A systematic scoping review of study methodology for randomized controlled trials investigating probiotics in athletic and physically active populations

Background:The purported ergogenic and health effects of probiotics have been a topic of great intrigue among researchers,practitioners,and the lay public alike.There has also been an increased research focus within the realm of sports science and exercise medicine on the athletic gut microbiota.However,compared to other ergogenic aids and dietary supplements,probiotics present unique study challenges.The objectives of this systematic scoping review were to identify and characterize study methodologies of randomized controlled trials investigating supplementation with probiotics in athletes and physically active individuals.Methods:Four databases(MEDLINE,CINAHL,Cochrane CENTRAL,and Cochrane Database of Systematic Reviews)were searched for randomized controlled studies involving healthy athletes or physically active individuals.An intervention with probiotics and inclusion of a control and/or placebo group were essential.Only peer-reviewed articles in English were considered,and there were no date restrictions.Results were extracted and presented in tabular form to detail study protocols,characteristics,and outcomes.Bias in randomized controlled trials was determined with the RoB 2.0 tool.Results:A total of 45 studies were included in the review,with 35 using a parallel group design and 10 using a cross-over design.Approximately half the studies used a single probiotic and the other half a multi-strain preparation.The probiotic dose ranged from 2×10^(8)to 1×10^(11)colony forming units daily,and the length of intervention was between 7 and 150 days.Fewer than half the studies directly assessed gastrointestinal symptoms,gut permeability,or the gut microbiota.The sex ratio of participants was heavily weighted toward males,and only 3 studies exclusively investigated females.Low-level adverse events were reported in only 2 studies,although the methodology of reporting varied widely.The risk of bias was generally low,although details on randomization were lacking in some studies.Conclusion:There is a substantial body of research on the effects of prob iotic supplementation in healthy athletes and physically active individuals.Considerable heterogeneity in probiotic selection and dosage as well as outcome measures has made clinical and mechanistic interpretation challenging for both health care practitioners and researchers.Attention to issues of randomization of participants,treatments and interventions,selection of outcomes,demographics,and reporting of adverse events will facilitate more trustworthy interpretation of probiotic study results and inform evidence-based guidelines.

Efficacy of probiotics supplementation in amelioration of celiac disease symptoms and enhancement of immune system

Patients with celiac disease(CD)have a mucosal layer that is unable to regulate the gut microbiota,leaving the host vulnerable to dangerous infections and antigens.When compared to healthy people,this dysbiosis is marked by a decrease in intra-and intergeneric biodiversity,which demonstrates an imbalance between helpful bacteria and possibly harmful or proinflammatory species.The early gut microbiota is influenced by the genotype of newborns with the HLADQ2 haplotypes,and this may modify how gluten is handled in the intestinal lumen,polarize innate or adaptive immune responses,and result in glutensensitive enteropathy.The outcome of gluten digestion can vary depending on the composition of the intestinal gut bacteria and the partial conversion of gluten into peptides larger than ten amino acids in the small intestines,which can be immunogenic.In the small intestine,114 different bacterial strains belonging to 32 different species have 27 of them exhibiting peptidolytic activity.Thus,the individual risk of developing a gluten-related illness is further influenced by microbial composition and gluten degrading capacity.The conclusion that lactobacilli and Bifidobacterium spp.may be used as a probiotic supplement in CD patients is based on their shared possession of the most extensive peptidolytic and proteolytic activity thought to be engaged in the breakdown of gluten among all potential bacterial genera present in the gut microbiota.In children with CD autoimmunity,daily oral dose of Lactobacillus.plantarum HEAL9 and Lactobacillus.paracasei 8700:2 was found to modify the peripheral immune response.Bifidobacterium.breve strains have demonstrated a beneficial effect on reducing pro-inflammatory cytokine TNF-production in CD children on gluten-free diets.

Effects of Bifidobacterium supplementation on intestinal microbiota composition and the immune response in healthy infants

Background:Intestinal microbiotas are thought to be the most important source of maturational stimuli to the development of the immune system.However,few studies have focused on the development of T helper(Th)1 immune response and antibody response to vaccinations in healthy infants,especially in a large cohort.Through this randomized,double-blind control trial,we investigated the effects of Bifidobacterium longum BB536(BB536)supplementation on intestinal microbiota composition and the immune response in term infants.Methods:In total,300 healthy newborns were recruited,randomized and fed formula either supplemented with BB536 or with no supplementation.Stool samples were analyzed at months 2,4 and 11.The representative cytokine for Th1[interferon-γ(IFN-γ)]and Th2[interleukin-4(IL-4)]secretion cells were measured using enzyme-linked immunospot assay at 4 and 7 months of age.The antibody response to vaccines was measured at months 7 and 11.Results:A total of 264 infants completed the study.The amount of bifidobacteria and the bifidobacteria/Enterobacteriaceae ratio(B/E)were signifi cantly higher in the BB536 supplementation group at months 2 and 4.The number of IFN-γsecretion cells and the ratio of IFN-γ/IL-4 secretion cells were increased in the BB536 supplementation group at 7 months.Moreover,the higher value of B/E in the early stages seems to be related to the increased Th1 response.No difference was observed between groups in the antibody response after vaccination.Conclusions:BB536 has positive effects on establishing a healthy intestinal microbiota early in life,and it also plays an important role in improving the Th1 immune response.