The gastrointestinal and microbiome impact of a resistant starch blend from potato, banana, and apple fibers: A randomized clinical trial using smart caps.

The gastrointestinal (GI) impact of fibers including resistant starch (RS) consumption depends on various types and amounts of fibers, the initial microbiome states, and accurate intake measurements. A randomized clinical trial evaluated the GI impact of varying doses of a novel resistant starch blend (RSB) with smart cap monitoring. RSB contained at least 50% RS and was a proprietary mixture of a potato starch, green banana flour, and apple fiber powder (a source of apple pectin, not resistant starch). The study design randomized participants to one of four arms: 10 g/day of potato starch (0 RSB), 10 g/day of RSB, 10 to 20 to 20 g/day of RSB or 10 to 20 to 30 g/day RSB for two-week intervals over 6 weeks. Results confirmed that while resistant starch of approximately 5 g per day improves GI symptoms at 2, 4, and 6 weeks, it did not demonstrate a detectable effect on short chain fatty acids. Increasing doses of the blend (RSB) led to a decrease in the diarrhea score. Using an estimate of total consumption of RSB based on smart cap recordings of container openings and protocol-specified doses of RSB, a reduction in the sleep disturbance score was associated with higher RSB dose. The exploratory microbiome evaluation demonstrated that among the 16S rRNA gene sequences most associated with the consumption of the novel blend RSB, two belong to taxa of notable interest to human health: Faecalibacterium and Akkermansia.

Short-Term Tolerability, Safety, and Gut Microbial Composition Responses to a Multi-Strain Probiotic Supplement: An Open-Label Study in Healthy Adults.

BACKGROUND: Probiotics are among the most commonly used dietary supplements and evidence of their efficacy is increasing. Despite the long historical use of probiotics, some experts suggest that additional research is necessary to understand their potential risks. OBJECTIVES: Main aims of this study were to assess short-term tolerability and safety of a new, high colony-forming unit count, multi-strain probiotic supplement. Exploratory objectives included evaluating effects on gut microbial composition. METHODS: Ten healthy adults were enrolled in a single-arm, open-label study. Over a 10-day period, participants consumed a once daily probiotic capsule (2.1 x 1011 CFU) containing Lactobacillus acidophilus NCFM, Lactobacillus paracasei Lpc-37, Lactobacillus plantarum Lp-115, Lactobacillus rhamnosus GG, Lactobacillus rhamnosus HN001, Bifidobacterium lactis Bi-07, Bifidobacterium lactis Bl-04, and Bifidobacterium lactis HN019. The primary measure of tolerability pertained to whether or not participants completed the study. Secondary safety measures included clinical biomarkers from a routine metabolic panel and a complete blood count. Exploratory measures included stool microbiota counts. RESULTS: All participants completed the study and there were no serious adverse events. All documented adverse events were prompted by the investigators and the most commonly reported symptoms were gastrointestinal. There was a single instance of a biomarker abnormality in one individual. Overall, decreases in total bilirubin and aspartate aminotransferase, and increases in stool levels of Lactobacillus species, Faecalibacterium prausnitzii, and Akkermansia muciniphila (P < .05) were observed over the course of the study. CONCLUSIONS: The findings of this study suggest the multi-strain probiotic supplement was well-tolerated and most likely safe. Changes in liver function measures suggest the probiotics could potentially impact liver health. Stool microbiota changes suggest the probiotic could potentially impact gut health by affecting levels of intestinal microbiota that have been described as bioindicators of health and potential keystone species. However, additional research is necessary to follow up on the exploratory findings of this preliminary work.

Activation of bile acid signaling improves metabolic phenotypes in high-fat diet-induced obese mice.

The metabolic benefits induced by gastric bypass, currently the most effective treatment for morbid obesity, are associated with bile acid (BA) delivery to the distal intestine. However, mechanistic insights into BA signaling in the mediation of metabolic benefits remain an area of study. The bile diversion () mouse model, in which the gallbladder is anastomosed to the distal jejunum, was used to test the specific role of BA in the regulation of glucose and lipid homeostasis. Metabolic phenotype, including body weight and composition, glucose tolerance, energy expenditure, thermogenesis genes, total BA and BA composition in the circulation and portal vein, and gut microbiota were examined. BD improves the metabolic phenotype, which is in accord with increased circulating primary BAs and regulation of enterohormones. BD-induced hypertrophy of the proximal intestine in the absence of BA was reversed by BA oral gavage, but without influencing BD metabolic benefits. BD-enhanced energy expenditure was associated with elevated TGR5, D2, and thermogenic genes, including UCP1, PRDM16, PGC-1α, PGC-1ß, and PDGFRα in epididymal white adipose tissue (WAT) and inguinal WAT, but not in brown adipose tissue. BD resulted in an altered gut microbiota profile (i.e., Firmicutes bacteria were decreased, Bacteroidetes were increased, and Akkermansia was positively correlated with higher levels of circulating primary BAs). Our study demonstrates that enhancement of BA signaling regulates glucose and lipid homeostasis, promotes thermogenesis, and modulates the gut microbiota, which collectively resulted in an improved metabolic phenotype.