Xylitol is a polyol mainly used as a sweetener (E967). It is a sweetener called mass or low-calorie, that is to say that it has the same sweetening power as sucrose while being less caloric.
It is naturally present in certain foods, but for the food industry, it is produced chemically. Indeed, the extraction of xylitol from fruits, vegetables and cereals (berries, mushrooms, oats, corn, birch …) which contain it is not possible for industrial purposes as their content in this substance is low. There are therefore several production methods:
- Enzymatic production using yeasts or bacteria
- Extraction of birch hemicellulose which is converted into xylitol in several stages
It has two peculiarities which make it a substance appreciated by industrialists: its sweetening power is the same as sucrose for half the calories (2.4 kcal against 4 kcal for sucrose) with a very low glycemic index (GI) ( 7) interesting for diabetics.
Focus on polyols
Polyols or sugar alcohols (mannitol, sorbitol, maltitol, erythritol, etc.) are naturally present in certain foods. They are also chemically produced by the food industry. Polyols are low calorie sweeteners with a low impact on blood sugar. They are also used as additives for many other functions (stabilizers, thickeners and flavor enhancer …).
Where is it found?
Xylitol is widely used in the Nordic countries as well as in Asia, slightly less in France. It is found, however, in a wide range of specialized food products (for diabetics). Thus, a product marked “without added sugars” may contain xylitol. It is also marketed for use in cooking in the form of powder or granules.
Cosmetics, medicines and oral health products (mouthwashes, toothpaste, lozenges) may also contain xylitol. But the most common source of xylitol is sugar-free chewing gum. In fact, xylitol has a negative heat of dissolution (absorption of heat) which gives it a refreshing effect, a property appreciated for making these products. In addition, the European Food Safety Authority (EFSA) authorizes two claims concerning chewing gum containing xylitol: “Sugar-free chewing gum helps reduce demineralization of teeth. Demineralization can increase the risk of tooth decay. “And” Sugar-free chewing gum helps neutralize acidic plaque. Acid plaque can increase the risk of tooth decay. ”
It is also found naturally in very small quantities in certain fruits such as berries.
How to use it ?
Xylitol is slowly, and only partially absorbed, in the intestine. Too much of it can cause fluid retention, which leads to diarrhea. It is therefore not recommended to consume more than 50 g of xylitol per day for adults and 20 g for children because of its laxative effect.
In cooking, it can be used to replace sugar in preparations, in an equal amount of the latter. When heated, the sweetening power of xylitol rises. However, it cannot be used in preparations that also require yeast, because the yeasts cannot ferment xylitol and therefore produce the carbon dioxide that causes the dough to swell.
What effects on health?
It is a priori favorable to oral health
The anti-decay effect of xylitol is due to the fact that it replaces fermentable sugars in a diet, it reduces oral acidity, increases the amount of saliva. But studies that attribute it to direct anti-caries effects are still insufficient.
Xylitol is said to act on oral health, in particular by reducing the amount of Streptococcus mutans in saliva and dental plaque. Indeed, this bacterium will not be able to use xylitol for energy purposes as it does with sugars such as glucose and sucrose, which ultimately prevents it from manufacturing the acid responsible for demineralization of teeth.
Xylitol also appears to fight other bacteria responsible for cariogenic lesions. In addition, this sweetener would not be harmful to beneficial bacteria in the oral flora.
It has a low impact on blood sugar
As we have seen, xylitol has a low glycemic index, that is to say that it does not raise blood sugar as quickly and as strongly as sugar does. In addition, as it is only partially absorbed by the intestine, it increases the gastric emptying of the food bolus which also has an impact on blood sugar. Xylitol therefore allows people with diabetes or prediabetics to keep the pleasure of consuming a sweet product without damaging their metabolic parameters. However, it thus contributes to perpetuating the addiction to the sweet taste, which can, for some people, be counterproductive, in a health approach.
It would have a possible anticancer effect
Xylitol has shown anticancer effects that are not yet fully explained. In a very recent study, researchers tried to understand this mechanism using the parasitic fungus Cordyceps militaris. Cordyceps is a powerful anti-cancer fungus thanks to its secondary metabolite, cordycepin. However, this fungus contains a significant amount of xylitol. The researchers hypothesized that xylitol could become a useful supplement to help fight various cancers. In mice, an injection of xylitol has shown an anti-tumor effect, triggering oxidative stress in cancer cells leading to their death (apoptosis). Other observations have made it possible for researchers to see that xylitol sensitizes cancer cells to chemotherapeutic treatments. Properties which therefore remain to be proven in humans.
What effects on the microbiota?
Sweeteners generally appear to have a negative impact on the diversity of the gut microbiota. What about xylitol which is, after all, already present naturally in certain foods? Well, we don’t know yet. What we do know is that xylitol is not digested by gut enzymes, so the remaining 50% of food xylitol enters the colon where it can serve as an energy source for gut bacteria in the form of short chain fatty acids. These properties of xylitol are very similar to those of a prebiotic.
However a significant consumption of xylitol leads to increased osmotic pressure which contributes to laxative effects resulting in flatulence (and perhaps an imbalance of the microbiota).
More research is needed to find out to what extent xylitol changes the microbiota. And it is complicated to study this type of interaction as the parameters involved are numerous (type of diet, initial clinical parameters, etc.).