Background
Despite many potential effects of the oral microbiome on oral and
systemic health, scant information is available regarding the associations
between diet and the oral microbiome.
Methods
Oral rinse DNA samples from 182 participants in a population-based
case–control study for colorectal cancer were used to amplify a
V3–V4 region of bacterial 16S rRNA gene. The amplicons were
sequenced using Illumina MiSeq paired end chemistry on 2 runs, yielding
approximately 33 million filtered reads that were assigned to bacterial
classes. Relative abundances of each class and family as well microbial
diversity/richness indices were correlated with selected dietary intakes
from a food frequency questionnaire.
Results
Saturated fatty acids (SFAs) and vitamin C intakes were consistently
correlated with alpha (within-subjects) diversity indexes in both richness
and diversity. SFA intake was positively correlated with relative abundance
of betaproteobacteria and fusobacteria. Vitamin C and other vitamins with
correlated intakes—for example, the B vitamins and vitamin
E—exhibited positive correlations with fusobacteria class, its
family Leptotrichiaceae and a clostridia family Lachnospiraceae. In
addition, glycemic load was positively correlated with Lactobacillaceae
abundance.
Conclusion
The observed associations in this study were modest. However, the
results suggest that the effects of diets are likely to be habitat specific,
and observations from the gut microbiome are not transferrable to the oral
microbiome. Further studies are warranted, incorporating a range of host
biomarkers, such as cytohistological, molecular, or biochemical
measurements, in order to address biological consequences of these dietary
intakes in human oral health.