omega-6 (r = 0.45) polyunsaturated fatty acids were positively related to sperm concentration. The median (25th – 75thpercentile) sperm concentration for men in increasing quartiles of sperm trans fatty acid levels were 100.2 (50.4-141.0), 13.5 (3.2-18.0), 12.3 (3.0-49.2) and 2.7 (0.5-50.6) x10 sperm/mL. The corresponding sperm concentrations for men in increasing quartiles of sperm long chain omega-3 fatty acid levels were 0.2 (0.1-5.0), 6.0 (1.1-12.2), 49.2 (17.0-64.5), 89.4 (35.9-101.2).
CONCLUSIONS: Sperm fatty acid composition is related to sperm concentration. The associations of sperm transfatty acid and sperm long chain omega-3 fatty acid levels with sperm concentration suggest a potential role of dietary fatty acid intake on spermatogenesis.
