The more alcohol men drink, the lower the quality and concentration of their sperm, according to new research published in the journal BMJ Open last week.
Being intoxicated can lead to changes in hormones and other chemicals in the body, including cortisol, glucose, and insulin, all of which can affect sperm quality, according to Dr. Michael Heard, an obstetrician, gynecologist, and reproductive endocrinologist at The Heard Clinic and Houston Methodist Hospital in Texas.
The research found a negative association between sperm concentration (i.e. sperm count and quality) with increasing habitual alcohol consumption. Sperm concentration was poorer among men having at least five drinks a week compared to those having just one drink weekly. The drop in sperm concentration was the most pronounced in men who consumed at least 25 drinks weekly.
The cross-sectional study observed 1,221 Danish men between the ages of 18 to 28, who were examined to determine whether they were fit for military service between 2008 and 2012. The men were asked about their drinking habits, and provided semen and blood samples.
It’s important to note that the study was not able to show that alcohol had a direct effect on sperm concentration, only that increased alcohol consumption was associated with fewer and less quality sperm.
“We tried to adjust for other possible factors like diet, smoking, weight, etc., which did not explain the association,” said Dr. Tina Kold Jensen, a professor of environmental medicine at the University of Southern Denmark. “But we cannot rule out whether this effect may be due to other factors [not measured] associated with alcohol intake.”