Alterations in fecal microbiota composition by probiotic supplementation in healthy adults: a systematic review of randomized controlled trials

Abstract

BackgroundThe effects of probiotic supplementation on fecal microbiota composition in healthy adults have not been well established. We aimed to provide a systematic review of the potential evidence for an effect of probiotic supplementation on the composition of human fecal microbiota as assessed by high-throughput molecular approaches in randomized controlled trials (RCTs) of healthy adults.MethodsThe survey of peer-reviewed papers was performed on 17 August 2015 by a literature search through PubMed, SCOPUS, and ISI Web of Science. Additional papers were identified by checking references of relevant papers. Search terms included healthy adult, probiotic, bifidobacterium, lactobacillus, gut microbiota, fecal microbiota, intestinal microbiota, intervention, and (clinical) trial. RCTs of solely probiotic supplementation and placebo in healthy adults that examined alteration in composition of overall fecal microbiota structure assessed by shotgun metagenomic sequencing, 16S ribosomal RNA sequencing, or phylogenetic microarray methods were included. Independent collection and quality assessment of studies were performed by two authors using predefined criteria including methodological quality assessment of reports of the clinical trials based on revised tools from PRISMA/Cochrane and by the Jadad score.ResultsSeven RCTs investigating the effect of probiotic supplementation on fecal microbiota in healthy adults were identified and included in the present systematic review. The quality of the studies was assessed as medium to high. Still, no effects were observed on the fecal microbiota composition in terms of α-diversity, richness, or evenness in any of the included studies when compared to placebo. Only one study found that probiotic supplementation significantly modified the overall structure of the fecal bacterial community in terms of β-diversity when compared to placebo.ConclusionsThis systematic review of the pertinent literature demonstrates a lack of evidence for an impact of probiotics on fecal microbiota composition in healthy adults. Future studies would benefit from pre-specifying the primary outcome and transparently reporting the results including effect sizes, confidence intervals, and P values as well as providing a clear distinction of between-group and within-group comparisons.

Lost in translation? The potential psychobiotic Lactobacillus rhamnosus (JB-1) fails to modulate stress or cognitive performance in healthy male subjects

“…In addition, L. rhamnosus treatment modulates the immune system (Forsythe et al, 2012;Karimi et al, 2009;Kozakova et al, 2016;Ma et al, 2004), intestinal motility , gut barrier function (Patel et al, 2012;Wang et al, 2012) and enteric nervous system (Kamiya et al, 2006;Ma et al, 2009). Taken together, these preclinical studies identify L. rhamnosus as a candidate psychobiotic with the one of the most comprehensive behavioural, physiological and neurobiological profiles.…”

“…Moreover, antidepressants have a delayed onset of action (Taylor et al, 2006) and we acknowledge that more than four weeks of psychobiotic treatment may be required in future studies in populations with stress-related psychiatric disorders. A recent systematic review indicated that the impact of probiotic supplementation on gut microbiota structure, including an assessment across features such as α-diversity, richness and evenness, in healthy controls was minimal (Kristensen et al, 2016). However, it is important to consider that probiotic treatment may impact the function of colonizing microbes or promote homeostasis of the gut microbiota, rather than change its composition (Sanders, 2016).…”

Consumption of a Bifidobacterium bifidum Strain for 4 Weeks Modulates Dominant Intestinal Bacterial Taxa and Fecal Butyrate in Healthy Adults

“…Accordingly, the European Union considers the term probiotic a health claim per se ("reference to probiotic/prebiotic implies a health benefit" [2]). However, although numerous studies have demonstrated the efficacy of different probiotic preparations in a number of pathological conditions (3), the potential benefits associated with probiotic consumption by the general (healthy) population remain unclear (4). The lack of a clear cause-and-effect relationship between probiotic intake and health benefits for the general consumer is the most frequent reason stated by the European Food Safety Authority (EFSA) for the rejection of all health claims requested for probiotics.…”

Revisión Bibliográfica: El Microbioma Humano

“…En estudios clínicos, observacionales y epidemiológicos en niños, existe evidencias suficiente sobre la asociación entre la exposición a antibióticos y un incremento en el riesgo de enfermedades como la obesidad, diabetes tipo 1 y 2, síndrome de intestino irritable, enfermedad celíaca, alergias y asma [11]. Por otra parte la administración de probióticos en forma sistemática no cuenta con suficiente evidencia de un impacto significativo sobre el microbioma fecal de adultos sanos [12]. Obviamente, estas observaciones, refuerzan la necesidad imperiosa de un uso racional de los antibió-ticos en situaciones indicadas y a dosis correctas.…”