Are weight and diet related to the gut microbiome in healthy college students living in the dorms?: a cross-sectional observational analysis

College weight gain and obesity are significant problems impacting our society, leading to a considerable number of comorbidities during and after college. Gut microbiota are increasingly recognized for their role in obesity and weight gain. Currently, research exploring the gut microbiome and its associations with dietary intake and body mass index (BMI) is limited among this population. Therefore, the purpose of this study was to assess associations between the gut microbiome, BMI, and dietary intake in a population of healthy college students living in two dorms at Arizona State University (n=90). Cross-sectional analyses were undertaken including 24-hour dietary recalls and anthropometrics (height, weight and BMI). High throughput Bacterial 16S rRNA gene sequencing of fecal samples was performed to quantify the gut microbiome and analyses were performed at phyla and family levels. Within this population, the mean BMI was 24.4 ± 5.3 kg/m2 and mean caloric intake was 1684 ± 947 kcals/day. Bacterial community analysis revealed that there were four predominant phyla and 12 predominant families accounting for 99.3% and 97.1% of overall microbial communities, respectively. Results of this study suggested that a significant association occurred between one principal component (impacted most by 22 microbial genera primarily within Firmicutes) and BMI (R2=0.053, p=0.0301). No significant correlations or group differences were observed when assessing the Firmicutes/Bacteroidetes ratio in relation to BMI or habitual dietary intake. These results provide a basis for gut microbiome research in college populations. Although, findings suggest that groups of microbial genera may be most influential in obesity, further longitudinal research is necessary to more accurately describe these associations over me. Findings from future research may be used to develop interventions to shift the gut microbiome to help moderate or prevent excess weight gain during this important life stage.