Are Artificial Sweeteners Bad For Gut Health? Are There Healthier Options?

As we become more conscious of sugar’s impact on our health, alternative sweeteners have gained popularity. But while these sugar substitutes promise fewer calories and better health, could they be quietly sabotaging our gut? 

After all, there is very limited information on the long-term health impacts of noncaloric sweeteners because it’s hard to do perfectly well-controlled clinical studies on these. Some longitudinal studies have linked their intake to metabolic problems and cancers via changes in the gut flora . These correlative studies are not definitive proof that the sweeteners cause anything, but it’s good to be informed. 

In this article, we’ll explore how artificial sweeteners impact your gut and discuss some healthier options you can consider for your well-being.

Types of Sweeteners

Sweeteners are anything we use to add a sweet taste to our food or drinks and use as a sugar substitute. For this article, when I talk about sugar, I’m referring specifically to refined sugars like table sugar (sucrose) and high-fructose corn syrup, commonly found in processed foods and beverages. 

We can divide these alternatives into artificial “non-nutritive” sweeteners, natural “non-nutritive” sweeteners, and sugar alcohols.

Artificial “Non-Nutritive” Sweeteners

Artificial sweeteners are chemically synthesized sugar substitutes that provide sweetness without calories or nutrients. They are much sweeter than sugar, so only small amounts are needed.

Common artificial sweeteners include:

• Aspartame: Found in products like diet sodas and sugar-free gum
• Sucralose: Commonly used in baked goods and diet drinks, known as Splenda
• Saccharin: Found in sweeteners like Sweet’N Low
• Acesulfame potassium (K): Often used in combination with other sweeteners in sugar-free products

Natural “Non-Nutritive” Sweeteners

These are plant-derived and offer sweetness without significant calories, making them popular choices for health-conscious consumers.

Popular natural sweeteners include:

• Stevia: derived from Stevia rebaudiana leaves
• Monk Fruit Extract: From Luo Han Guo, much sweeter than sugar
• Thaumatin: A protein derived from the katemfe fruit found in West Africa. Thaumatin is extremely sweet—up to 3,000 times sweeter than sugar

Sugar Alcohols

Sugar alcohols are carbohydrate-based sweeteners with fewer calories than sugar and are commonly used in sugar-free or low-sugar products. They tend to be extracted or purified from natural sources.

Some common sugar alcohols include:

• Xylitol: Naturally found in fruits and vegetables and often used in gum and oral care products
• Erythritol: Made from fermented corn, this sweetener is nearly calorie-free and commonly used in sugar-free protein bars
• Sorbitol: Made from potato starch and is often used in sugar-free candies and baked goods
• Maltitol: Produced from cereal starches like corn and potatoes and often used in sugar-free chocolates, candies, and baked goods

How Do Artificial Sweeteners Affect Gut Health?

Your gut flora is constantly in flux, and what you eat plays a key role in shaping its composition. While opting for artificial sweeteners instead of sugar might seem healthier, let’s explore whether they could work against your goals.

Changes in Gut Composition

While the results differ depending on the type of artificial sweetener, a review of studies sheds light on their potential effects on gut composition. With the field dominated by animal studies, it does present challenges to fully understand the effects on humans, but also opens up intriguing possibilities for further exploration. 

To understand the nuances, let’s examine the specific effects of some of the most common artificial sweeteners on gut bacteria.

Acesulfame K

In animal studies, acesulfame K’s impact on gut flora depends on the dose. At the acceptable daily intake (ADI) of 15 mg/kg (6.8 mg/lb), gut bacteria were minimally affected. In contrast, a higher 37.5 mg/kg (17 mg/lb) dose caused significant changes, including increased Bacteroides in male mice and decreased Lactobacillus in female mice.

These sex-specific effects suggest acesulfame K influences gut microbiota differently based on dose and gender, though higher doses may not reflect typical human intake.

Aspartame

Animal studies with aspartame suggest it may significantly alter gut composition. Eating sweeteners did not change the number of different bacteria types, but it did change their quantities. There was a decrease in beneficial Odoribacter bacteria and a significant change in the Bacteroides and Firmicutes balance.

It’s hard to know more about the effects of aspartame on the human gut because researchers believe it breaks down quickly in the small intestine into components that are absorbed and do not reach the large bowel. Therefore, it’s possible that, unlike in animals, human gut bacteria is not affected by aspartame. 

Saccharin

Saccharin, with the lowest ADI of 5 mg/kg (2.2 mg/lb), might pose more trouble for gut bacteria than other artificial sweeteners. Based on the review of animal studies, researchers found that saccharine can lead to gut microbiota changes, including reducing certain bacterial strains such as Clostridium and altering microbial composition, which may lead to dysbiosis or unhealthy gut composition.

