Spilling the Tea on Splenda / Sucralose and IBS

Splenda® (Sucarlose) and IBS

Splenda®, or “sucralose”, is a Food & Drug Administration (FDA)-approved artificial sweetener which entered the mainstream food system in the United States back in the late 1990’s.  Along with its sugar substitute counterparts including saccharin, aspartame (now labeled as “amino sweet”), and a handful of other artificial sweeteners, sucralose has been hit with a lot of controversy in the field of gut health and irritable bowel syndrome (IBS).  But if sucralose is FDA-approved, and it’s being sold in millions of supermarkets, can it really be that bad?  In this article I’ll spill the tea on Splenda® / sucralose and IBS, from my perspective as a gut health expert, holistic nutritionist, and functional dietitian nutritionist.

(Updated July 11, 2022)

Disclaimer:  I’ve chosen to share these findings to help educate the general public on some important information that isn’t shared very openly.  Please use this blog post for educational / informational purposes only.  Also, make sure you consult a licensed health professional individually if you have any type of medical condition!

What is sucralose?

Sucralose is the chemical compound which makes up Splenda®, an FDA-approved, no-calorie sugar substitute that has made its way into millions of cups of coffee and sweet treats each day since 1998.  Splenda® has also made a big debut in the confectionary world, since it can be used as a 1:1 replacement for table sugar in most recipes.

This chemical sweetener is ~600x sweeter than sugar. (2) which makes it extra appealing for people who would like to reduce sugar intake for one reason or another!

Splenda® seems to be most popular among people with diabetes and those who are dieting to lose weight, based on over a decade of my first-hand experience in clinical nutrition settings.

How is sucralose different from sucrose (table sugar)?

Chemically speaking, the only difference between sucrose and sucralose is three chlorine atoms (3).  In a nutshell, sucralose is essentially sugar with chlorine added to it so that your body won’t metabolize it as real sugar.

  • Sucralose is categorized as a C3 chlorocarbon, because three hydrogen atoms from the original molecule (table sugar) have been replaced with three chlorine atoms (4).
    • Other examples of chlorocarbons include chloromethane, trichloromethane, and trichloroethylene which are frequently used in a variety of cleaning and de-greasing products (4, 5).
  • You may also recall that chlorine (in larger quantities) is used to sterilize swimming pools.

What is IBS?

IBS is a functional gut disorder – aka a chronically sensitive or upset stomach, for what may seem like no rhyme or reason.

IBS is officially diagnosed after other gastrointestinal medical conditions such as celiac disease, small intestinal bacterial overgrowth / “SIBO”, Crohn’s diease, colitis, diverticulitis etc. have been ruled out by your doctor.

Some of the most common signs and symptoms of IBS include, but are not limited to:

IBS plagues millions of people worldwide.  While more research is needed, IBS seems to link back to an imbalance in gut microbes, aka “dysbiosis”. (1)

Now, let’s talk about how gut microbes and IBS are impacted by nutrition and diet!

Nutrition, IBS, and the microbiome

As IBS research continues to unfold, it’s become well established that what we eat and don’t eat can make-or-break the way our gut functions. This is because certain foods and chemicals we ingest seem to interact with the gut microbiome in ways that either help it or hurt it.

  • A “gut microbiome” is a fancy way to describe each person’s individual ecosystem of bacteria, fungi, and viruses living in the gut.  The microbes living in our gut impact the way we to digest and absorb nutrients from food.
  • Our gut microbiome also plays a powerful role in determining the state of our intestinal cells that make up the gut lining.
  • Everyone’s microbiome is as unique as our fingerprints!  No two are the same.

While everyone’s nutritional needs are unique and individualized, there’s been a good amount of overlap in how some foods impact our gut health and IBS for better or worse.

For the purpose of this article, let’s answer some burning questions you may have about sucralose and gut health!

Sucralose and the gut 

While more research is needed in humans, so far, animal studies are showing that sucralose seems to have a significant impact on gut microbes.  There are also lots of indirect human studies linking the relationship between gut microbes, gut pH and IBS.  (This is where it gets confusing: some people believe the studies we have on sucralose thus far are relevant to us humans, while others disagree.)

Below is a recap of what I found while nerding out on sucralose and gut microbes, for your reference! 😎

Sucralose may reduce probiotic bifidobacteria levels in the gut

A Duke University study on Splenda® in 2008 found that daily intake of Splenda®, in amounts 4-5x lower than the U.S. FDA Acceptable Daily Intake levels, for 12 weeks straight, resulted in a decrease in probiotic gut microbes including bifidobacteria in rats (6).

Sucralose may reduce acidity in the gut

The same 2008 Duke study also observed that 12 weeks of daily sucralose consumption led to a higher “fecal pH” (6) which means sucralose may on some level contirbute to an envionment in the gut called “hypochlorhydria” (low stomach acid).

Gut pH, dysbiosis, and IBS / SIBO

Reduced acidity levels in the gut are known to create an environment where “bad”, troublesome, pathogenic microbes may grow out of control if left unchecked. (7).  This may explain why people with IBS and/or SIBO tend to have a higher gut pH (lower acidity level).  (8

Long story short, sucralose reduces stomach acidity to a certian point – although not to the same degree as acid blockers and “proton pump inhibitors” like Prilosec and Nexium, which are also linked to IBS and SIBO. (9, 10)

Sucralose in your food: where does it hide?

