Artificial Sweeteners and Gut health: Should You Worry?

Image of artificial sweetener packets in a clear jar with wording artificial sweeteners and gut health: should you worry? By The Healthy RD

If you are wondering about the connection between artificial sweeteners and gut health, you are not alone.  

Many diet products and low-calorie products have some after-market safety concerns. This is despite earlier approval by the FDA and the European Food Safety Authority. 

In this post, learn about artificial sweeteners and how they can affect your gut.  

Additionally, find out better sweetener choices and how to generally cut back on added sweeteners. 

As a side note, most research studies only evaluate their effects in animal models, so the risks of them should be taken with a grain of salt. 

Also, these studies wouldn’t be allowed to be conducted in humans either. So they are the best we will ever have. 

What’s so bad about artificial sweeteners?

Unfortunately, common artificial sweeteners don’t seem to reduce the risk of gaining weight or reduce diabetes risk, their main intended purpose. 

Research also shows that they may increase your risk of heart disease and stroke too [R].

When it comes to gut health, artificial sweeteners don’t get a pass either. Generally, artificial sweeteners may change your gut bacteria more times than not as you will soon find out.    

This is a big deal because your resident bacteria help control the health of your gut lining, the health of your immune system, brain health, and more. They also can have some other negative effects on the gut too. 

Sugar doesn’t necessarily perform better than artificial sweeteners either, but are humans defeating the purpose of health by adding in chemical sweeteners?  

Disturbingly, researchers from Anglia Ruskin University recently showed that most artificial sweeteners create a biofilm with unhealthy bacteria like escherichia coli.  

This biofilm is more likely to be toxic in the body and may make bacteria more likely to invade the gut lining [R]. 

Let’s take a closer look at individual sweeteners and their risks. 


Also known by the brand name NutraSweet™ and Equal™, aspartame has gotten bad press because of its possible negative health effects on diabetes [R]. 

Particularly, these low-calorie sweeteners are linked to increased insulin resistance and increases in abdominal fat despite being a low-calorie sweetener [R, R]. 

As for the effects of aspartame on the gut, it remains a bit murky, but it’s enough for me to advise people to avoid it.  

Research also shows that aspartame impairs gut permeability [R].  

Some research additionally shows that aspartame increases the ability of bacteria to form a biofilm (not a good thing). It also shows that harmful gut bacteria may adhere to the gut lining and kill these protective cells [R]. 

A recent study showed that aspartame didn’t significantly change the gut microbiome in people consuming the sweetener for 14 days [R].

However, the use of artificial sweeteners like aspartame appears to reduce the diversity of healthy bacteria in the gut among heavy consumers of these low-calorie sweeteners [R].

Additionally, aspartame decreases an essential enzyme in the gut called alkaline phosphatase [R].  

Acesulfame potassium

One of the sugar substitutes that are not on the radar for most people is called acesulfame potassium.  Commonly added to sodas and gums, this sweetener didn’t get much media attention when it was approved by the FDA. 

Post-market research now shows that acesulfame potassium may cause gut dysbiosis and intestinal injury according to a recent mouse study [R]. 

Acesulfame potassium is not typically used as a stand-alone sweetener and is usually combined with aspartame. 

Related: 28 Chemicals in Foods to Avoid and Where to Find Them


Sucralose, also known as Splenda™, also isn’t great for the gut according to research.  By altering the microbiome, sucralose may cause untoward effects on your gut health in the long term [R, R].

Even more concerning are the possible effects of sucralose damaging the intestinal lining and possibly even leading to liver damage according to new animal research [R]. 

These effects were seen in the offspring of rats after their mothers were exposed to sucralose while pregnant.  

If it is a choice between this sweetener versus real sugar, I recommend picking a natural sweetener any day over sucralose. 


Several research studies show that saccharin has negative effects on the gut microbiome according to a review publication [R]. 

You may be thinking, “Wasn’t saccharin banned?”  Technically no. While largely taken out of the food supply, it is still out there. 

So, each time you fill up a diet soda at the gas station or in restaurants, you are getting a guzzle of saccharin. 

You also can get saccharin in diet jellies, ice creams, and confections today. 

Also, the pink pack of Sweet-n-Low™ has saccharin. 

Fact: saccharin is 200 to 700 times sweeter than sugar [R]. 

Stevia Gut Microbiome Effects

Natural isn’t always better for the gut as is the case for stevia.  Stevia, derived from stevia leaves, may also alter the gut microbiome so it’s best to make other choices for best gut health [R, R]. 

However, it still is likely a much better choice than artificial sweeteners. This is because research shows that it doesn’t spike blood sugar or cause insulin resistance and glucose intolerance like synthetic sugars do [R, R]. 

It is probably better for weight loss benefits than artificial sweeteners are as well [R]. 

Some people even use it as a natural antimicrobial and natural skin treatment, although you should not do this without the help of your healthcare provider. 

Overall safe but may be irritating to the gut 

The category of sweeteners called sugar alcohols is more natural, but their use is typically limited because it can cause GI upset, bloating, and diarrhea when they are eaten in normal quantities. 


