Is Caffeine Linked to Male Infertility?
Caffeine is the most widely consumed psychoactive drug in the world. Hundreds of millions of people are technically junkies, imbibing that morning brew simply to stave off the fatiguing effects of caffeine withdrawal.
As caffeine is so widely consumed, scientists regularly study the stimulant. (After all, many of them are self-professed junkies, as well, and so nurture a personal interest.) Caffeine boosts athletic performance. Caffeine attenuates symptoms of depression. Caffeine raises blood pressure. The effects are endless.
Yet, an arena that has surprisingly escaped noticeable study is caffeine's link to male infertility. A group of Italian researchers recently filled the information gap with a systematic review published to the Nutrition Journal.
After pouring through the published research, the reviewers turned up 28 relevant studies featuring nearly 20,000 subjects. They then scrutinized each study to uncover caffeine's effects on semen quality, sperm DNA, and the time required to conceive.
Overall, daily drinkers of caffeine should be happy with the results.
The reviewers didn't find any adverse effects of caffeine intake on semen volume, sperm count, sperm concentration, or sperm motility. However, one study did find that men drinking more than four cups of coffee per day had a slightly higher proportion of abnormally shaped sperm.
As for caffeine's effect on the time needed to conceive a child, studies generally found no effect of moderate consumption. Men drinking fewer than three caffeine beverages per day shouldn't be concerned that their caffeine habit will interfere with getting a partner pregnant.
The reviewers did return one disconcerting finding. A number of studies found that daily caffeine intake is associated with increased sperm DNA damage in the form of double-strand DNA breaks and aneuploidy, the presence of an abnormal number of chromosomes. Conceivably, such damage could lead to difficulty conceiving or a higher rate of genetic aberrations in children. This potential link is tenuous, however, and requires further study.
It should be noted that not all caffeine drinks are created equal. The reviewed studies consistently showed that daily consumption of caffeinated soft drinks was highly associated with male infertility, likely due to the sugar content. Low-calorie tea and coffee were generally not detrimental.
According to current scientific evidence, men consuming caffeine in moderation shouldn't be too concerned that their habit will hinder their fertility.
Source: Elena Ricci et al. "Coffee and caffeine intake and male infertility: a systematic review." Nutrition Journal 2017 16:37 DOI: 10.1186/s12937-017-0257-2