The Effect of Prolonged Low-calorie Sweetener Consumption in Overweight and Obese Young Adults

Consumption of low calorie sweeteners (LCS) is associated with development of metabolic diseases in observational studies. Findings primarily in rodent models demonstrate that LCS-induced alterations in the gut microbiome may contribute to the development of these metabolic abnormalities. This study investigates the effects of eight weeks of LCS exposure in young adult females with overweight and obesity (n=8) by comparing microflora in stool samples before and after ingestion of 12 oz. of diet soda containing sucralose and acesulfame-potassium three times daily for eight weeks. An additional stool sample was collected one week prior to beginning the intervention to measure normal microbiome variation. DNA was extracted using a PowerFecal DNA isolation kit and sequenced using shotgun metagenomic sequencing on an Illumina Nextseq 500 at the GW Genomics Core. Bioinformatics techniques were then applied to characterize microbiome diversity and compare the microflora composition of each individual one week prior to baseline, at baseline (pre-intervention), and post intervention. Cleaned reads were mapped to existing bacterial genomes using Pathoscope. Results were visualized and conceptualized in R using packages ggplot, phyloseq, and mvabund. Preliminary results indicate that there is varying microflora composition between individuals, much of which may be due to normal gut microbiome variation. A total of 1156 unique prokaryotic organisms were identified in this study. Greater than 50% of the mapped bacteria were from the genus Bacteroides. In particular, the genera Oscillospira, which is associated with greater diversity of gut microbiome, and Roseburia, which is associated with weight loss and reduced glucose intolerance in mice, were identified. Notably, greater consistency in microbiota composition was observed between visits than between different individuals, suggesting that any effects of LCS on the gut microbiota were less marked than differences in composition that already exist between individuals. More robust conclusions will be made following the completion of the analysi