Xylitol is considered a natural alternative to sugar, but it can be irritating to the gut.  This is because it has a laxative effect and can result in gas and bloating.  For this reason, it is best to only use small amounts of xylitol for gut health. 

It also has anti-microbial effects.

Luckily, it actually has some gut-healthy effects because it promotes the production of short-chain fatty acids, which are good for fueling intestinal cells [R]. 

Just make sure your dog doesn’t get near it: xylitol is highly toxic for dogs. 


Sorbitol can be naturally derived, but it is mostly made in a factory when used as a sweetener. 

Like xylitol, sorbitol definitely can have some laxative effects and cause some GI distress.  

Generally, I recommend people avoid using sorbitol for this reason, especially if they have irritable bowel syndrome or inflammatory bowel disease. 

Better natural sweeteners

One of the issues is that Americans like foods that are too sweet and they simply eat too many of them, artificial or not.

So, I give you better natural sweeteners here but remember, don’t overdo them either.  

They can spike your blood glucose in an undesirable way.  For this reason, it’s best to enjoy these foods in small to moderate amounts too. 

Raw Honey

Raw honey is the best sweetener for gut health for a number of reasons. First, hunter-gatherers have eaten honey as a calorie source since the dawn of time. 

Second, honey helps improve the microbiota.  Specifically, wildflower honey benefits for the gut are numerous, including prebiotics, and digestive enzymes, and has antimicrobial effects.

It also generally supports a healthy immune system [R]. 

Honey is also rich in antioxidants that support gut health.  

It is also sweeter than sugar so you can use about a third less than you would if you were using regular sugar. 

By naturally reducing sugar intake and improving gut health, raw honey is the obvious best choice as a sweetener to use. 

The only caution is for people who may have small intestinal bacterial overgrowth (SIBO).  This is because honey contains fermentable carbohydrates that may be irritating to the gut in some susceptible people. 

Real Maple Syrup

Using real maple syrup is perhaps a tie for best with honey for gut health because it contains natural prebiotics called inulin and many other healthy compounds [R]. 

Maple syrup may also reduce insulin resistance compared to sugar according to early research [R].

And, unlike artificial sweeteners, maple syrup may reduce the effects of harmful bacteria in the gut. It also reduces its chances of forming a harmful biofilm according to a recent cell study [R].  

The reason that maple syrup may help with reducing harmful bacteria is that it is rich in polyphenols, which help support healthy immune function. 

Bonus: early research shows that maple syrup may reduce the growth of colon cancer cells, although more research is needed  [R]. 

Maple syrup works amazingly well as a substitute for sugar too and the best part is that it tastes amazing.   

Coconut Sugar?

While coconut sugar is becoming popular because it is natural and much less refined than table sugar, little is known about its effects on gut health. 

You can also buy it in liquid form as coconut sap, also known as coconut nectar. 

Like maple syrup, coconut sugar contains inulin, a prebiotic for the gut [R].   

As nectar, coconut sugar is rich in minerals, including potassium at 950 mg per liter and trace amounts of zinc, iron, sodium, and magnesium [R].   

It is also rich in antioxidants, which are healthy for the digestive tract. 

Coconut sap also has moderate amounts of vitamins, including vitamin C, vitamin B1, vitamin B3, and vitamin B2. 

In conclusion, coconut sugar is better than refined sugar, but it’s important to still keep your serving sizes small. 


A smart move to improve the health profile of sweetened desserts is to use fruit as a sweetener instead of added sugars.  

One easy way to do this is to use pureed fruits like dates, prunes, apricots, raisins, or berries.  

It requires extra preparation, but it’s worth it to get the extra fiber, vitamins, minerals, and antioxidants for your gut health. 

However, if you have irritable bowel syndrome and are sensitive to any of these fruits or have diabetes, it makes sense to limit these. 

Is monk fruit the best sweetener?

In contrast to artificial sweeteners, monk fruit extract is all-natural and doesn’t have any gut side effects that artificial sweeteners do [R]. 

Traditional medicine practices even include monk fruit as a natural remedy for various health conditions and to support gut health.

Monk fruit is generally recognized as safe by the FDA.  Still, there really isn’t a ton of research about monk fruit. So it’s best to keep your intake of monk fruit low or moderate. 

Also, monk fruit sweeteners are often bulked up with other additives such as erythritol or dextrose, which aren’t necessarily gut-friendly. 

When they are present in commercial products like healthy electrolyte drinks*, however, there are no added fillers. 

*Affiliate link

Acceptable Daily Intake?

The FDA and the European Food Safety Authority don’t agree on what level of aspartame is safe.  For example, the FDA states that 50 mg/kg/day is safe, while the EFSA says that 40 mg/kg/day is safe [R].

Which one is correct?  

No one really knows, but considering all the possible health consequences and no obvious benefits, I avoid artificial sweeteners to a large degree and recommend that you do too.

The same goes for all the other artificial sweeteners.  

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body and is shared for educational purposes only. While The Healthy RD’s posts are backed by research, you are unique, so you must seek care from your own dietitian or healthcare provider. This post is not meant to diagnose or treat any conditions. Consult your doctor or healthcare provider before making changes to your supplement regimen or lifestyle.

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