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.

8 responses to “The Splenda Experiment”

  1. Niki says splenda has been linked to cancers too.

  2. Duane Storey says:

    So has pretty much everything, including sugar!

  3. Lynn C says:

    That’s great that you’re seeing positive results already! Can you handle dairy products like yogurt and kefir? (obvious choices for probiotics) If not, maybe a supplement? Apparently probiotic supplements are notoriously unreliable as far as quality/content are concerned but there is a particular brand my cousin (he’s a doctor) recommends. I’ll check it out when I get home if you’re interested.

  4. Duane Storey says:

    Well, I’ve actually taken lots of probiotics, but I never really felt they helped. If my splenda theory turns out being kind right, then perhaps it was countering the probiotics. In addition, the yogurt I used to buy, Yoplait, was actually sweetened with Splenda — ironically enough, I used to think my symptoms got worse when eating it, so I stopped eating it a while ago.

    But pretty much the gold standard in probiotics (at least amongst c. diff sufferers). is called Bio-K. It’s kind of like curdled milk, and it’s pretty gross tasting, but apparently it has the most live cells per serving, and is used in many hospital settings.

  5. Rebecca says:

    I have digestive issues as well (a laundry list!) and have found that eating at least 175g of plain yogurt a day is helping a TON. I put some seeds (ground flax, pumpkin, sunflower) and a bit of fruit, either an apple cut up or blueberries, and its just miles above any yogurt-with-fruit cup concoction. I don’t miss the added sweetener as long as there’s a bit of real fruit involved. I’ve started drinking plain coffee (sometimes with some cream) and don’t miss the sugar/sweetener either. Also – this may sound weird but it does work – try castor oil packs (Google it). Helps a ton with funky digestion.

  6. Bobby says:

    I had stomach problems as well.

    I like to say sucralose, not Splenda, because that is what Splenda is. And it is in a lot of stuff Sadly, the package doesn’t have to say Splenda, or diet, to have sucralose in it. You have to read labels. So, you might still be using it and don’t even know it!

  7. Duane Storey says:

    Yah I’m pretty careful. Plus here in Canada nutrition labels have to be pretty explicit, so you can usually tell easily.

  8. Alan Clark says:

    I started using Splenda in my morning coffee and had a bout of diarrhea every afternoon from day one. I used Splenda for about 10 days until it dawned on me that it might be the cause of my diarrhea. I stopped using Splenda on day 11 and so did the diarrhea. Bye bye Splenda. I’ve read that Sucralose was accidently discovered by some one working in a lab that develops insecticides!!

Leave a Reply

Your email address will not be published. Required fields are marked *