In a six-month animal study, mice consumed a dose of saccharin equivalent to the acceptable daily intake. Researchers observed alterations in gut bacteria linked to liver inflammation, and the mice also showed increased liver inflammation.

Saccharin doesn’t seem to discriminate between good and bad bacteria. Another animal study found that saccharine inhibited both Lactobacillus and E. coli growth. 

A study in healthy adults found different effects on gut flora. Participants took the maximum daily dose of 400 mg of saccharine for two weeks. Those taking saccharin did not experience significant changes in gut microbiota.

While these results are more hopeful, it’s important to note that this study was very short. It would be helpful to know more about the impacts over time, like in animal studies. 

Sucralose

Finally, let’s look at sucralose, which has an ADI of 5 mg/kg (2.2 mg/lb). Animal studies suggest that sucralose consumption alters gut function. After taking sucralose for 12 weeks, rats had a more than twofold reduction in Bifidobacteria, Lactobacilli, Bacteroides, and Clostridium levels.

In a more extended six-month study, mice consumed the equivalent of the ADI of sucralose. Researchers observed a change in 14 different categories of gut bacteria, showing a wide range of effects. These changes were associated with increased inflammation in the mice.

Human studies, once again, paint a different picture. One study in humans involving 34 healthy men investigated the short-term impact of sucralose on gut bacteria. Researchers divided participants into two groups: one received sucralose capsules and a placebo for seven days. There were no significant changes in the composition of gut bacteria.

Other Effects On The Gut

The effects of artificial sweeteners on the gut aren’t limited to microbiota changes. They also extend to the structure and function of your gut lining.

A study explored the effects of a relatively new artificial sweetener, neotame, on the intestinal epithelium. This layer helps you absorb nutrients from your food and protects your body by preventing bacteria and toxins from entering your bloodstream. Researchers exposed epithelial cells to neotame in the test tube.

Epithelial cells exposed to neotame died faster, which could eventually weaken your intestinal barrier. Neotame exposure also reduced claudin-3, a protein that helps keep the cells in the intestinal barrier tightly packed together.

Artificial sweeteners may also increase the harmful activities of some gut bacteria, making them more likely to damage gut cells. Researchers exposed gut bacteria E. coli and E. faecalis to artificial sweeteners saccharin, sucralose, and aspartame.

The sweeteners helped bacteria stick together and form a protective layer called a biofilm. When tested with human gut cells, the bacteria became better at sticking to, invading, and damaging these cells.

Like most things, there is an individual response to artificial sweeteners. It probably also matters how long you use them. Some studies cover use for only seven days. But what if you use them daily or at least regularly? We need more research to understand the long-term effects better. 

Potential Metabolic Effects 

The effects of artificial sweeteners aren’t limited to the gut. Changes in gut bacteria can affect other metabolic functions, like how your body processes sugar, controls hunger, and manages fat storage.

Blood Sugar Control

A great starting point to demonstrate the relationship between gut bacteria and blood sugar is the human study on sucralose consumption. After consuming sucralose for seven days, while there were no changes in body weight or blood sugar control, the study did uncover an intriguing detail.

After the intervention, people with higher insulin levels had different gut bacteria, whether they consumed sucralose or not. This suggests that personal metabolism may impact sucralose’s effect on gut bacteria, highlighting the need for personalized sweetener strategies.  

This is important because it shows that sweeteners like sucralose don’t affect everyone equally. Factors like individual metabolism can influence how your gut bacteria respond, impacting your overall health, especially in areas like digestion, blood sugar control, and weight management. 

In the review of studies on sweeteners, researchers came to a mixed conclusion regarding their effects on blood sugar. Some were more concerning than others.

Animal studies link saccharin consumption to poor blood sugar control. Researchers believe this happens because, as we already discussed, saccharin changes gut bacteria’s balance, affecting how the body processes sugar. These changes can reduce the body’s ability to handle glucose properly, leading to higher blood sugar levels and possibly increasing the risk of poor blood sugar control.

The review highlighted the specific gut bacteria changes after artificial sweetener consumption, such as a rise in Bacteroides and a drop in Clostridiales, associated with poor blood sugar control. Clostridiales help break down certain sugars into short-chain fatty acids like butyrate, which can improve insulin sensitivity and help regulate blood sugar levels. A drop in them may lead to poor blood sugar control.

