The Splenda Experiment

Last modified on August 3rd, 2009

As I mentioned a few days ago, I decided to try giving up Splenda to see if that helps my stomach out at all. Splenda is a sugar substitute (technically called Sucralose), and it’s chemically similar to sugar, although it has a few chlorine atoms added on which makes it mostly indigestible.

Unfortunately, since most sugar substitutes essentially can’t be processed by the body, they can sometimes cause some distress as they pass through. At the top of that list are certain sugar alcohols (which are used in gum and lots of chocolates), which sometimes have a strong laxative affect.

I came up with two working theories to my own stomach problems — one was that they may be caused by carbonated beverages (such as diet pepsi), and the other involves Splenda. My main reasoning was that in periods of time where both of those were reduced (such as when I was in the Caribbean a few months ago), I ended up feeling quite a bit better.

Given how I usually read new medical research every Sunday night, I did a quick scan for Splenda to see if I could find anything. What came up was a recent study from Duke university involving Splenda fed to rats (which typically respond to a lot of foods the same way humans do):

Splenda is comprised of the high-potency artificial sweetener sucralose (1.1%) and the fillers maltodextrin and glucose. Splenda was administered by oral gavage at 100, 300, 500, or 1000 mg/kg to male Sprague-Dawley rats for 12-wk, during which fecal samples were collected weekly for bacterial analysis and measurement of fecal pH. After 12-wk, half of the animals from each treatment group were sacrificed to determine the intestinal expression of the membrane efflux transporter P-glycoprotein (P-gp) and the cytochrome P-450 (CYP) metabolism system by Western blot. The remaining animals were allowed to recover for an additional 12-wk, and further assessments of fecal microflora, fecal pH, and expression of P-gp and CYP were determined. At the end of the 12-wk treatment period, the numbers of total anaerobes, bifidobacteria, lactobacilli, Bacteroides, clostridia, and total aerobic bacteria were significantly decreased; however, there was no significant treatment effect on enterobacteria. Splenda also increased fecal pH and enhanced the expression of P-gp by 2.43-fold, CYP3A4 by 2.51-fold, and CYP2D1 by 3.49-fold. Following the 12-wk recovery period, only the total anaerobes and bifidobacteria remained significantly depressed, whereas pH values, P-gp, and CYP3A4 and CYP2D1 remained elevated.

The report concludes with a summary indicating how the rats responded to typical dosages of Splenda:

These changes occurred at Splenda dosages that contained sucralose at 1.1-11 mg/kg (the US FDA Acceptable Daily Intake for sucralose is 5 mg/kg). Evidence indicates that a 12-wk administration of Splenda exerted numerous adverse effects, including (1) reduction in beneficial fecal microflora, (2) increased fecal pH, and (3) enhanced expression levels of P-gp, CYP3A4, and CYP2D1, which are known to limit the bioavailability of orally administered drugs.

Given that IBS is theorized to be caused by a disruption in the intestinal flora, and the disruption of flora is often the precursor to c. diff. (which I had), point number 1 isn’t really a good sign.

I’ve been Splenda free for about four days day, and so far I think I feel better, as evidenced by the lack of a rumbling stomach. So I’ll keep at it for a while and see how things shape up. But so far so good.