University of Tartu, Lecturer in Oral and Dental Diseases, PhD
Every now and then, people ask me about the harmful properties of xylitol.
Xylitol is a natural substance which is much healthier than many other sugars. In moderate quantities, it is necessary for protecting teeth on a daily basis both in toothpastes as well as post-meal pastilles and chewing gums. As with every other sugar, excessive xylitol consumption also has some harmful effects.
Where does xylitol come from?
Xylitol is produced from plants containing xylan.
Xylitol use and research began already in the 1970s in Finland and the United States, thanks to which its effects are already quite extensively documented.
Effect on body weight
Although the energy value of xylitol is lower (almost by half, i.e. 2.4 kcal/g) than that of white table sugar, it still contains calories. When looking to lose weight, you should always consider your energy intake.
Suitability for diabetics
For diabetics, xylitol is a safer alternative than regular sugar, as it is absorbed and raises blood sugar levels considerably more slowly and less than the latter. Although xylitol has a low glycaemic index, it is still partially absorbed in the body, which must be taken into account if you are diabetic.
Side effects and allergy
In large quantities, sugar alcohols (sorbitol, mannitol, maltitol, lactitol, etc.) have a laxative effect in our intestines. As xylitol is broken down by the bacteria in our intestines, it releases an abundance of gases, leading to abdominal bloating and mild diarrhoea.
The safe amount of xylitol for avoiding side effects is individual. The maximum dose which mostly does not cause gastrointestinal discomfort is 0.3 grams of xylitol per kilogram of body weight. The average well-tolerated amount is 40 to 50 grams per day for adults and up to 20 grams for children. This is several times higher than the recommended daily amount for preventing dental caries, which is 6 to 10 grams.
Since xylitol is also produced when other sugars are broken down during digestion, allergic reactions are very rare. The main symptoms are itching, redness, swelling or hives. It is suspected that allergic reactions are not actually related to xylitol itself, but other substances used in the production of xylitol, such as nickel, which is a common allergen. Throughout the world, only a handful of cases of severe allergic reactions have ever been reported.
The only serious case in which xylitol (and many other sweeteners) should be avoided is if you suffer from irritable bowel syndrome or other conditions accompanied by diarrhoea.
To our pets and especially to dogs, xylitol is toxic and can cause a life-threatening condition in as little as 10 to 60 minutes, in which case quick veterinary intervention is crucial!