Another review echoed the previous suggestion that people respond differently to artificial sweeteners due to variations in their gut bacteria. While initially intended to help with weight and blood sugar control, the findings indicate they may contribute to the opposite for some people.

Hunger

Some people consume artificial sweeteners to support weight loss, but are they undermining you by increasing your appetite? Part of this answer is tied to blood sugar control. Your blood sugar levels play an important role in modulating hunger.

A review of studies explored the effects of sweeteners on hunger and weight loss. While the response still seems individual, some studies found that consuming artificial sweeteners could lead to poor blood sugar control, affecting hunger-regulating hormones and leading to frequent cravings and overeating.

One reason could be tied to cephalic phase insulin release, an early insulin response triggered by tasting or even thinking about food. This surge helps prepare the body for increased blood sugar from eating. When artificial sweeteners trigger this response without adding calories, it may disrupt blood sugar regulation, making you hungrier or crave more foods.

Artificial sweeteners may also influence hunger by activating the brain’s reward system, which regulates eating behavior. This system can promote food intake by providing pleasure, potentially affecting hunger and eating habits. Sweet-tasting foods, including those made with artificial sweeteners, strongly stimulate this reward system, which may lead to overeating even after meeting your energy needs.

In a contrasting clinical trial, results suggest they do not increase appetite. A study of 53 overweight but otherwise healthy adults explored the effects of sweeteners on appetite. Participants consumed cookies sweetened with either sugar, neotame (an artificial sweetener), or stevia for two weeks.

After eating the biscuits, participants rated their fullness over the next few hours. Researchers checked their blood glucose levels and several hormones related to hunger and digestion. There were no differences between the sweeteners and sugar on appetite. There were differences in blood sugar levels, with the sweeteners being lower than those who consumed sugar.

Again, whether or not artificial sweeteners are a good option for you seems to depend on your body’s response. We don’t metabolize each sweetener the same way; everyone is different. Either way, it’s probably best to stick to minimal amounts.

Are Other Sweeteners Better for Gut Health?

With artificial sweeteners raising concerns, many are turning to natural sweeteners to see if they offer a healthier alternative. 

Natural “Non-Nutritive” Sweeteners

Natural sweeteners support more stable blood sugar levels than artificial sweeteners. Let’s examine how they can impact your gut. 

Stevia

While the aftertaste of stevia can be a bit off-putting for some, it’s still likely a better choice than artificial sweeteners for your gut.

The breakdown of stevia in the body relies on the bacteria in the gut with special enzymes that can convert stevia’s components, called glycosides, into a substance known as steviol. Once stevia is broken down into steviol by these gut bacteria, the body can absorb it.

Naturally, with this kind of interaction, consuming stevia might affect gut bacteria. Lab studies show that some bacteria, like Bacteroides, are good at breaking down stevia. One compound in stevia, stevioside, seems to slightly inhibit anaerobic bacteria, which make up 99% of the bacteria in your gut.

Another study dug a little deeper into the exact effects of stevia on the gut via lab studies. Overall, researchers believe that consuming stevia might help increase the variety of bacteria in the gut, known as alpha diversity.  

Stevia seems to be a good choice for other metabolic effects. A study of 28 healthy adults explored its impact on blood sugar. Participants consumed five drops of stevia twice daily or no supplement for 12 weeks and were instructed to maintain their usual diet. There was no significant difference in blood sugar levels between the groups.

However, the stevia group maintained weight, while the control group gained weight. Unlike the control group, the stevia group also significantly reduced their energy intake over 12 weeks. Therefore, stevia may help maintain weight and reduce calories without affecting blood sugar.

Stevia is a plant in the same family as dandelion and sunflower, so those with ragweed allergies may also have allergies to raw stevia.

Monk Fruit

If you just can’t get past that stevia aftertaste, monk fruit is another natural sweetener with promising effects on your gut.

This is what we know about how your body processes it. The compounds in monk fruit that give it its sweetness, known as mogrosides, are broken down in the human intestine by enzymes and gut bacteria into simpler compounds that are easier for the body to digest and absorb. Most mogrosides exit the body through urine, while products produced when broken down appear in the feces. Small amounts are also present in the blood and organs.

Human studies focus on the effects of monk fruit on blood sugar levels. An analysis of two studies found that consuming 200 mg/kg (90 mg/lb) had no effect on blood sugar levels, and there were no adverse effects. It’s important to note that these studies focused on a one-dose response and not over time. 

Animal studies suggest that mogrosides in monk fruit can help modulate the inflammatory response by altering gene activity. A well-regulated inflammatory response is beneficial for the gut because it can otherwise disrupt the balance of gut bacteria and damage the intestinal lining.  

