Drinking more than two pints a week could have negative effects on men's semen quality, a study has found.
The higher the alcohol consumption that was reported by young Danish men, the lower the quality of their semen, reported the study authors, who recommend that young men avoid habitual drinking.
'This is, to our knowledge, the first study among healthy young men with detailed information on alcohol intake, and given the fact that young men in the western world drink a lot, this is of public health concern, and could be a contributing factor to the low sperm count reported among them', the study authors said.
The study looked at 1,221 men aged 18 to 28 years who underwent a medical examination to assess their fitness for military service, which is compulsory for men in Denmark. The research team also invited the men to provide a semen sample to check their sperm quality, as well as a blood sample to check reproductive hormones. Around 30 percent of men who were invited participated in the study.
Compared to men who reported drinking one to five units of alcohol a week, men who reported drinking more than 40 units of alcohol in a typical week (13 to 20 pints of beer) had a 33 percent reduction in sperm concentration.
However, the team also found negative effects on semen quality in men drinking more than five units a week, with less sperm being produced, and more sperm of abnormal size and shape. 'The effect was there, albeit smaller, with just five units a week, so it's troubling', Professor Tina Kold Jensen, lead author of the study, told the Washington Post.
The team cannot rule out that the associations they found in this cross-sectional study are in fact due to other lifestyle factors, such as poor diet or smoking, that might accompany alcohol consumption.
Professor Jensen is not sure whether the presumed effect of alcohol on sperm quality is permanent. 'Hopefully it would reverse within three months, because that's how long it takes new sperm to mature', she said. 'But having said that, it's easy to recommend that young men drink less. We know it's healthier for your liver, and most other things'.