High Cola Intake Linked to Low Sperm Counts

COPENHAGENMen who consume more than a quart of cola daily have nearly 30-percent lower semen counts than men who consume significantly less, according to a new Danish study published in the American Journal of Epidemiology.

Researchers examined the association between semen quality and caffeine intake among 2,554 young Danish men recruited when they were examined to determine their fitness for military service in 20012005. The men delivered a semen sample and answered a questionnaire including information about caffeine intake from various sources, from which total caffeine intake was calculated.

Moderate caffeine and cola intakes (101800 mg/day and 14 0.5-L bottles of cola/week) compared with low intake (100 mg/day, no cola intake) were not associated with semen quality. High cola (>14 0.5-L bottles/week) and/or caffeine (>800 mg/day) intake was associated with reduced sperm concentration and total sperm count, although only significant for cola.

High-intake cola drinkers had an adjusted sperm concentration and total sperm count of 40 mill/mL (95 percent confidence interval (CI): 32, 51) and 121 mill (95 percent CI: 92, 160), respectively, compared with 56 mill/mL (95 percent CI: 50, 64) and 181 mill (95 percent CI: 156, 210) in non-cola-drinkers, which could not be attributed to the caffeine they consumed because it was <140 mg/day.