Thaumatin

Like monk fruit, thaumatin, which has GRAS (Generally Recognized As Safe) status and has been consumed for over one hundred years by humans in West Africa, is unlikely to adversely affect gut health. According to an FDA report, it has no potential toxic effects and contains easily digestible proteins. 

One study exploring the effects of sweeteners on human fecal samples found an interesting result for thaumatin. Unlike other sweeteners, thaumatin increased the total amount of microbial cells in all five gut microbiotas studied. This suggests that thaumatin may promote microbial growth or activity in these environments.

Again, without more human studies, it’s hard to tell what this means exactly and how going through the digestive process might change these results and your experience with the sweetener. 

At BIOptimizers, we incorporate both thaumatin and monk fruit in our products. These natural sweeteners taste great and align with our commitment to high-quality, health-conscious ingredients.

Sugar Alcohols

If you’ve consumed sugar alcohols before in some of your favorite sugar-free snacks, drinks, and keto-friendly protein bars, it probably won’t surprise you to know that these do affect your gut. 

Eating too many polyols can cause digestive issues like gas or a laxative effect, similar to what some people experience with beans or high-fiber foods. How much this affects you depends on your sensitivity and what else you’ve eaten. (Livesey, 2003) 

If you avoid FODMAPs, note that sugar alcohols are the “P,” you should also avoid these, although erythritol may be okay. 

Erythritol

The good news for erythritol is that, unlike other sugar alcohols, it’s much less likely to cause diarrhea. This is likely because it’s quickly absorbed by your small intestine and excreted through your urine, skipping over your large intestine entirely.

Because it skips over your large intestine, there are no known effects on gut bacteria. Additionally, based on current evidence, it does not seem to influence blood sugar at all.

While erythritol seems promising, a study raises some concerns about weight gain. A nine-month study of over 250 university students examined blood samples to find markers linked to weight gain around the belly. It found that those who gained weight had much higher levels of erythritol in their blood than those who didn’t.

While researchers are still exploring the potential connection between erythritol and weight gain, they suggest it may influence metabolic pathways related to fat storage. Although you don’t metabolize erythritol after consumption, it’s converted to erythronate, which might affect metabolism and weight gain.

Xylitol

Xylitol is typically only partially absorbed in the upper small intestine, with significant amounts reaching the lower part, depending on how much you consume. In drinks, however, xylitol isn’t as well absorbed in the small intestines and is more likely to reach the colon. 

A review of studies found that xylitol reduced Bacteroidetes and increased Firmicutes in mice, with a similar shift observed in humans after a single 30 g dose. Some, but not all, studies have linked Firmicutes to weight gain. However, neither group is inherently good or bad—both Firmicutes and Bacteroidetes contain beneficial, harmful, and neutral species. What is most important is balance. 

Researchers also note xylitol’s prebiotic potential, stimulating the growth and metabolic activity of beneficial bacteria like Anaerostipes in the human colon. When taken with probiotics, xylitol also protects against C. difficile in mice.

Natural Sweeteners (That Contain Sugar or Nutrients)

If you’re not trying to avoid sugar, you may also be wondering how other natural sweeteners stack up when it comes to gut health. We want you to be able to make the most informed decisions, so let’s take a quick look. 

Honey

Honey has both prebiotic and probiotic potential when it comes to gut health. 

A review of studies explored honey’s potential. The majority of research to date is lab studies using fecal bacteria. Overall, honey seems to stimulate the growth of beneficial gut bacteria while inhibiting the adherence of harmful bacteria like Salmonella to intestinal cells, suggesting a protective role.

They also note that the effects of honey depend on the floral source, which can change the carbohydrate makeup. Clover honey increases multiple strains of Bifidobacterium, while manuka honey increases both Lactobacillus and Bifidobacterium while inhibiting harmful bacteria like E. coli, Salmonella, and Staphylococcus aureus.

Darker honey tends to support a healthy inflammatory response better than lighter ones.

Adding honey to your yogurt might help probiotics survive digestion, supporting your gut health. In a study simulating digestion, researchers combined different types of honey—alfalfa, buckwheat, clover, and orange blossom—with yogurt and measured how well the probiotic B. animalis survived.

Clover honey significantly enhanced the survival of B. animalis compared to other types of honey and control groups. Using more clover honey led to even better probiotic survival.

For the greatest benefits, raw honey is best, and don’t heat it beyond 90°F (32°C).

