Drink Pepsi. Lose Sperm.

I don’t know about you, but my phone has a Starbucks/Coffee Bean locator that I use at least a dozen times more often than my phone itself and in our increasingly sleepless and workaholic society I suspect most of you are right there with me.  Caffeine can easily be considered our most common go-to drug of choice and for those of us who don’t go overboard it has been shown to have a number of positive physical and mental effects.  However, most of us don’t think about caffeine in terms of our sexual health. Yet it appears that while it might be great for that little mental boost, in high quantities it may not be exactly a pick-me-up for other equally important areas.

A recent Danish study, published in the American Journal of Epidemiology, has shown that there seems to be a correlation between high caffeine intake and reduced sperm concentration and overall count.  However, devoted coffee drinkers rejoice!  It appears that your source of caffeine may be the more important consideration, as the biggest culprit is our other ubiquitous supply of caffeine: soda.  While the Danish study did observe the negative effect on sperm with high levels of caffeine in general, the results were only statistically significant in men reporting excessive levels of soda intake.  Unfortunately, with nearly 20% of adult men in the U.S. reportedly consuming soda more than 3 times weekly, many could easily be reaching that level.  The actual numbers (sperm/milliliter semen) may be somewhat meaningless, but using my significant biostatistical prowess with simple division, the change amounts to a 30% reduction in total sperm for men who drank more than 34 ounces of soda per day or 14 bottles per week.  Additionally, soda consumption was shown to cause this decrease in semen volume, sperm concentration, and sperm with normal appearance.

Perhaps unsurprisingly, and certainly relevant, there was also a correlation between those men reporting excessively high levels of soda consumption and additional unhealthy lifestyle behaviors.  These men also tended to eat foods high in saturated fats and have less healthy diets overall, and they drank and smoked more.  This of course brings us to the larger issue and one in which I am particularly passionate.  While the authors did their best to control for such possible confounders, their study is more important as a comment on lifestyle.  It is safe to assume that the blame for inadequate sperm cannot be solely placed on soda.  Similarly, your low-performing swimmers cannot be blamed on burgers, or beer, or even cigarettes.  In the end it is the accumulation of our overall personal lifestyle choices that is the culprit.  I’ve always felt that one of the hallmarks of a real man is taking responsibility for your actions.  So in this age of fierce partisan rhetoric and regardless of your beliefs on government being involved in your health care, personal responsibility is something around which we should all be able to rally.  Oh, and for goodness sakes stop drinking soda.

“Personal responsibility extends to lifestyle; that in order to have a healthier America, a more productive America, we need to make some basic changes in what we eat, how much we exercise…”

– Democrat & HHS Secretary Kathleen Sebelius

“Placing responsibility squarely where it belongs, on the shoulders of the patient, will encourage individuals to make healthy lifestyle choices…”

– Conservatives for Patients’ Rights TV ad


Jensen TK, et al. Caffeine intake and semen quality in a population of 2,554 young Danish men. Am J Epidemiol. 2010 Apr 15;171(8):883-91.

Joelving, F. Is cola bad for sperm? Reuters Health. March 29, 2010. https://www.nlm.nih.gov/medlineplus/news/fullstory_96992.html

Luke Manley, MPH

View posts by Luke Manley, MPH
Luke grew up in and around Boston, Massachusetts before moving north to attend the University of Maine at Orono for his undergraduate degree. After living briefly in Portland, Oregon he is now working as a Research Phlebotomist and Grants Manager for the Psychiatry Department at the University of Southern California. His passion lies in travel and working internationally, especially in the Middle-East. He has spent time in Turkey, researching the Turkish Healthcare system and recently returned from Syria, Palestine, and Tunisia, assisting with the MedCHAMPS project, which is studying cardiovascular morbidity and mortality. In the Fall he will be moving to Washington, D.C. to pursue a PhD and begin his career in International Relations.


  1. DebbieMay 12, 2010

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  2. Natalie PortMay 12, 2010

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  3. Ahsan SayedJuly 14, 2010

    Great peice!

  4. Melatonin Supplement October 19, 2010

    my healthy diet routine include lots of dietary fibers, vegetables and fruits, i always cut down on beef and pork`-`

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