Drinking can harm sperm
Just five alcoholic beverages a week can make a difference
It goes without saying that drinking in excess is bad for your health, but it might also hurt your chances of reproducing.
In a survey of men between ages 18 and 28 in the journal BMJ, researchers reported that as few as five drinks a week affected sperm quality.
In the study, men who drank an average of five to 10 units (one beer, a glass of wine or 40 millilitres of liquor is considered a unit) of alcohol a week had a slight decrease in sperm concentration, total sperm count and percentage of healthy and normal sperm.
The effect became much more pronounced at 25 units a week (3.5 drinks a day), and men who averaged 40 units a week had a 33-percent reduction in sperm concentration compared with the lightest drinkers. The study is just a preliminary one — surveying 1,221 Danish men during medical exams required before their compulsory military service — but lead author Tina Kold Jensen says that it may paint a more accurate picture of male drinking and its effects than previous studies.
Jensen and her colleagues started by asking the men to give a detailed account, unit by unit, of what they’d had to drink the week before.
Then the researchers asked the men to decide whether that week had been typical.
It was easier for the men to remember the specifics of the previous week’s consumption than it would have been to estimate their overall averages — a prompt that usually leads to people underestimating how much they drink. But it also weeded out those who had happened to binge-drink the week before.
Sure enough, heavy drinking affected sperm quality only in the men who reported that it was just their normal routine.