Maple Syrup

Compared to sugar, maple syrup positively affects the gut. An eight-week study explored maple syrup’s effects on gut bacteria and metabolic factors. Compared to sugar syrup, those consuming maple syrup had improved blood sugar control, reduced belly fat and blood pressure, and positively altered gut bacteria.

The improvements in gut composition may be because maple syrup contains polyphenols and inulin, which feed healthy gut bacteria.

Agave Nectar

The key to gut health with agave lies in its agavins, which are prebiotic compounds that may enhance gut health by promoting the growth of beneficial bacteria.

A review of animal studies provides insight into the benefits of agavins. Researchers found that consuming avagins increased the growth of healthy bacteria Bifidobacterium, Lactobacillus, and S. Boulardii in mice. Agavins may also influence the production of short-chain fatty acids, which are crucial for gut health, by affecting the composition and activity of gut bacteria.

The problem, however, is that when turning agave sap into agave nectar, gut-friendly agavins are extracted and broken down into fructose through heating or enzymatic treatment.

Agave nectar is very high in fructose – about 85%, which makes it difficult for your liver to break down, possibly leading to poor blood sugar control and weight gain.

Date Sugar

Date sugar, made from ground dehydrated dates, is rich in polyphenols and fiber.

In a study involving 22 healthy participants, researchers explored the effects of dates on gut bacteria. Participants consumed seven dates daily for 21 days. While date consumption didn’t significantly alter gut bacteria or short-chain fatty acid levels, it did improve bowel movements and reduce ammonia levels in stools, suggesting better overall bowel function.

Coconut Sugar

Coconut sugar, rich in minerals and antioxidants , may benefit overall health, including gut health, by supplying essential nutrients that help maintain a balanced gut microbiome. 

Coconut sugar, with its low glycemic index of 35, helps stabilize blood sugar levels, which may support a healthy inflammatory response and support healthy digestion—key factors for gut health. Additionally, coconut sugar contains a small amount of inulin, a prebiotic fiber that may nourish beneficial gut bacteria.

Inulin

Inulin, a water-soluble fructan (yes, that falls under “f” in FODMAP), serves various functions in addition to natural sweetener. It’s also used in food to replace fat and boost fiber.

A review of studies highlighted the benefits of inulin on gut health. Inulin acts as a prebiotic, fermented by beneficial bacteria in the colon to support a healthy gut microbiome. This fermentation helps manage constipation by drawing water into the colon and promoting regular bowel movements. Additionally, as a dietary fiber, inulin aids digestion and enhances mineral absorption, indirectly supporting overall gut health.

A placebo-controlled study of 150 overweight patients explored the effects of inulin on gut flora. Participants consumed 16 g of inulin daily for three months. Those taking inulin experienced a notable increase in Actinobacteria and Bifidobacterium.

Those who consumed inulin showed a reduction in insulin levels. While the change wasn’t statistically significant, it indicates potential improvements in insulin sensitivity. Better insulin sensitivity allows the body to manage blood sugar more efficiently with less insulin, which benefits overall metabolic health.

Glycine

If you recognized glycine as an amino acid, you’d be correct. This one just happens to be sweet. It’s also a calming neurotransmitter and a key component of collagen. Per gram, it’s less sweet than glucose and fructose, and has 3 – 4 calories per gram.

Animal studies suggest that glycine supports the gut lining by protecting intestinal epithelial cells from oxidative damage.  It may also strengthen tight junctions in the gut, which are key structures that help maintain the integrity of the intestinal barrier. Tight junctions seal the spaces between gut cells, preventing harmful substances from leaking into the bloodstream and ensuring proper nutrient absorption, which is crucial for overall gut health.

The benefits of glycine extend to blood sugar control. A placebo-controlled study of nine healthy subjects explored the effects of glycine supplementation on blood sugar response. Subjects took either glycine, glucose, or a combination of glycine and glucose while researchers monitored their blood sugar response.

Participants who consumed glycine alongside glucose experienced 50% lower blood sugar response than those who consumed glucose alone. Interestingly, when glycine was taken by itself, participants showed increased insulin and glucagon levels, suggesting a potential impact on blood sugar regulation.

Conclusion

Ultimately, artificial sweeteners affect everyone differently, and their long-term impacts on gut health are still being studied. If you’re looking for a safe bet, natural sweeteners like stevia, monk fruit, and thaumatin may offer fewer risks and even some potential benefits. That’s why we chose these for our BIOptimizers products. 

But as always, moderation is key—listen to your body and choose what works best for you.

And when you want to go all in and get your sweet fix, ease your guilt by taking Berberine Breakthrough, designed to help support a healthy gut and help maintain healthy blood sugar levels already within a normal range.