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Xylitol Side Effects: Safe or Dangerous?


Xylitol side effects - Dr. Axe

If reading food labels is part of your shopping experience, you’ve probably seen the ingredient “xylitol” coming up more and more the past couple years. Reported by most manufactures as being “all natural,” few suspect it’s anything but healthy. Unfortunately, natural doesn’t always mean “non-toxic.”

To make matter worse, the reports on the Internet have been anything but clear, and people ask me quite regularly about whether xylitol has been proven dangerous or beneficial to our health. So I have researched the xylitol side effects to find out whether this artificial sweetener is really safe or not.

In reality, there is no simple answer, and after careful research, I have come to the following conclusion: Using xylitol may be beneficial for oral health, although it’s not safe for consumption in large amounts. 

Why? The key lies in understanding what xylitol is.

What Is Xylitol?

Xylitol is a sugar alcohol, which is a low-digestible carbohydrate that resists starches and includes fiber. Recently gaining ground in many health circles because of the claim that sugar alcohols are “natural,” other varieties you’ve probably seen in the stores include:

  • Erythritol
  • Isomalt
  • Lactitol
  • Maltitol
  • Mannitol
  • Sorbitol

Considered a crystalline alcohol, xylitol is actually a derivative of xylose — a crystalline aldose sugar that is not digestible. Xylose, not xylitol, is naturally found in nature as it is mostly obtained from birch bark. Yet, just because something is “natural” doesn’t mean that it is good for you. I stress this because, ever since research conducted in the 1950s, it has been known that: (1)

  • Single-stomach animals are unable to properly metabolize xylose.
  • People who eat foods with xylose tend to experience digestive issues like gas, bloating and diarrhea.
  • Liver evaluation suggests that xylose gets stored in the body.

When foods that are eaten are normally digested, nutrients, like vitamins and minerals, are absorbed into the bloodstream in the small intestine. However, when chemical compounds like xylitol are consumed, the body cannot utilize them so they travel through your GI tract relatively unscathed.

Sometimes, these chemicals can react with the other foods that you eat, the enzymes that your pancreas produces or other “gastric juices” and cause complications. In the case of xylitol, this is generally experienced as gastrointestinal disturbances.

In spite of the research conducted since last century, I believe that this statement from a 1952 article published in the Journal of Nutrition still rings true: (2)

Pending more favorable experimental data at lower levels of intake, it is deemed inadvisable to risk the incorporation of xylose in foods at any level of intake for extended periods of time.

Are Xylitol Side Effects Dangerous?

Xylitol poisoning is relatively unheard of in humans, and the xylitol side effects associated with consuming it are generally minimal for most people. However, it has been reported that xylitol can raise blood glucose levels, which suggests that diabetics shouldn’t consume it. (3) This may seem odd to most people as many doctors recommend that people use it to replace sugar because it’s low on the glycemic index.

Another concern that I have with xylitol is the industrialization process that is used to manufacture it. Currently, most xylitol is produced by “hydrogenating” xylose, a chemical process that treats a compound with hydrogen usually with a catalyst, such as nickel. There are two major problems with this process.

First, the fact that xylitol is “hydrogenated” should raise some concerns because hydrogenated foods are known to cause:

  • Alzheimer’s disease
  • Behavioral irritability and aggression
  • Cancer
  • Diabetes
  • Obesity
  • Liver dysfunction
  • Major depressive disorder

Secondly, nickel is a known toxin has been linked to: (4, 5)

  • Asthma attacks
  • Cancer
  • Dermatitis (skin allergies)
  • Hand eczema (skin rash)
  • Indigestion
  • Kidney problems
  • Lung disorders

At this point, there is no research proving that chewing xylitol-sweetened gum or eating xylitol-sweetened cookies will cause these things, but I’d be careful before diving in and making xylitol part of your daily natural health regimen.


Xylitol side effects - Dr. Axe

A Special Warning to Pet Owners

On a very important side note, for all of my friends out there with pets, xylitol side effects are very toxic to pets. In fact, “xylitol is extremely toxic to dogs,” according to VCA Animal Hospitals. (6) For instance:

  • One animal poison control organization in Minneapolis received more than 1,500 calls for xylitol poisoning.
  • When non-primate species eat xylitol, it’s absorbed into the bloodstream quickly and releases a potent amount of insulin rom the pancreas.
  • “This rapid release of insulin results in a rapid and profound decrease in the level of blood sugar (hypoglycemia), an effect that occurs within 10–60 minutes of eating the xylitol. Untreated, this hypoglycemia can be life threatening.”

Be sure to read your pet’s food labels, and never feed pets your table scraps if they have xylitol in them.

Xylitol Side Effects

The reason sugar alcohols like xylitol are not recommended for human consumption is because of the twofold metabolic xylitol side effects that burden the body and lead to weight gain:

  1. First, because the body cannot digest them properly, the non-metabolized portion ferments and creates a favorable environment for harmful bacteria to colonize. Exacerbating yeast problems, many people will also experience constipation, gas/bloating and diarrhea. (7)
  2. Second, as with all toxins, because the body cannot digest them sufficiently, precious metabolic resources are wasted in an attempt to clear it out of your digestive system and can thus cause unwanted weight gain.

