"Internet search engines are the epitome of confirmation bias"
- Neil deGrasse Tyson
I was working nightshift recently and I noticed that after I’d eaten some yogurt sweetened with stevia, I was frequently waking up to pee while trying to sleep during the day.
Anyone who works nights knows how big of a deal it is to wake up to pee when it’s light outside. It is pretty much THE SLEEP DEATH SENTENCE.
I started looking into stevia's effect as a diuretic since nothing else had changed as far as I could tell, so the first thing I did was Google "Is stevia a diuretic?"
Low and behold - pages and pages of both fitness and health sites claiming that yes, in fact, stevia is a diuretic and worse yet: It'll kill ya’.
Pretty harsh, right? All this "data" claiming all these bad things and all these websites confirming it. It must be true, right?
Once you start looking at the research papers behind these claims, they fall apart quickly.
Most often these studies (and in fact most nutritional studies) are performed on rats. There are a lot of reasons for this, and it’s a perfectly acceptable way to gather data and make educated claims.
Creating nutritional studies is difficult to do in humans, and rats allow for a more controlled, larger, and longer-term study.
Not everything translates perfectly into humans however, but that’s okay. We still get a good picture of what’s happening.
The two studies (that's right, only two) that found a diuretic effect from stevia required [1] a much higher dosage than is used for any sweetening purpose, or [2] an IV dosage in amounts greater than used for sweetening purposes.
When given a lower dose of 0.5mg/kg/h no diuretic effect was found whatsoever.
For reference, the ADI (adequate daily intake) of stevia is 25mg/kg, which is more than you would use to sweeten a drink like tea and much more than is seen in the yogurt I was eating.
This is an example of the rampant confirmation bias that plagues our society today and is all the more reason to be diligent and skeptical of the information we digest.
All too often I see popular and influential people talking about a subject, and people just taking their opinions as facts regardless of their context or true authority on the subject.
It’s catchy and popular to make claims like this. Just look around you and you will find thousands of strong opinions on all things diet and nutrition-related, and much of it contradictory. Unfortunately, it sells and will continue to be prevalent.
[1] Melis MS, Rocha ST, Augusto A. Steviol effect, a glycoside of Stevia rebaudiana, on glucose clearances in rats. Braz J Biol. 2009 May;69(2):371-4. doi: 10.1590/s1519-69842009000200019. PMID: 19675940.9 [2] Melis MS. A crude extract of Stevia rebaudiana increases the renal plasma flow of normal and hypertensive rats. Braz J Med Biol Res. 1996 May;29(5):669-75. PMID: 9033821.