Caffeine and Dehydration

[Jason Silvernail]

Hello everyone.
I've attached the most recent "ACSM Fit Society Page", where ostensibly good information for consumers about health and fitness can be found.

I got an email link to it since I'm an ACSM (https://www.acsm.org/AM/Template.cfm?Section=Home) member.
I found the article on diet soda particularly disappointing and I wrote a letter to the editor about it. I'll post that next, along with some research on caffeine and dehydration.

[Jason Silvernail]

Here is my letter to the editor regarding the diet soda article. I've attached the latest review showing regarding moderate caffeine consumption and dehydration as well.

"I am an ACSM member and I'm writing about the ACSM Fit Society Page. As a new member, this was the first time I had read it. I was very disappointed with the article on diet soda by Haley Kirby LAT.

This article appeared to misinterpret a great deal of research and appeared to present diet soda as a health risk. Now, I don't believe diet soda is an appropriate sports drink (nor do I work for a manufacturer), but I would expect ACSM to present in one of it's publications a more even-handed treatment of any given subject. For example, I was pleased to see in the Q&A column Dr Luke's summary of the research for and against glucosamine and chondroitin for arthritis pain. This is the sort of balanced commentary based on published research that I would expect from ACSM.

Unfortunately, Haley Kirby's treatment of diet soda read like a column in a popular fitness magazine designed to scare people with eye-catching headlines.
The summary of the research related to diet soda is of particular concern. Specifically, the author makes the classic "correlation-causation" error several times, leading to what are essentially outrageous statements about the health effects of consuming diet sodas.
For example, he or she wrote, "In fact, some sources claim that there is a more than 40 percent increase in the risk of obesity with each can or bottle of diet soda a person drinks each day." The obvious conclusion here is that if I were to drink three cans of diet soda per day, I would have increased my risk of obesity by 120%. Of course, drinking 2 1/2 cans of diet soda per day does not create a 100% risk of obesity in an an otherwise healthy person - but that certainly is the impression left by the author.
Also mentioned is the effect of caffeine and dehydration as the "most important side effect of diet soda". The author's discussion of dehydration is nice, but it contradicts the latest research on caffeinated drinks and dehydration by Armstrong et al. in ACSM's own Exercise and Sport Science Reviews in July of 2007!
After this, the author falls into the correlation-causation trap again and misinterprets research showing a certain percent reduction in the risk of cancer by drinking 5 glasses of water per day. Much like the example above for obesity risk, a read of the article suggests that a woman could reduce her risk of breast cancer by 79 percent simply by drinking five glasses of water per day! I think this is the sort of misinformation found in the popular media that makes the job of healthcare providers harder - in addition to providing accurate information about disease risk and lifestyle changes to our patients, we now have to spend a portion of an already-shortened visit by "debunking" this sort of sloppy journalism and misinformation.

I enjoy being an ACSM member and I want only the best and most accurate information presented to consumers, especially if it has the ACSM's name on it. I hope in the future such mistakes and misrepresentations can be avoided with more rigorous author selection and editorial oversight.

Thank you for your time.

Jason Silvernail DPT,CSCS
ACSM Professional Member"

Further discussion encouraged...

[nari]

Good on you, Jason. Misinformation about what we should or should not consume is rampant.

My question: What is Diet Soda? Carbonated water with saccharine??

Nari

[Jason Silvernail]

Nari-
Essentially you're correct on what diet soda consists of. Don't forget the caramel color!
:)

[Jon Newman]

Don't forget "natural flavors"

Mmmmm, flavors.

[Diane]

Usually caffeine is added too, right?

[Randy Dixon]

I can't tell you how many times I have heard people say that drinking a caffeinated soda is actually "dehydrating". I also here the same about beer, something that is about as true:
http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=491236&in_page_id=1770

The new thing we are hearing about of course his hyponatremia, a real risk, which will no doubt become a fad thing with new swings in advice to combat it.

[nari]

I also read in our newspaper some years ago that coffee and alcohol were not dehydrating - the crucial aspect is to maintain fluid levels during the day whether exercising or not, regardless of what the fluid contains. (Unless it's salt water).
At the same time, the writer (a sports doc, from memory) advocated that colourless urine is not a good sign, ever, and may indicate hyperhydration which can be lethal. He made a dig at those who suck "mineral" water bottles endlessly when not active.

Nari