Limited research exists on
carbohydrate intake and oral microbiome diversity and composition assessed with next-generation sequencing. We aimed to better understand the association between habitual
carbohydrate intake and the oral microbiome, as the oral microbiome has been associated with caries,
periodontal disease, and systemic diseases. We investigated if total
carbohydrates,
starch,
monosaccharides,
disaccharides, fiber, or glycemic load (GL) were associated with the diversity and composition of oral bacteria in subgingival plaque samples of 1204 post-menopausal women.
Carbohydrate intake and GL were assessed from a food frequency questionnaire, and adjusted for energy intake. The V3-V4 region of the
16S rRNA gene from subgingival plaque samples were sequenced to identify the relative abundance of microbiome compositional data expressed as operational taxonomic units (OTUs). The abundance of OTUs were centered log(2)-ratio transformed to account for the compositional data structure. Associations between
carbohydrate/GL intake and microbiome alpha-diversity measures were examined using linear regression. PERMANOVA analyses were conducted to examine microbiome beta-diversity measures across quartiles of
carbohydrate/GL intake. Associations between intake of
carbohydrates and GL and the abundance of the 245 identified OTUs were examined by using linear regression. Total
carbohydrates, GL,
starch,
lactose, and
sucrose intake were inversely associated with alpha-diversity measures. Beta-diversity across quartiles of total
carbohydrates, fiber, GL,
sucrose, and
galactose, were all statistically significant (p for PERMANOVA p < 0.05). Positive associations were observed between total
carbohydrates, GL,
sucrose and Streptococcus mutans; GL and both Sphingomonas HOT 006 and Scardovia wiggsiae; and
sucrose and Streptococcus lactarius. A negative association was observed between
lactose and Aggregatibacter segnis, and between
sucrose and both TM7_[G-1] HOT 346 and Leptotrichia HOT 223. Intake of total
carbohydrate, GL, and
sucrose were inversely associated with subgingival bacteria alpha-diversity, the microbial beta-diversity varied by their intake, and they were associated with the relative abundance of specific OTUs. Higher intake of
sucrose, or high GL foods, may influence poor oral health outcomes (and perhaps systemic health outcomes) in older women via their influence on the oral microbiome.