Why does 60% of the world’s population over 15 years old drink alcohol? Some imbibe for social reasons, to enhance sociability and enjoyment, and others bend an elbow to help cope with problems or stress. Regardless of motive, excessively hitting the sauce, which has been reported in 25% of U.S. adults, can have serious social and health implications. Witness the fact that alcohol, not opiates, is the leading drug-related killer in America. The question today is: does alcohol also impair fertility?
Hard Effects of Alcohol
Before I address fertility, I would be utterly remiss if I didn’t mention how powerfully alcohol is known to affect pregnant women: Fetal Alcohol Spectrum Disorders. Alcohol easily crosses the placenta and accumulates in amniotic fluid, in turn exposing the fetus to alcohol. With fetal cognitive and birth defects attributed to alcohol in 2-5% of U.S. births, this is a problem of epidemic size by any measure. And, since no “safe” dose of booze has been defined, the uniform recommendation is that pregnant women completely avoid it.
Firewater & Male Fertility
But what’s known about male fertility and booze? It’s clear that even a single night of getting sauced can acutely impair erections and ejaculation due to alcohol’s anesthetic action. Not a great thing for either date night or baby making. More importantly, too much joy juice can also affect testosterone balance, sperm production and sperm function. Male hormone production by the testes is lowered by alcohol-induced changes in brain signaling. In addition, alcohol revs up liver enzymes that convert testosterone to female hormones, and these jacked-up estrogens further suppress brain signals to make testosterone. All in, less testosterone means fewer sperm, lower sperm counts, and testis shrinkage. Not a pretty sight.
But there’s more. Booze creates an oxidative or “inflammatory” environment around and within cells. And oxidative stress affects the sperm DNA payload by altering sperm shape or morphology and increasing DNA fragmentation, mutations and epigenetic changes that are entirely unwelcome and known to impair male fertility. No doubt about it, alcohol is a sneaky little water-soluble molecule that gets into every body organ and crevice and wreaks all kinds of biological havoc.
Less is More
Now that we’ve seen how suds and firewater can beat a testicle down, I need to qualify things a bit. These awful consequences of alcohol on male fertility have really only been found with excessive alcohol use (>5 drinks in 2 hours). They have not been reliably demonstrated with mild to moderate alcohol intake (2 drinks or fewer daily). Some studies have shown only impairments to sperm shape or morphology in men who regularly drink some alcohol, without other notable changes to sperm. Based on this body of evidence, the current recommendation is for men who drink heavily to decrease their alcohol intake for optimal fertility. And for light booze users, modify consumption based on overall health status to stay reproductively fit.
So, when you next sip that slow gin fizz and ponder fatherhood, remember the words of humorist Finley Peter Dunne: “Drink never made a man better, but it made many a man think he was better.”