Two ingredients in our formula have very different jobs. Algin feeds your oral microbiome. Stevia simply gives harmful bacteria nothing to work with. We think both matter, and we'd rather explain them accurately than blur them together.
Algin: an actual prebiotic
Algin, or sodium alginate, comes from brown seaweed, and it's the true prebiotic in our formula. A prebiotic doesn't just avoid feeding harmful bacteria. It actively selects for the growth of beneficial ones. Alginate oligosaccharides have been shown to promote beneficial species like Bifidobacterium, Faecalibacterium and Lactobacillus, while inhibiting pathogenic ones. Studied directly in oral biofilms, alginate has also been found to potentiate antibacterial activity against Streptococcus mutans and reduce the attachment of Porphyromonas gingivalis, the bacterium most associated with chronic gum disease. Most oral care brands that talk about the microbiome reach for chicory root or probiotics. We chose seaweed.
Stevia: not a prebiotic, but not a risk either
Stevia doesn't feed your oral microbiome the way algin does, and we're not going to pretend it does. What it does is something quieter and just as useful: it gives cavity causing bacteria nothing to ferment. Streptococcus mutans produces the acid that erodes enamel by metabolizing fermentable sugars. Steviol glycosides, the sweet compounds in stevia, aren't recognized as a food source by these bacteria, so no fermentation happens and no acid gets produced. A review in Molecules concluded stevia can be considered a non cariogenic sweetener on this basis, and more recent research has found stevioside actively suppresses S. mutans biofilm formation rather than simply passing through unused.
Why we use three sweeteners, not one
Xylitol and erythritol work through a related but distinct mechanism. Bacteria attempt to metabolize them, spend energy trying, and get nothing back, which inhibits their growth over time. Xylitol is particularly effective against Streptococcus mutans and S. sobrinus. Erythritol targets S. mutans and is especially effective at reducing total plaque weight. Used together with stevia, which isn't fermented at all, the formula covers a broader range of bacterial behaviour than any single sweetener could on its own, all while contributing zero free sugar and zero acid production.
This is the actual difference between "natural" and thoughtfully formulated. A lot of natural sweeteners still ferment, still lower oral pH, and still feed the exact bacteria you're trying to avoid. Ours were chosen because none of them do.
Bastét reading list: prebiotics and sweeteners that don't feed cavities
- An In Vitro Study of Alginate Oligomer Therapies on Oral Biofilms
- Is Stevia rebaudiana Bertoni a Non Cariogenic Sweetener? A Review
- Growth and Viability of Streptococcus mutans in Sucrose With Different Concentrations of Stevia rebaudiana Bertoni
- Inhibition of Streptococcus mutans Biofilm Formation and Virulence by Natural Extract Stevioside
- Exploration of Singular and Synergistic Effect of Xylitol and Erythritol on Causative Agents of Dental Caries
Shop French Mint Toothpaste · Read the science behind 10% nHA
Written by Alexandra Baker, co-founder of Bastét.
