The gastrointestinal microbiota has an important role in human health, and there is increasing interest in utilizing dietary approaches to modulate the composition and metabolic function of the ...microbial communities that colonize the gastrointestinal tract to improve health, and prevent or treat disease. One dietary strategy for modulating the microbiota is consumption of dietary fiber and prebiotics that can be metabolized by microbes in the gastrointestinal tract. Human alimentary enzymes are not able to digest most complex carbohydrates and plant polysaccharides. Instead, these polysaccharides are metabolized by microbes which generate short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate. This article reviews the current knowledge of the impact of fiber and prebiotic consumption on the composition and metabolic function of the human gastrointestinal microbiota, including the effects of physiochemical properties of complex carbohydrates, adequate intake and treatment dosages, and the phenotypic responses related to the composition of the human microbiota.
Exercise is associated with altered gut microbial composition, but studies have not investigated whether the gut microbiota and associated metabolites are modulated by exercise training in humans. We ...explored the impact of 6 wk of endurance exercise on the composition, functional capacity, and metabolic output of the gut microbiota in lean and obese adults with multiple-day dietary controls before outcome variable collection.
Thirty-two lean (n = 18 9 female) and obese (n = 14 11 female), previously sedentary subjects participated in 6 wk of supervised, endurance-based exercise training (3 d·wk) that progressed from 30 to 60 min·d and from moderate (60% of HR reserve) to vigorous intensity (75% HR reserve). Subsequently, participants returned to a sedentary lifestyle activity for a 6-wk washout period. Fecal samples were collected before and after 6 wk of exercise, as well as after the sedentary washout period, with 3-d dietary controls in place before each collection.
β-diversity analysis revealed that exercise-induced alterations of the gut microbiota were dependent on obesity status. Exercise increased fecal concentrations of short-chain fatty acids in lean, but not obese, participants. Exercise-induced shifts in metabolic output of the microbiota paralleled changes in bacterial genes and taxa capable of short-chain fatty acid production. Lastly, exercise-induced changes in the microbiota were largely reversed once exercise training ceased.
These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent of diet and contingent on the sustainment of exercise.
In May 2019, the International Scientific Association for Probiotics and Prebiotics (ISAPP) convened a panel of nutritionists, physiologists and microbiologists to review the definition and scope of ...synbiotics. The panel updated the definition of a synbiotic to "a mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host". The panel concluded that defining synbiotics as simply a mixture of probiotics and prebiotics could suppress the innovation of synbiotics that are designed to function cooperatively. Requiring that each component must meet the evidence and dose requirements for probiotics and prebiotics individually could also present an obstacle. Rather, the panel clarified that a complementary synbiotic, which has not been designed so that its component parts function cooperatively, must be composed of a probiotic plus a prebiotic, whereas a synergistic synbiotic does not need to be so. A synergistic synbiotic is a synbiotic for which the substrate is designed to be selectively utilized by the co-administered microorganisms. This Consensus Statement further explores the levels of evidence (existing and required), safety, effects upon targets and implications for stakeholders of the synbiotic concept.
Objective: Pre-clinical evidence suggests that the gastrointestinal microbiota contributes to mood and behavior disorders. Among humans, diet quality and patterns, which also impact the ...gastrointestinal microbiota, have been linked to depression, anxiety, and stress. This review summarizes findings from clinical studies using dietary intervention to improve depression, anxiety, or stress and the role the gastrointestinal microbiota may have in these disorders.
Methods: A literature search was conducted using the keywords microbiome, microbiota, depression, anxiety, stress, diet, dietary pattern, diet quality, fiber, prebiotics, probiotics, and mood.
Results: Mood was improved by enhancing diet quality. Fructooligosaccharide and galactooligosaccharide improved anxiety and depression in participants consuming ≥ 5 g/day. Additionally, bifidobacteria were enriched in subjects consuming ≥ 5 g/day. Probiotic consumption improved psychological or biological measures of depression, anxiety, or stress in individuals predisposed to a mood disorder. Probiotics suppressed biological markers of stress in healthy individuals in a strain-dependent manner.
Discussion: High-quality diets, prebiotics, and probiotics may beneficially affect mood. Habitual diets rich in dietary fiber and omega-3-polyunsaturated fatty acids may be linked to reduced risk of developing symptoms of depression, anxiety, and stress; however, additional studies are necessary. Certain probiotics may enhance mood, but their influence on the gastrointestinal microbiota requires further investigation.
The Mediterranean diet pattern is increasingly associated with improved metabolic health. Two mechanisms by which consuming a Mediterranean diet pattern may contribute to improved metabolic health ...are modulation of the gastrointestinal (GI) microbiota and reduction of metabolic endotoxemia. Metabolic endotoxemia, defined as a 2- to 3-fold increase in circulating levels of bacterial endotoxin, has been proposed as a cause of inflammation during metabolic dysfunction. As the largest source of endotoxins in the human body, the GI microbiota represents a crucial area for research on strategies for reducing endotoxemia. Diets high in saturated fat and low in fiber contribute to metabolic endotoxemia through several mechanisms, including changes in the GI microbiome and bacterial fermentation end products, intestinal physiology and barrier function, and enterohepatic circulation of bile acids. Thus, the Mediterranean diet pattern, rich in unsaturated fats and fiber, may be one dietary strategy to reduce metabolic endotoxemia. Preclinical studies have demonstrated the differential effects of dietary saturated and unsaturated fats on the microbiota and metabolic health, but human studies are lacking. The role of dietary fiber and the GI microbiome in metabolic endotoxemia is underinvestigated. Clinical research on the effects of different types of dietary fat and fiber on the GI microbiota and GI and systemic inflammation is necessary to determine efficacious dietary strategies for reducing metabolic endotoxemia, inflammation, and subsequent metabolic disease.
Recent and ongoing developments in microbiome science are enabling new frontiers of research for probiotics and prebiotics. Novel types, mechanisms, and applications currently under study have the ...potential to change scientific understanding as well as nutritional and healthcare applications of these interventions. The expansion of related fields of microbiome-targeted interventions, and an evolving landscape for implementation across regulatory, policy, prescriber, and consumer spheres, portends an era of significant change. In this review we examine recent, emerging, and anticipated trends in probiotic and prebiotic science, and create a vision for broad areas of developing influence in the field.
An expanding range of candidate probiotic species and prebiotic substrates is emerging to address newly elucidated data-driven microbial niches and host targets.Overlapping with, and adjacent to, the probiotic and prebiotic fields, new variants of microbiome-modulating interventions are developing, including synbiotics, postbiotics, microbial consortia, live biotherapeutic products, and genetically modified organisms, with renewed interest in polyphenols, fibres, and fermented foods.Personalised nutrition and precision medicine are beginning to influence the application of probiotics and prebiotics, with growing interest in modulation of microbial signatures of health and disease.Demand for probiotics and prebiotics across divergent product formats is driving innovation in quality assurance techniques to measure dose, viability, and structural and functional integrity.
The gut microbiome in feast and famine Holscher, Hannah D
Nature reviews. Gastroenterology & hepatology,
11/2021, Letnik:
18, Številka:
11
Journal Article
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