Meat intake and reproductive parameters among young men

Abstract

Background: In the United States, anabolic sex steroids are administered to cattle for growth promotion. There is concern regarding the reproductive consequences of this practice in men who eat beef. We investigated whether meat consumption was associated with semen quality parameters and reproductive hormone levels in young men.

Methods: Semen samples were obtained from 189 men aged 18-22 years. Diet was assessed with a previously validated food frequency questionnaire. We used linear regression to analyze the cross-sectional associations of meat intake with semen quality parameters and reproductive hormones while adjusting for potential confounders.

Results: There was an inverse relation between processed red meat intake and total sperm count. The adjusted relative differences in total sperm counts for men in increasing quartiles of processed meat intake were 0 (ref), -3 (95% confidence interval = -67 to 37), -14 (-82 to 28), and -78 (-202 to -5) million (test for trend, P = 0.01). This association was strongest among men with abstinence time less than 2 days and was driven by a strong inverse relation between processed red meat intake and ejaculate volume (test for trend, P = 0.003).

Conclusions: In our population of young men, processed meat intake was associated with lower total sperm count. We cannot distinguish whether this association is because of residual confounding by abstinence time or represents a true biological effect.

Figure. Processed meat intake quartiles in relation to (A) total sperm count (millions) and (B) total progressive motile count (million motile). Meat intake quartiles: Q1 = 0 - 0.42mL; Q2 = 0.44 – 0.85 mL; Q3 = 0.87 – 1.44mL; Q4 = 1.45 – 5.25mL

Models are adjusted for age, abstinence time, race, smoking status, BMI, recruitment period, moderate-to-intense exercise, TV-watching, dietary patterns, and total calorie intake. Tests for trend were conducted across quartiles using a variable with the median processed meat intake in each quartile as a continuous variable in the linear regression models. for total sperm count, P =0.01; for total progressive motile count, P = 0.02.