Abstract
Objective: The role of human microbiota in celiac disease (CD) as well as the effect of the diet on the oral microbiota is still unclear. In this study, we measured variations of salivary microbiota and metabolome of Saharawi CD children and evaluated their potential associations with CD and gluten-free diet (GFD).
Methods: Fourteen Saharawi children, with biopsy-proved CD, under GFD treatment for at least two-years (T-CD) and following African-style dietary habits, were enrolled. Saharawi T-CD children were subjected to GFD under Italian-style dietary habits for 60 days. Salivary microbiota and metabolome under African and Italian-style GFD were analysed. A core salivary microbiota of Saharawi T-CD children before and after Italian-style GFD was identified and compared to Italian T-CD and healthy children (HC).
Results: We found significant (P < 0.05; FDR < 0.05) differences in the salivary microbiota and metabolome between African and Italian-style GFD. Compared to Italian T-CD children, sali-vary samples of Saharawi T-CD children under African GFD were characterized for the unusual presence of Clostridia and for a high abundance of some other Firmicutes, Actinobacteria and Tenericutes genera. Italian GFD positively affected the abundance of Granulicatella, Porphyromonas and Neisseria. On the contrary, Clostridium, Prevotella and Veillonella strongly decreased after 60 days of Italian GFD. The OTU co-occurrence/exclusion pattern was identified and strong correlations (P < 0.05; FDR < 0.05) were found between the core bacterial genera and volatile organic com-pounds (VOC). During Italian GFD, Saharawi T-CD children strongly increased the amount of VOC, especially, acetone and 2-butanone.
Conclusions: The insights gleaned should help to finding dietary implementation to improve health status of Saharawi T-CD chil-dren, and provide the first strong evidence for the effect of the diet on the human microbiota and metabolome.