A good old urban legend that I still remember to this day is that the soft drink Mountain Dew kills sperm and reduces their overall sperm count. This has been, at least for me, something I’ve heard since the playground days during grade school. And at the time it made sense, its the only green soft drink and its very acidic and sweet. It fit the profile and at 13 or so years old I wasn’t gonna question it. But now that I have explored science through this class it’s time for me to actually find the answer.

We first need to start out with how did this myth start or more or less what about mountain dew created this bizarre accusation but left Sprite, Pepsi, and Coke aside from this. Mountain dew has a great amount of ingredients but the two that stick out the most in this myth are caffeine and Yellow dye #5, also known as Tartrazine. If you break down this two ingredients we can see that something isn’t adding up. Mountain dew contains 54mg of caffeine in a 12 oz can.  That might seem like a lot since coke has 34mg per 12 ounces, Dr. Pepper has 41, and Pepsi has 38. If we had to count on caffeine to be the reason for the reduction of sperm then we need to look at other high caffeine drinks and see how they compare. The average cup of coffee has 217mg per 12 ounces, about 4 times more than the Mountain Dew! So for comparison’s sake, Mountain Dew doesn’t contain very much caffeine, compared to other things many commonly drink. With even more proof “The Chemical Health Hazard Assessment Division of the Canadian Bureau of Chemical Safety reviewed all the current studies on the subject and found that they showed that if a man drank one or two
cups of coffee per day, he would have an increase in his sperms motility and density.” So at this point caffeine if anything is doing the exact opposite and actually increase the quality of sperm.

But we aren’t done yet. We still have yellow dye #5 or Tartrazine. Tartrazine can be found in anything and everything ranging from ice cream to your favorite bag of chips to chewing gum. Tartrazine is very water soluble so most of Tartrazine you put in your body will run right through kidney and come out in your urine. Very little is actually metabolized by our bodies. The European Food Safety Authority re-evaluated the effects of Tartrazine in 2009.  “There ar
e no adverse effects on reproduction or development from consuming Tartazine.” They even tested people at a rate of 1225 mg/kg and still found no adverse effects. Sperm affects aside, the FDA does recommend that we should only ingest 5 milligrams per kilogram per day of Yellow dye #5. But all of this has to do strictly for allergenic reasons not reproductive reasons. But this is only due to the fact that there are only a very small percentage of people who are allergic to it. (1/1000) 

So there you have it. Myth busted! Mountain Dew’s long lasting accusation of reducing sperm count has been proved wrong. Caffeine and yellow dye #5 the main ingredients that fueled the myth actually have zero effect on reproduction of sperm and at the end of the day all men can rest easy now and sit back and enjoy Mountain Dew.