Even if you don’t bake wtih Splenda® or add it to your morning brew, chances are you could still be consuming traces of this artificial sweetener without even realizing it.  Splenda® and lots of other artificial sweeteners (like sugar alcohols) which can also impact IBS are often hidden in “health foods” and diet foods.

For example, some of the most common foods that contain sucralose include, but are not limited to:

  • Protein powders
  • Protein bars
  • Protein shakes
  • Pre-workout drinks
  • Low-fat, low-sugar flavored yogurts
  • “No sugar added” versions of sweets
  • Other diet foods
  • “Diabetes-friendly” baked goods

How to find it on an ingredient list

You’ll usually see Splenda® listed as “Sucralose” at the end of an ingredient list on a nutrition label.  (Ingredients are listed in descending order from highest to lowest, based on how much of each ingredient is included in a serving of the food product.)

Quest bar ingredient list - contains sucralose

Is sucralose high or low FODMAP?

FODMAPs, or “fermentable oligosaccharides, disaccharides, monosaccharides and polyols”, are specific types of carbohydrate molecules in foods which are known to feed certain types of bacteria in the intestines, leading to fermentation.  This fermentation in the intestines is what leads the microbes to product methane gas as a bi-product. (I know… yikes!)

  • What this translates to: certain types high FODMAP foods are likely to produce methane, triggering symptoms of gas and bloating among many people with IBS.

So where does sucralose stand as a sweetener on the FODMAP spectrum?

Surprisingly, sucralose is considered low FODMAP, meaning it doesn’t contain any of the carbohydrate constiuents which feed the “bad” gut microbes that ferment and produce methane in the intestines.

At the same time, just because a food (or food-like substance, in this case) is considered “low FODMAP” doesn’t mean it’s a good option for people with IBS! Going on a low FODMAP diet protocol is not going to do much for your IBS if you don’t also address your gut health via a multi-dimensional approach.

  • If you’re feeling a bit lost and would like some more guidance on how to navigate your IBS from a holistic standpoint, I invite you to download my free gut health nutrition guide where I share 5 of the most common dietary mistakes I see people making with IBS. 

Free Download - 5 Diet Mistakes to Avoid When Healing Your Gut - by Jenna Volpe RDN LD CLT

So, is sucralose good or bad for IBS and gut health?

In the complex field of nutrition and health, nothing is ever black and white, right or wrong.  Health professionals don’t always see eye-to-eye when it comes to what we’re putting (or not putting) in our bodies, because research findings can be easily skewed, manipulated, inconsistent, and/or misleading. 

Needless to say, there’s a decent amount of research showing that sucralose alters the gut based on animal studies. And while some pracititoners think it’s significant, others seem to minimize what I’m about to share!

I’ll let YOU decide what you’d like to believe about sucralose and IBS / gut health based on the above information shared in this article.

Related articles

To learn more about sweeteners and IBS, you may also want to check out the following articles:

Sucralose and IBS: conclusions

It remains controversial among healthcare providers whether or not sucralose is harmful to people with IBS.

From an acute, clinical standpoint, sucralose does not seem to trigger flares among people with IBS.

  • For example, many registered dietitians who specialize in IBS endorse sucralose because it’s low FODMAP and FDA-approved.
  • But just because a sweetener is low FODMAP doesn’t mean it’s not harmful to the gut microbiome or gut pH.
    • A low FODMAP diet is very restrictive, not customized, and not a long-term solution for IBS beyond helping with symptom management.  We must take into account the full picture of the gut microbiome, and we also need to make sure we’re nourishing and supporting the gut in ways that are conducive to healing.

All of that said, from a chronic health and functional medicine standpoint, on the cellular level, sucralose may not be your best ally if you’re looking to manage your IBS holistically.

Looking at the big picture and putting two and two together from a holistic lens, we know the following to be true:

  • Dysbiosis is found to be a common underlying root-cause of IBS.
  • Sucralose contains chlorine which is used in larger quantities to sterilize swimming pools.
  • Sucralose consumed in modest quantities daily over 12 weeks has been shown to substantially lower the count of Bifidobacteria in rats.  Bifidobacteria are a strain of probiotics deemed generally healthy and essential in the human gut microbiome.
  • Too-low levels of gut acidity seem to create favorable conditions for troublesome microbes to over-grow in the gut.  Studies have revealed to us that sucralose may reduce stomach acidity to a certain extent.

As I mentioned earlier, there’s still a need for more human studies on sucralose.  This may be why many well-respected nutrition providers are still framing the research in such a way that “data is limited” on the impact of sucralose and human gut microbes.

  • From a mindset standpoint, if someone is only being told “there isn’t enough research to say that sucralose is bad for gut health”, and that it’s low FODMAP, but the other studies are not being disclosed, they may feel more inclined to believe sucralose is harmless for IBS.

Given all of the above, I’m personally not a fan of sucralose for people with IBS or for anyone in general. But that’s my opinion, based on my clinical judgment from a holistic perspective!  There’s lots more I could say about sucralose. The research is ever-evolving, and the studies I referred to in this article are not exhaustive – they skim the tip of the iceberg.

Please always listen to your gut (pun intended), do your research, and consult a holistic-minded gut health dietitian if you need extra support navigating your IBS from a nutrition standpoint.

If you found this article helpful, feel free to share it with a family member or friend who eats Splenda often, and/or is navigating IBS and would like to learn more!

XO – Jenna

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