Director, Johns Hopkins Center for Neurogastroenterology Johns Hopkins University School of Medicine Baltimore, MD
Claire Shortt, PhD, BSc1, Niall M. McGovern, BSc, MEng2, Eoghan Lafferty, BSc, MEng1, Stephen A. Bromley, BSc3, Peter Falck4, Pankaj J. Pasricha, MD5; 1FoodMarble Digestive Health, Dublin, Dublin, Ireland; 2FoodMarble DIgestive Health, Dublin, Dublin, Ireland; 3Carbiotix, Lund, Skane Lan, Sweden; 4Carbiotix AB, Kävlinge, Skane Lan, Sweden; 5Johns Hopkins University School of Medicine, Baltimore, MD
Introduction: Changes in gut microbiome composition and the attendant health benefits associated with prebiotic intake, vary from person-to-person, implying the need for personalisation. As the primary metabolite of colonic fermentation that can be detected on exhaled breath, hydrogen could be used to indicate when a prebiotic is being metabolized by the host microbiota. Methods: Volunteers (n=20) were studied in a double-blind, crossover design (1-week baseline, 2-weeks 1st prebiotic, 2-week wash-out, 2-weeks 2nd prebiotic, 1-week washout) using two different prebiotic fibres, a galacto-oligosaccharide (GOS) and a wheat dextrin (WD). Breath hydrogen scores were recorded using a portable breath analyser, while 6 faecal samples per individual were acquired during the study (2 baseline samples and 4 intervention samples) (Fig 1). Bacterial DNA was extracted and submitted to 16S rRNA sequencing on an iSeq platform (Carbiotix) to characterise the gut microbiota. Results: Five faecal samples were excluded due to low quality DNA. A mean number of 388 breath hydrogen levels were recorded per individual (SD 59). A high degree of interpersonal variation was apparent in both breath hydrogen and microbiome composition. We noted a consistent trend for increased abundance of the genus Bifidobacterium on administration of GOS (group 1, 1% (range 0-2.1) - 3.6% (0.4-14.2), p=0.004; group 2, 2.4% (0.03-11.6) - 10.2% (0.04-22), p=0.04) and in one of two groups following WD (group 1, 0.09% (0-10)- 1.1% (0-19),p=0.04). On an individual level, we saw greater changes in breath hydrogen on administration of GOS, which was less apparent if WD was taken first in sequence. We used repeated-measures-correlation to correlate the relative abundance of bacterial genera with weekly breath hydrogen. Following correction for multiple comparisons, only Bifidobacterium was significantly positively correlated with weekly breath hydrogen (r = 0.35, adjusted p-value = 0.016) (Fig 2). Discussion: These results reflect the known Bifidogenic effects of these prebiotics. Interestingly, Bifidobacterium are unable to produce hydrogen, as they do not possess hydrogenases. However, a possible mechanism is that the fermentation of these prebiotics resulted in an initial increase in hydrogen and other important products, and via cross-feeding, the growth of Bifidobacterium was supported, to varying degrees in all individuals. Future studies are needed to understand the processes at play.
Overview of study. A baseline was established for each user (week one). A prebiotic fibre was taken for a two week period (week two and three), followed by a two week wash-out period (week four and five), before switching to the other prebiotic intervention (week six and seven). No prebiotic was taken during week eight.
Breath hydrogen simple moving average (SMA) and Bifidobacterium abundance levels for one of the study participants for the duration of the study period.
Disclosures: Claire Shortt: FoodMarble Digestive Health – Employee. Niall McGovern: FoodMarble Digestive Health – Employee. Eoghan Lafferty: FoodMarble Digestive Health – Employee. Stephen Bromley indicated no relevant financial relationships. Peter Falck: Carbiotix AB – Employee, Stockholder/Ownership Interest (excluding diversified mutual funds). Pankaj Pasricha: Food Marble – Consultant, Stockholder/Ownership Interest (excluding diversified mutual funds).