According to one report, the key to the xylitol side effects is in its dosage. Xylitol side effects when exceeding 40–50 grams per day include: (8)

  • nausea
  • bloating
  • borborygmi (rumbling sounds of gas moving through the intestine)
  • colic
  • diarrhea
  • increased bowel movements

Next to minor GI complaints, weight gain is the most heavily researched side effect to consuming xylitol and other artificial sweeteners. In addition to the metabolic burden they place on the body, there is a psychosocial aspect that cannot be ignored. According to Harvard Medical School experts, “Research raises concern that they may do just the opposite and actually promote weight gain. How so? [Alternative] sweeteners are extremely sweet — hundreds to thousands of times sweeter than table sugar.” (9)

What happens is people who consume sweeteners habitually become desensitized to sweetness so much so that unsweetened, healthy foods become unappetizing. This can lead to a less healthy diet, avoiding foods that provide satiety and instead filling up on empty, unhealthy calories from sweetened products. The experts go on:

In addition, some research has identified sweetness receptors in fat tissue. We don’t know for sure, but that raises the possibility that [alternative] sweeteners could cause weight gain by directly stimulating the development of new fat cells.

There’s also some epidemiologic evidence of a correlation between [alternative] sweetener consumption and obesity, but it should be interpreted cautiously. People might consume [alternative] sweeteners because they’ve gained weight, not the other way around.

Xylitol Benefits

One of the beneficial xylitol side effects seems to be its ability to improve oral health. This appears to be widely held by most health care professionals. In fact, the dental community is one of its biggest supports because of xylitol’s reported ability to prevent cavities.

For example, according to a study published in the Journal of Dental Education, “The replacement of sucrose with sorbitol and xylitol may significantly decrease the incidence of dental caries.” (10)

A 2009 article published in the European Journal of Dentistry provides some details as to why: (11)

Xylitol has beneficial effects on the oral flora not shared by other polyols. The evidence so far supports specific xylitol-effects on oral bacteria, but not on saliva. Xylitol cannot be metabolized by plaque bacteria, contrary to sorbitol and other 6-carbon polyols, and may thus favor mineralization.

Interesting, there are conflicting reports, and we cannot jump to the conclusion that xylitol is completely effective at keeping cavities at bay. In the words of a frequently cited review in the journal Caries Research, “There is no evidence for a caries-therapeutic effect of xylitol,” which makes us wonder what side of the coin to believe. (12)

In my opinion, xylitol is relatively safe as a toothpaste or chewing gum sweetener, but it’s not recommended in large amounts for foods.

Xylitol vs. Stevia + Xylitol Alternatives

While the message is a little cloudy about the xylitol side effects, of the 345+ scientific papers referencing stevia, one message is clear: It is safe and effective. (13) As stated in the most recent critical evaluation, stevia “has a low glycemic index and, in the doses tested, is not cytotoxic nor has acute or chronic effect on blood sugar, which makes it a safe sweetener.” (14)

However, in spite of being a natural herb, not all stevia products on the shelves are created equal. In fact, in some of the more inferior brands, what they advertise as stevia isn’t even 100 percent stevia. It is cut with xylitol and disease-causing fillers like dextrose and sugar.

Most people do well with stevia, but listen to your body because stevia is an herb and everyone’s body may react differently to it. If you can’t get over its savory (almost tangy) flavor, however, some other natural sweeteners you may want to try are:

  1. Raw local honey (my personal favorite!)
  2. Dates
  3. Coconut nectar/sugar
  4. Grade B or C maple syrup


Xylitol alternatives - Dr. Axe


A good of thumb is that if it sounds too good to be true, then it probably is. If you want to satisfy your sweet tooth, include the herb stevia as a wonder alternative to sugar. It can easily be used in all of your deserts and drinks. It tastes great, has zero calories and is as natural as it gets.

Final Thoughts on Xylitol Side Effects

  • Xylitol is a sugar alcohol, which is a low-digestible carbohydrate that resists starches and includes fiber.
  • It has been reported that xylitol can raise blood glucose levels, which suggests that diabetics shouldn’t consume it.
  • Xylitol side effects also include constipation, gas, bloating, diarrhea, nausea, borborygmi, colic, increased bowel movements and weight gain.
  • Health care professionals do recommend xylitol for its oral health benefits, and research shows it does have the ability to prevent cavities.
  • In my opinion, xylitol is relatively safe as a toothpaste or chewing gum sweetener, but it’s not recommended in large amounts for foods.
  • Instead of xylitol, use natural sweeteners like stevia, raw honey, dates, coconut nectar, coconut sugar and maple syrup.

Read Next: Erythritol: The Good, the Bad & the Ugly with This Common Sweetener

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