Drinking Alcohol May Affect Quality of Sperm

New study suggests link between how much alcohol men drink and reproductive hormones

Regularly drinking heavy amounts of alcohol intake can raise the risk for a number of health issues ranging from hangovers to cirrhosis of the liver. New research suggests heavy drinking may also be tied to men's reproductive health.

A recent study found that young men who drank more than five alcoholic beverages a week experienced negative changes to the quality of their sperm. For men interested in reproducing, this may be an issue.

The observational study was conducted by Tina Kold Jensen, MD, of the University of Southern Denmark in Copenhagen, and colleagues.

Men aged 18 to 28 years of age who had a compulsory medical examination to determine their fitness for military service were asked to take part in the study. The researchers found 1,221 men who agreed, filled out questionnaires about their drinking habits and gave blood and semen samples.

The men were asked how much alcohol they had to drink in the week before the questionnaire, and how much they normally drank. They were also asked how often in a month they got drunk and how often they drank more than five units of alcohol in a day, which is considered to be binge drinking.

The men were told that one unit of alcohol was one beer, one glass of wine or 40 milliliters of spirits. A strong beer or cooler, such as hard lemonade, was considered 1.5 units.

Men who said they drank five units in a week had lower quality semen than men who drank less. Semen quality was determined by volume of the semen, sperm concentration, total sperm count and percentage of actively moving sperm.

The quality of semen was markedly reduced among men who had more than 25 units of alcohol in a week.

Men with a usual weekly intake of more than 40 units had a 33 percent reduction in sperm concentration compared to men with an intake of one to five units per week.

Men who drank a lot in the week before their blood was taken had increased free testosterone, a hormone that often binds to a protein known as the sex hormone binding globulin (SHBG). SHBG levels may be used to assess a man's fertility.

Binge drinking did not seem to be associated with changes in sperm or blood levels of reproductive hormones.

Professor Jensen told dailyRx News what she learned from her study. “It surprised me that regular intake of even moderate alcohol had an impact on sperm count. Previously, we have only asked the men about last week’s intake, which was not so strongly associated with sperm count, but habitual alcohol intake seems to be," she said.

The study authors noted that they do not know if sperm quality is restored once some time has passed and the men do not drink more alcohol.

These authors concluded that “young men should be advised that high habitual alcohol intake may affect not only their general but also their reproductive health.”

The study appeared October 2 in BMJ Open.

The study was funded by a number of sources, including he The Danish Council for Strategic Research.

The authors declared no conflicts of interest.