A new study is showing that excessive caffeine intake may affect male fertility. The study by Italian researchers, published in Nutrition Journal, showed that increased caffeine intake may affect male reproductive function, possibly through sperm DNA damage.
The study compiled data from approximately 20,000 males involved in 28 previous research studies that looked at the relationship between male coffee/caffeine intake and reproductive outcomes. It looked at semen parameters, sperm DNA characteristics, and ability to conceive.
In most of the included studies, semen parameters (sperm count and motility) did not seem to be affected by caffeine intake. Some studies did show, however, that increased caffeine intake was associated with a prolonged time to pregnancy. Some studies also showed that excessive caffeine intake was associated sperm DNA defects, such as breaks in the DNA strands. This suggests that excessive caffeine intake may cause some damage to the sperm and thereby negatively impact male reproductive function.
Overall, it’s hard to draw any significant conclusions from this compilation of data. The studies included in this review were all so different that it’s like comparing apples to oranges. Like most things, I would say that caffeine in moderation is still fine. Until we see some better studies come out, 1-2 cups of caffeine intake per day doesn’t seem to be harmful to male fertility.