Ingredient 101: Xylitol

Xylitol is a naturally occurring sugar alcohol found in certain fruits and vegetables like berries and birch trees. Unlike traditional sugars like sucrose (table sugar), xylitol doesn’t readily ferment in the mouth, meaning it doesn’t feed the bacteria that cause cavities [1].

The potential benefits of xylitol for oral health were first recognised in Finland in the 1970s. Researchers observed that children in areas with high xylitol consumption had significantly lower rates of cavities. This intriguing observation sparked further research into the unique properties of this sugar alcohol [2].

How does it work?

While it’s clear that xylitol promotes oral health, the exact mechanisms have been a subject of ongoing investigation. Several theories have been proposed:

Increased Salivation:

Xylitol’s sweetness is well known to stimulate saliva production, which helps wash away food particles, neutralise acids, and provide minerals for remineralisation [3]. However, increased saliva production has largely been dismissed as xylitol’s main mode of action in preventing cavities, as other sweeteners also increase saliva flow without the same cavity-preventing effects [4].

While not the primary mechanism, increased saliva flow is still beneficial, especially for individuals with dry mouth (xerostomia). Saliva plays a crucial role in oral health by protecting tissues, lubricating the mouth, and maintaining a balanced pH. Furthermore, xerostomia is said to further exacerbate demineralisation and put individuals at a greater risk of developing cavities [5].

Regulation of the Biofilm:

A more widely accepted theory suggests that xylitol disrupts the growth of cavity causing bacteria (in particular Streptococcus mutans). Xylitol is actively taken up by these bacteria, but they cannot efficiently convert it into energy. This creates an energy deficiency which hinders bacterial growth and acid production, both key factors in cavity formation [6]. Essentially, xylitol tricks the bacteria into consuming it thinking that it is sugar, but they gain no nutritional benefit and are unable to thrive.

Calcium Ion Carrier:

Emerging research suggests that xylitol may play a role in remineralisation, the process of repairing tooth enamel [7]. Xylitol might act as a calcium ion carrier, supplying the middle and deep layers of an early caries lesion with calcium ions from the remineralising solution, thereby enhancing remineralisation [8]. One might speculate that by potentially reaching deeper into the affected areas of the tooth, xylitol could work synergistically with other ingredients in toothpaste to contribute to enhanced enamel repair.

Xylitol in Toothpaste

Given its numerous oral health benefits, xylitol has become a popular ingredient in toothpastes. It is included in both the EvaGlo Adult mint and kids strawberry mint toothpaste.

Synergy with Other Ingredients:

It has been observed that toothpastes containing the foaming agent sodium lauryl sulphate (SLS) might hinder the action of xylitol [4]. EvaGlo toothpaste utilises a mild, coconut-derived foaming agent which is considered to be preferable to prevent any interference with xylitol’s mode of action.

Xylitol’s potential as a calcium ion carrier may synergistically enhance the effects of nano-hydroxyapatite (n-HA), another key ingredient in EvaGlo toothpaste. Nano-hydroxyapatite can become incorporated into the dental biofilm where it acts as a calcium reservoir, releasing calcium ions to aid in remineralisation during acid attacks [9]. By including xylitol with n-Ha in our formulation, EvaGlo toothpaste offers a comprehensive approach to oral care, supporting cavity prevention, enamel repair, and supporting a healthy oral microbiome.

Does xylitol impact your gut microbiome?

Xylitol has a reputation for inhibiting biofilms and the growth of cavity-causing bacteria in the oral cavity. This might lead to the assumption that it acts as an antimicrobial agent and may be harmful to your gut microbiome if it is ingested. In contrast, xylitol’s interaction with the gut microbiome is highly sophisticated, it has been shown to selectively promote beneficial bacteria while inhibiting potentially harmful species. So, if xylitol does not act like an antimicrobial, then what it is? The literature tells us that xylitol is considered to be a prebiotic [10].

When xylitol is ingested, about 50% of it is absorbed in the small intestine and the rest enters the colon where it is fermented by bacteria [10,11]. Previous research has shown that in the colon, xylitol increases the production of short-chain fatty acids (such as butyrate, propionate and acetate), which support overall health. Short-chain fatty acids are known to help regulate the absorption of water and minerals in the gut and lower the pH of the colon, creating a more favourable environment for beneficial bacteria [10,12]. Interestingly, this acidification in the colon also enhances the solubility and absorption of minerals like calcium. Although this is typically discussed in the context of bone strength, improved calcium absorption could also support the maintenance of healthy teeth [11].

Research shows that xylitol can have a beneficial impact on the gut microbiome, supporting our confidence that EvaGlo toothpaste is safe if swallowed—especially for young children who may unintentionally ingest their toothpaste. However, it’s important to note that xylitol, like other prebiotics, can have a mild laxative effect when consumed in large quantities. If xylitol is also being consumed through sweets, drinks, or other foods, the cumulative amount could lead to increased bowel movements in some individuals [11].