Brushing with toothpaste containing sodium dodecyl sulfate (SDS) may temporarily impair the oesophageal barrier and trigger local immune responses, according to a study published in the journal Allergy (Wright BL et al., 2026). Research on 10 healthy participants found that SDS, a common detergent, remains in saliva for over an hour post-brushing, leading to a significant drop in mucosal impedance—a key indicator of epithelial barrier health.
How SDS Affects Oesophageal Barrier Function
The study utilized continuous oesophageal mucosal impedance monitoring to track how the lining of the throat responds to toothpaste residue. Within 30 minutes of brushing with 2 grams of SDS-containing paste, researchers observed a statistically significant decrease in impedance (p<0.01). This decline suggests that the detergent temporarily disrupts the epithelial barrier, which serves as the body’s first line of defense against irritants.
Proteomic analysis provided further insight into these changes. Investigators identified a downregulation of the tight junction pathway—the cellular “glue” that maintains barrier integrity. Simultaneously, pathways related to the complement and coagulation cascades were upregulated in the proximal oesophagus, signaling that the body’s local immune system is actively responding to the detergent exposure.
Did you know? Laboratory studies in animal models have previously shown that this disruption can promote eosinophilic inflammation, a hallmark of eosinophilic oesophagitis (EoE).
Long-Term Implications for Eosinophilic Oesophagitis
Eosinophilic oesophagitis (EoE) is a chronic allergic condition characterized by epithelial barrier dysfunction. While the study by Wright et al. focused on healthy adults, the authors note that the findings support the hypothesis that environmental detergents could contribute to the mechanisms driving EoE. The fact that SDS was detectable in 80% of participants’ saliva one hour after brushing suggests that the oesophagus is exposed to these chemicals for longer periods than previously assumed.
Larger trials are now required to determine if the transient barrier impairment observed in this study leads to long-term pathology in individuals already susceptible to oesophageal inflammation.
Managing Daily Oral Hygiene
For those concerned about oesophageal health, the researchers emphasize that these findings warrant further investigation into common household products. While this study does not provide a definitive causal link between daily brushing and the development of EoE, it highlights the biological activity of common detergent ingredients.
Frequently Asked Questions
What is sodium dodecyl sulfate (SDS)?
SDS is a detergent and surfactant commonly used in toothpaste to create foam and help remove debris from teeth.
Can toothpaste cause eosinophilic oesophagitis?
The study by Wright et al. (2026) suggests that SDS can impair the oesophageal barrier, but it does not confirm that toothpaste causes EoE. Larger clinical studies are needed to determine if repeated exposure leads to the disease.
How long does toothpaste residue stay in the mouth?
In the study, SDS remained detectable in the saliva of 80% of participants for at least one hour after brushing.
What were the main indicators of barrier disruption?
Researchers measured a significant drop in oesophageal mucosal impedance and observed a downregulation of proteins responsible for maintaining tight junctions in the oesophageal lining.
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