Alcohol use in men has been shown to have possible negative effects on sperm (decreased semen volume, movement, shape, and count), with inflammation and increased white blood cells in the semen. Alcohol intake is associated with lower levels of fuel (gonadotropins) from the brain and direct effects on the testes leading to lower testosterone. Increased B-endorphin, a naturally occurring chemical (neurotransmitter) of the body, which occurs with chronic alcohol use has been implicated as a possible culprit. Semen changes do not appear to correspond to alcohol quantity (heavy alcohol use defined as more than 3 ounces per day) or duration. Changes may be reversible following discontinuation of alcohol (after approximately 3 months of stopping in mouse and human studies). In mice, sperm precursor cells undergo cell death when treated with alcohol, but the reasons for this are not clear. Genetics may play a role in some individuals having greater susceptibility to alcohol caused sperm disorders (for example GST M1 gene).
Despite possible semen changes, overall fertility of the couple has been shown in some studies not to be affected by alcohol, while other studies show that the risk of not achieving successful birth of a child following assisted reproductive technology (in vitro fertilization, IVF) was increased according to each additional drink (including beer) of the male partner during IVF. Interestingly, a specific component of red wine, myricetin has been recently shown to affect sperm motility and survival and might interfere with sperm fertilization of egg in the female reproductive tract.
You might wonder: “How does a mother’s alcohol intake during pregnancy affect her male children?” A study from Denmark evaluated the effects of a mother’s alcohol intake on semen quality of sons. The sons of mothers exposed to more than 4.5 drinks per week during pregnancy had mean sperm concentration 32% lower than the concentration of sons exposed to <1 drink per week (59 million/ml). Semen volume was also lower in the higher prenatal alcohol exposure group.
Bottom line: Overall, alcohol consumption in men trying to father a child can cause sperm abnormalties and decreased testicular function. An absolute cutoff level for a safe amount of alcohol is unknown. More work regarding genetics to determine which men are at highest risk is required. For now, until additional studies are completed, the best bet for men would be to consume alcohol in moderation when attempting to father a child either naturally or with assisted reproductive technology (IVF) so that your sperm can be all that they can be!
For more information about factors affecting male fertility and options for management, please visit the Center for Male Health and Reproduction site. You may also contact us with any additional questions and our physician team will respond.
–Matthew Wosnitzer, M.D.
February 1, 2014