The Slow Death of Artificial Sweeteners?

Filed under: General Health, Nutrition

Recently on the Precision Nutrition blog there was a review of some research on the potentially adverse health effects of consuming artificial sweeteners like Splenda. I am going to give an overview of the study and discussion and give my take, but if you would like a more in depth look strictly at the research, check it out here. I also recently blogged about antibiotics and their effects on intestinal flora, right here.

This research focused on the administration of Splenda to rats to see the effect on their intestinal flora. Though not identical, the human digestive system is not all that dissimilar from rats, so results from this type of work usually translate quite well.

There were several different dosages given along with a control group not receiving any Splenda. The lowest treatment group had an intake below the expected daily intake of a human, based on the rats bodyweight so the percentage of sucralose to bodyweight would be the same. The next lowest group was above expected intake, but still well below acceptable levels for health concerns. The last two treatment groups were above the acceptable intake.

The study lasted 12 weeks and had some scary results. In the lowest treatment group, well below even the expected daily intake let alone levels considered to be the anywhere near the upper limit of safe, the amount of good bacteria in the gastrointestinal tracts had decreased by nearly 50%! Even after a 12 week washout period where no Splenda was consume, that lowest level intake group still had nearly 54% less good bacteria than before they began Splenda consumption. This effect was seen at all dosages and only got worse as the treatment does went up. That is some scary stuff right there, doesn’t make those artificially sweetened yogurts sound so appealing now does it? Talk about self-defeating!

This destruction of intestinal flora can weaken your immune system and cause plenty of digestion issues. There was some other interesting points in the article about weight gain. The lowest treatment group actualy gained weight from the Splenda, as did the third treatment group. The second and highest did not. Odd, but one possible explanation is that the body has what Helen Kollias called “threshold levels of compensation to sucraslose” (the artificially sweet part of Splenda). That is why there was weight gain in the lowest group, but not the next as the higher intake caused a compensation of specific proteins to remove it, the next highest dose didn’t trigger a higher compensation so there was some weight gain seen there, and the highest dose reached a new threshold where the removal proteins were upregulated yet again. This is a double edged sword that Helen goes into more detail about, some interesting stuff.

In conclusion, we need more research, preferably on human subjects, but still I suggest resorting to consuming as little Splenda, or any artificial sweetener at that, as possible. Focus on real whole food, preferably local, seasonal and usually organic. I understand it’s not easy, but your GI tract and your immune system will thank you.

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Posted on March 25th, 2009 by Brian St. Pierre


  1. schnupi Says:

    Interesting.. but how about xylitol?

    I mean it is a sweetener, but judging from the few readings I did about it, it’s a natural sweetener not artifical.

    I am asking because I currently live in China and basically all yoghurts here have some sort of sugar in there(seems like Chinese can’t eat much natural foods). The xylitol ones have the best nutrional value so I usually go for them.

    Should I avoid them afterall?

  2. Brian St. Pierre Says:


    There are certainly exceptions. Xylitol being one of them. There is no known toxicity of xylitol, like other sugar alcohols it is a mild laxative, though it appears to have a weaker effect. It is slightly lower in calories than regular sugar and has shown to have actual health benefits such as: prevention of dental caries, and the prevention of bacterial and yeast growth. I think some xylitol is ok, though again I would not go out of your way to consume it.

  3. schnupi Says:

    Thanks Brian,

    I usually avoid all sorts of sweeteners, but in my situation it’s the best I can do..Its virtually impossible to find non-sweetend yoghurt in Shanghai.

    Will have to wait until I am back home for some normal food I guess :P

  4. Tues WOD - Back Squats | Says:

    [...] Study of Splenda Recently on the Precision Nutrition blog there was a review of some research on the potentially adverse health effects of consuming artificial sweeteners like Splenda. I am going to give an overview of the study More>> [...]

  5. JMJ Says:

    I saw the post over on PN recently. Thanks for putting your spin on it as well, BSP. I used to add 1 splenda to my green tea (2 cups a day), but not any more. I need my healthy bacteria !

  6. Bob Parr Says:

    Hi Brian,

    Avoiding artificial sweeteners isn’t too hard for me because I don’t have much of a sweet tooth anyway, but what about protein shakes?

    It seems most brands of whey protein are sweetened with sucralose: even premium brands like Biotest.

  7. Brian St. Pierre Says:


    That is a concern of mine as well, and I am not yet sure what direction I want to go with it. For now I am finishing up my metabolic drive and ultra peptide, then we will see. I am looking into some alternatives such as Sun Warrior rice protein, and Paleomeal whey, though neither is cheap, I will blog about that when the time comes.

  8. Jeff Says:

    Im using xylitol for dental health..some people claim that using xylitol and a strict dental regimen you can eliminate the cavity-causing bacteria strain from your mouth in about 6 months- just for kicks im going to try..

  9. Gut Health - More Important than Ever : The Home of Brian St. Pierre Training Says:

    [...] is pretty intense. Just more evidence to show why eating stuff like sucralose, which could potentially destroy half the bacteria in your gut or more may not be a good idea. Why [...]

  10. Nance Says:

    Hey Brian,
    What about Stevia?

    Thanks – Nance

  11. You Asked, I Answered : The Home of BSP Training & Nutrition Says:

    [...] First off, thank you for the kind words, much appreciated. Like with most nutrition questions, the answer is context dependent. Are you cutting years off your life by consuming Splenda once in a while? No, probably not. If you consume a significant amount on a daily basis, this could pose problems. I wrote an entire blog about why I don’t like Splenda. [...]

  12. Friday’s Random Thoughts : The Home of BSP Training & Nutrition Says:

    [...] And that is just for aspartame. There is also research on the negative health effects of Splenda, which I have blogged about before. [...]

  13. The Home of BSP Training & Nutrition » Blog Archive » The Stevia Story Says:

    [...] readers are well aware of my dislike for artificial sweeteners. Whether they have been found to drastically alter gut flora (sucralose, in rats), are on the EPA’s new but unfinished list of potentially dangerous [...]

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