A friend sent me a text message asking a very strange question:

“Can cola kill pathogens after swimming?”

It seemed like an easy answer:

Swimmer’s stomach is a rather annoying condition whereby bacteria swallowed from natural waters end up giving people GI distress usually leading to diarrhea and sometimes vomiting. It’s not fun and any means to prevent the symptoms is welcome news.

But drinking cola? For me it seemed highly unlikely.

Yet the swimmer who swears by it also happens to be an Olympian and one of Canada’s better hopes for a medal.

Richard Weinberger, the 2012 bronze medalist in the Olympic 10K

You can read more about Richard and his quest – as well as his belief in cola – here:
Weinberger Predicting An “Epic” Olympic 10K Race In Rio de Janeiro

So, giving the swimmer the benefit of the doubt, I went in search of a possible mechanism behind his assertion. There were no clinical trials so any evidence he gave was purely personal and word of mouth. But that wasn’t a good enough reason to call it bunk. I wanted a mechanism to provide an explanation as to why it didn’t work – and also why people thought it might.

Then something strange happened. I came across an article from over 15 years ago. It was a rather obscure paper about killing E. coli on animal hides. You can see the abstract here: http://www.ingentaconnect.com/content/iafp/jfp/1999/00000062/00000006/art00003
The mechanism involved using phosphoric acid – just like the stuff found in cola – and mixing it with acidified salt water.

For me, this was an instant:

OSLO 20090612: A-ha med f.v. Paul Waaktaar-Savoy, Morten Harket og Magne Furuholmen inntok fredag Oslo for å markedsføre sitt nye album 'Foot of the mountain» som kommer i salg 15. juni. Foto: Berit Roald / SCANPIXA-HA! (if you don’t get this, ask your parents)

Reading the paper allowed me to see what could be happening in the gastrointestinal tract and why this cola trick might work. If you’re wondering, it goes something like this:

  1. Drink seawater – this is the only reason it works…freshwater won’t have any effect;
  2. Let it get acidified in the stomach – should be at least a few minutes if not more;
  3. Add phosphoric acid – drink the cola;
  4. Bow head for the gold medal – okay, this only applies to Weinberger.

I’m not saying this mechanism is actually occurring or that the technique works in the body. For that to happen, there would have to be clinical trials. Yet, as with many traditional remedies, this medical benchmark may never be reached.

For people like Weinberger and others, the answer comes down to whether they believe the mechanism. He does and if he stays safe, I’m happy for him. I admit I am skeptical. Yet, if I had known this idea when I was in Rio last year (and swallowed all that seawater) I might have given it a try.

As for my friend’s text message asking about cola and swimming, I know the people asking swim in the pool, not in the ocean. So in this case, the only answer is a very simple and emphatic: