A prospective randomized, double-blind, placebo-controlled, dose-response relationship study to investigate efficacy of fructo-oligosaccharides (FOS) on human gut microflora

Effects of fructan and gluten on gut microbiota in individuals with self-reported non-celiac gluten/wheat sensitivity-a randomised controlled crossover trial

BACKGROUND

Individuals with non-celiac gluten/wheat sensitivity (NCGWS) experience improvement in gastrointestinal symptoms following a gluten-free diet. Although previous results have indicated that fructo-oligosaccharides (FOS), a type of short-chain fructans, were more likely to induce symptoms than gluten in self-reported NCGWS patients, the underlying mechanisms are unresolved.

METHODS

Our main objective was therefore to investigate whether FOS-fructans and gluten affect the composition and diversity of the faecal microbiota (16S rRNA gene sequencing), faecal metabolites of microbial fermentation (short-chain fatty acids [SCFA]; gas chromatography with flame ionization detector), and a faecal biomarker of gut inflammation (neutrophil gelatinase-associated lipocalin, also known as lipocalin 2, NGAL/LCN2; ELISA). In the randomised double-blind placebo-controlled crossover study, 59 participants with self-reported NCGWS underwent three different 7-day diet challenges with gluten (5.7 g/day), FOS-fructans (2.1 g/day), and placebo separately (three periods, six challenge sequences).

RESULTS

The relative abundances of certain bacterial taxa were affected differently by the diet challenges. After the FOS-fructan challenge, Fusicatenibacter increased, while Eubacterium (E.) coprostanoligenes group, Anaerotruncus, and unknown Ruminococcaceae genera decreased. The gluten challenge was primarily characterized by increased abundance of Eubacterium xylanophilum group. However, no differences were found for bacterial diversity (α-diversity), overall bacterial community structure (β-diversity), faecal metabolites (SCFA), or NGAL/LCN2. Furthermore, gastrointestinal symptoms in response to FOS-fructans were generally not linked to substantial shifts in the gut bacterial community. However, the reduction in E. coprostanoligenes group following the FOS-fructan challenge was associated with increased gastrointestinal pain. Finally, correlation analysis revealed that changes in gastrointestinal symptoms following the FOS-fructan and gluten challenges were linked to varying bacterial abundances at baseline.

CONCLUSIONS

In conclusion, while FOS-fructans induced more gastrointestinal symptoms than gluten in the NCGWS patients, we did not find that substantial shifts in the composition nor function of the faecal microbiota could explain these differences in the current study. However, our results indicate that individual variations in baseline bacterial composition/function may influence the gastrointestinal symptom response to both FOS-fructans and gluten. Additionally, the change in E. coprostanoligenes group, which was associated with increased symptoms, implies that attention should be given to these bacteria in future trials investigating the impact of dietary treatments on gastrointestinal symptoms.

TRIAL REGISTRATION

Clinicaltrials.gov as NCT02464150.

Mechanisms and Intervention of Prebiotic Foods in Musculoskeletal Health

The review focuses primarily on collating and analyzing the mechanistic research data that discusses the function of prebiotics to halt the frailty of musculoskeletal system. Musculoskeletal diseases (MSDs) are frequently reported to co-occur within their own categories of conditions, such as osteoarthritis, rheumatoid arthritis, gouty arthritis, and psoriatic arthritis owing to their overlapping pathogenesis. Consequently, the same drugs are often used to manage the complications of most types. A few recent studies have addressed the therapeutic functions of gut microbes toward those commonly shared MSD pathway targets. Improving microbial diversity and enriching their population in the gut would promote the regeneration and recovery of the musculoskeletal system. Prebiotics are usually nondigestible substrates that are selectively used or digested by the gut microbes conferring health promotion. The microbial fermentation of prebiotics generates numerous host-beneficial therapeutic molecules. This study inspects the presumptive functions of plant-derived prebiotics for the growth and restoration of intestinal microbiota and the consequent improvement of skeletal health. The review also highlights the discrete functions of prebiotics against inflammation, autoimmunity, infection, physiologic overloading mechanism, and aging-associated loss of metabolism in MSD.

Factors influencing conjugated linoleic acid content of dairy products: challenges and strategies

Conjugated linoleic acid (CLA), a bioactive fatty acid that provides various physiological benefits, has gained increasing attention in the food industry, and various studies have focused on enhancing its content in dairy products. The factors influencing CLA content in dairy products vary significantly, including lactation stage, breed type, seasonality, feed, management methods of the animals, the manufacturing processes, storage, and ripening periods of the product. Additionally, the incorporation of CLA-producing probiotic bacteria, such as Lactobacillus, Lactococcus, Bifidobacterium, and Propionibacterium, is an emerging study in this field. Studies have revealed that factors affecting the CLA content in milk affect that in dairy products as well. Furthermore, the species and strains of CLA-producing bacteria, fermentation conditions, ripening period, and type of dairy product are also contributing factors. However, production of CLA-enhanced dairy products using CLA-producing bacteria while maintaining their optimal viability and maximizing exposure to free linoleic acid remains limited. The current review emphasized the factors affecting the CLA content and related mechanisms, challenges in the application of CLA-producing probiotic bacteria, and strategies to address these challenges and enhance CLA production in dairy products. Therefore, the development of functional dairy products with enhanced CLA levels is expected to be possible.

Modulation of human gut microbiota by linear and branched fructooligosaccharides in an in vitro colon model (TIM-2)

AIMS

This study aimed to compare the effects of linear and branched fructooligosaccharides (FOS) extracted from chicory and grass (Lolium perenne), respectively on human microbiota composition, diversity, and metabolism.

METHODS AND RESULTS

To test the effects of linear and branched FOS on human microbiota we used the artificial in vitro human colon model (TIM-2). Microbiota composition and diversity were assessed by V3-V4 16S rRNA metagenomic sequencing, followed by differential taxa abundance and alpha/beta diversity analyses. SCFA/BCFA production was evaluated by gas chromatography-mass spectrometry. As a result, branched FOS had the most beneficial effects on microbial diversity and metabolite production. Also, branched FOS significantly increased the abundance of commensal bacteria associated with maintaining healthy gut functions and controlling inflammation, such as Butyricicoccus, Erysipelotrichaceae, Phascolarctobacterium, and Sutterella. Linear FOS also significantly increased the abundance of some other commensal gut bacteria (Anaerobutyricum, Lachnospiraceae, Faecalibacterium), but there were no differences in diversity metrics compared to the control.

CONCLUSIONS

The study revealed that branched FOS had the most beneficial effects compared to the linear FOS in vitro, concerning microbiota modulation, and metabolite production, making this a good candidate for further studies in food biotechnology.

Microbial metagenomic shifts in children with acute lymphoblastic leukaemia during induction therapy and predictive biomarkers for infection

BACKGROUND

Emerging evidence has indicated a link between the gut microbiota and acute lymphoblastic leukaemia (ALL). However, the acute changes in gut microbiota during chemotherapy and the predictive value of baseline gut microbiota in infectious complication remain largely unknown.

METHODS

Faecal samples (n = 126) from children with ALL (n = 49) undergoing induction chemotherapy were collected at three timepoints, i.e., initiation of chemotherapy (baseline, T0), 7 days (T1) and 33 days (T2) after initiation of chemotherapy. Gut microbiome profile was performed via metagenomic shotgun sequencing. The bioBakery3 pipeline (Kneaddata, Metaphlan 3 and HUMAnN) was performed to assign taxonomy and functional annotations. Gut microbiome at T0 were used to predict infection during chemotherapy.

RESULTS

The microbial diversities and composition changed significantly during chemotherapy, with Escherichia coli, Klebsiella pneumoniae and Bifidobacterium longum being the most prominent species. The microbial metabolic pathways were also significantly altered during chemotherapy, including the pathway of pyruvate fermentation to acetate and lactate, and assimilatory sulfate reduction pathway. The receiver operating characteristic (ROC) models based on Bifidobacterium longum at T0 could predict infectious complications during the first month of chemotherapy with the area under the curve (AUC) of 0.720.

CONCLUSIONS

Our study provides new insights into the acute changes in microbial and functional characteristics in children with ALL during chemotherapy. The baseline gut microbiota could be potential biomarkers for infections during chemotherapy.

TRIAL REGISTRATION

The study was approved by the Ethics Committee of Zhujiang Hospital, Southern Medical University (2021-KY-171-01) and registered on http://www.chictr.org.cn (ChiCTR2200065406, Registration Date: November 4, 2022).

Intervention with fructooligosaccharides, Saccharomyces boulardii, and their combination in a colitis mouse model

Objective

To examine the effects of an intervention with fructooligosaccharides (FOS), Saccharomyces boulardii, and their combination in a mouse model of colitis and to explore the mechanisms underlying these effects.

Methods

The effects of FOS, S. boulardii, and their combination were evaluated in a DSS-induced mouse model of colitis. To this end, parameters such as body weight, the disease activity index (DAI), and colon length were examined in model mice. Subsequently, ELISA was employed to detect the serum levels of proinflammatory cytokines. Histopathological analysis was performed to estimate the progression of inflammation in the colon. Gas chromatography was used to determine the content of short-chain fatty acids (SCFAs) in the feces of model mice. Finally, 16S rRNA sequencing technology was used to analyze the gut microbiota composition.

Results

FOS was slight effective in treating colitis and colitis-induced intestinal dysbiosis in mice. Meanwhile, S. boulardii could significantly reduced the DAI, inhibited the production of IL-1β, and prevented colon shortening. Nevertheless, S. boulardii treatment alone failed to effectively regulate the gut microbiota. In contrast, the combined administration of FOS/S. boulardii resulted in better anti-inflammatory effects and enabled microbiota regulation. The FOS/S. boulardii combination (109 CFU/ml and 107 CFU/ml) significantly reduced the DAI, inhibited colitis, lowered IL-1β and TNF-α production, and significantly improved the levels of butyric acid and isobutyric acid. However, FOS/S. boulardii 109 CFU/ml exerted stronger anti-inflammatory effects, inhibited IL-6 production and attenuated colon shortening. Meanwhile, FOS/S. boulardii 107 CFU/ml improved microbial regulation and alleviated the colitis-induced decrease in microbial diversity. The combination of FOS and S. boulardii significantly increased the abundance of Parabacteroides and decreased the abundance of Escherichia-Shigella. Additionally, it promoted the production of acetic acid and propionic acid.

Conclusion

Compared with single administration, the combination can significantly increase the abundance of beneficial bacteria such as lactobacilli and Bifidobacteria and effectively regulate the gut microbiota composition. These results provide a scientific rationale for the prevention and treatment of colitis using a FOS/S. boulardii combination. They also offer a theoretical basis for the development of nutraceutical preparations containing FOS and S. boulardii.

Research of saccharides and related biocomplexes: A review with recent techniques and applications

Saccharides and biocompounds as saccharide (sugar) complexes have various roles and biological functions in living organisms due to modifications via nucleophilic substitution, polymerization, and complex formation reactions. Mostly, mono-, di-, oligo-, and polysaccharides are stabilized to inactive glycosides, which are formed in metabolic pathways. Natural saccharides are important in food and environmental monitoring. Glycosides with various functionalities are significant in clinical and medical research. Saccharides are often studied with the chromatographic methods of hydrophilic interaction liquid chromatography and anion exchange chromatograpy, but also with capillary electrophoresis and mass spectrometry with their on-line coupling systems. Sample preparation is important in the identification of saccharide compounds. The cases discussed here focus on bioscience, clinical, and food applications.

A review on the use of prebiotics in ulcerative colitis

The gut microbiome in the inflammatory bowel disease, ulcerative colitis (UC), is different to that of healthy controls. Patients with UC have relative reductions in abundance of Firmicutes and Bifidobacterium in the colon, and an increase in sulfate-reducing bacteria. Prebiotics are dietary substrates which are selectively metabolised by the human colonic microbiota to confer health benefits to the host. This review explores our current understanding of the potential benefits of prebiotics on various clinical, biochemical, and microbiological endpoints in UC, including new perspectives gained from recent studies in the field. This review looks to the future and highlights the need for appropriately designed trials to explore this potentially exciting new avenue for the treatment of UC.

Next generation probiotics: Engineering live biotherapeutics

The population dynamics of the human microbiome have been associated with inflammatory bowel disease, cancer, obesity, autoimmune diseases, and many other human disease states. An emerging paradigm in treatment is the administration of live engineered organisms, also called next-generation probiotics. However, the efficacy of these microbial therapies can be limited by the organism's overall performance in the harsh and nutrient-limited environment of the gut. In this review, we summarize the current state of the art use of bacterial and yeast strains as probiotics, highlight the recent development of genetic tools for engineering new therapeutic functions in these organisms, and report on the latest therapeutic applications of engineered probiotics, including recent clinical trials. We also discuss the supplementation of prebiotics as a method of manipulating the microbiome and improving the overall performance of engineered live biotherapeutics.

Dietary carbohydrates regulate intestinal colonization and dissemination of Klebsiella pneumoniae

Bacterial translocation from the gut microbiota is a source of sepsis in susceptible patients. Previous work suggests that overgrowth of gut pathobionts, including Klebsiella pneumoniae, increases the risk of disseminated infection. Our data from a human dietary intervention study found that, in the absence of fiber, K. pneumoniae bloomed during microbiota recovery from antibiotic treatment. We thus hypothesized that dietary nutrients directly support or suppress colonization of this gut pathobiont in the microbiota. Consistent with our study in humans, complex carbohydrates in dietary fiber suppressed the colonization of K. pneumoniae and allowed for recovery of competing commensals in mouse models. In contrast, through ex vivo and in vivo modeling, we identified simple carbohydrates as a limiting resource for K. pneumoniae in the gut. As proof of principle, supplementation with lactulose, a nonabsorbed simple carbohydrate and an FDA-approved therapy, increased colonization of K. pneumoniae. Disruption of the intestinal epithelium led to dissemination of K. pneumoniae into the bloodstream and liver, which was prevented by dietary fiber. Our results show that dietary simple and complex carbohydrates were critical not only in the regulation of pathobiont colonization but also disseminated infection, suggesting that targeted dietary interventions may offer a preventative strategy in high-risk patients.

Effect of gut microbiome modulation on muscle function and cognition: the PROMOTe randomised controlled trial

Studies suggest that inducing gut microbiota changes may alter both muscle physiology and cognitive behaviour. Gut microbiota may play a role in both anabolic resistance of older muscle, and cognition. In this placebo controlled double blinded randomised controlled trial of 36 twin pairs (72 individuals), aged ≥60, each twin pair are block randomised to receive either placebo or prebiotic daily for 12 weeks. Resistance exercise and branched chain amino acid (BCAA) supplementation is prescribed to all participants. Outcomes are physical function and cognition. The trial is carried out remotely using video visits, online questionnaires and cognitive testing, and posting of equipment and biological samples. The prebiotic supplement is well tolerated and results in a changed gut microbiome [e.g., increased relative Bifidobacterium abundance]. There is no significant difference between prebiotic and placebo for the primary outcome of chair rise time (β = 0.579; 95% CI -1.080-2.239 p = 0.494). The prebiotic improves cognition (factor score versus placebo (β = -0.482; 95% CI,-0.813, -0.141; p = 0.014)). Our results demonstrate that cheap and readily available gut microbiome interventions may improve cognition in our ageing population. We illustrate the feasibility of remotely delivered trials for older people, which could reduce under-representation of older people in clinical trials. ClinicalTrials.gov registration: NCT04309292.

The effects of inulin-type fructans on cardiovascular disease risk factors: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Inulin-type fructans (ITF) are the leading prebiotics in the market. Available evidence provides conflicting results regarding the beneficial effects of ITF on cardiovascular disease risk factors.

OBJECTIVES

This study aimed to evaluate the effects of ITF supplementation on cardiovascular disease risk factors in adults.

METHODS

We searched MEDLINE, EMBASE, Emcare, AMED, CINAHL, and the Cochrane Library databases from inception through May 15, 2022. Eligible randomized controlled trials (RCTs) administered ITF or placebo (for example, control, foods, diets) to adults for ≥2 weeks and reported one or more of the following: low, very-low, or high-density lipoprotein cholesterol (LDL-C, VLDL-C, HDL-C); total cholesterol; apolipoprotein A1 or B; triglycerides; fasting blood glucose; body mass index; body weight; waist circumference; waist-to-hip ratio; systolic or diastolic blood pressure; or hemoglobin A1c. Two reviewers independently and in duplicate screened studies, extracted data, and assessed risk of bias. We pooled data using random-effects model, and assessed the certainty of evidence (CoE) using the Grading of Recommendations, Assessment, Development and Evaluation approach.

RESULTS

We identified 1767 studies and included 55 RCTs with 2518 participants in meta-analyses. The pooled estimate showed that ITF supplementation reduced LDL-C [mean difference (MD) -0.14 mmol/L, 95% confidence interval (95% CI: -0.24, -0.05), 38 RCTs, 1879 participants, very low CoE], triglycerides (MD -0.06 mmol/L, 95% CI: -0.12, -0.01, 40 RCTs, 1732 participants, low CoE), and body weight (MD -0.97 kg, 95% CI: -1.28, -0.66, 36 RCTs, 1672 participants, low CoE) but little to no significant effect on other cardiovascular disease risk factors. The effects were larger when study duration was ≥6 weeks and in pre-obese and obese participants.

CONCLUSION

ITF may reduce low-density lipoprotein, triglycerides, and body weight. However, due to low to very low CoE, further well-designed and executed trials are needed to confirm these effects.

PROSPERO REGISTRATION NUMBER

CRD42019136745.

In Vitro Assessment of Postbiotic and Probiotic Commercial Dietary Supplements Recommended for Counteracting Intestinal Dysbiosis in Dogs

Many environmental aspects influence the preservation of a beneficial microbiome in dogs, and gut dysbiosis occurs when imbalances in the intestinal ecosystem cause functional changes in the microbial populations. The authors evaluated the effects of two specific commercial dietary supplements: a combination of a postbiotic and prebiotics (Microbiotal cane®) and a probiotic product (NBF 1®) recommended for counteracting intestinal dysbiosis in dogs, on the gut canine microbiota composition and its metabolic activities (production of short-chain fatty acids). The investigation was performed using an in vitro fermentation system inoculated with dog fecal samples. Microbiotal cane® promoted a more immediate increase in Lactobacillus spp. after the first 6 h of fermentation, whereas NBF 1® promoted the increase at the end of the process only. The two supplements supported an increase in the Bifidobacterium spp. counts only after 24 h. The in vitro abilities of Microbiotal cane® and NBF 1® to increase selectively beneficial bacterial groups producing acetic, propionic, and butyric acids suggest a possible positive effect on the canine gut microbiota, even if further in vivo studies are needed to confirm the beneficial effects on the intestinal health.

Tunable control of B. infantis abundance and gut metabolites by co-administration of human milk oligosaccharides

Precision engineering of the gut microbiome holds promise as an effective therapeutic approach for diseases associated with a disruption in this microbial community. Engrafting a live biotherapeutic product (LBP) in a predictable, controllable manner is key to the consistent success of this approach and has remained a challenge for most LBPs under development. We recently demonstrated high-level engraftment of Bifidobacterium longum subsp. infantis (B. infantis) in adults when co-dosed with a specific prebiotic, human milk oligosaccharides (HMO). Here, we present a cellular kinetic-pharmacodynamic approach, analogous to pharmacokinetic-pharmacodynamic-based analyses of small molecule- and biologic-based drugs, to establish how HMO controls expansion, abundance, and metabolic output of B. infantis in a human microbiota-based model in gnotobiotic mice. Our data demonstrate that the HMO dose controls steady-state abundance of B. infantis in the microbiome, and that B. infantis together with HMO impacts gut metabolite levels in a targeted, HMO-dependent manner. We also found that HMO creates a privileged niche for B. infantis expansion across a 5-log range of bacterial inocula. These results demonstrate remarkable control of both B. infantis levels and the microbiome community metabolic outputs using this synbiotic approach, and pave the way for precision engineering of desirable microbes and metabolites to treat a range of diseases.

Tryptophan Metabolism and Gut Microbiota: A Novel Regulatory Axis Integrating the Microbiome, Immunity, and Cancer

Tryptophan metabolism and gut microbiota form an integrated regulatory axis that impacts immunity, metabolism, and cancer. This review consolidated current knowledge on the bidirectional interactions between microbial tryptophan processing and the host. We focused on how the gut microbiome controls tryptophan breakdown via the indole, kynurenine, and serotonin pathways. Dysbiosis of the gut microbiota induces disruptions in tryptophan catabolism which contribute to disorders like inflammatory conditions, neuropsychiatric diseases, metabolic syndromes, and cancer. These disruptions affect immune homeostasis, neurotransmission, and gut-brain communication. Elucidating the mechanisms of microbial tryptophan modulation could enable novel therapeutic approaches like psychobiotics and microbiome-targeted dietary interventions. Overall, further research on the microbiota-tryptophan axis has the potential to revolutionize personalized diagnostics and treatments for improving human health.

Tuning Expectations to Reality: Don't Expect Increased Gut Microbiota Diversity with Dietary Fiber

Dietary approaches, particularly those including fiber supplementation, can be used to promote health benefits by shaping gut microbial communities. Whereas community diversity measures, such as richness and evenness, are often used in microbial ecology to make sense of these complex and vast microbial ecosystems, it is less clear how these concepts apply when dietary fiber supplementation is given. In this perspective, we summarize and demonstrate how factors including experimental approach, number of bacteria sharing a dietary fiber, and initial relative abundances of bacteria that use a fiber can significantly affect diversity outcomes in fiber fermentation studies. We also show that a reduction in alpha diversity is possible, and perhaps expected, for most approaches that use fermentable fibers to beneficially shape the gut microbial community while still achieving health-related improvements.

Synbiotic Sapota-do-Solimões (Quararibea cordata Vischer) Juice Improves Gut Microbiota and Short-Chain Fatty Acid Production in an In Vitro Model

Sapota-do-Solimões (Quararibea cordata Vischer) is Amazon South América fruit found in Brazil, Colombia, Ecuador, and Peru. The orange-yellow fruit is usually eaten out of hand or as juice. Despite being a source of carotenoids and dietary fibers (pectin) that can reach the colon and act as an energy source for intestinal microbiota, the fruit is rarely known outside of South America. The symbiotic juice was prepared by fermenting the fruit juice with Lacticaseibacillus casei B-442 and adding prebiotic fructooligosaccharides (FOS, 7% w/v). This study evaluated the functional juice immediately after L. casei fermentation (SSJ0) and after 30 days of cold storage (SSJ30) regarding its effect on human colonic microbiota composition after in vitro fermentation. Fecal samples were collected from two healthy female volunteers, and the 16s rRNA gene sequencing analyzed the fecal microbiota composition. In vitro, colonic fermentation was performed using a batch bioreactor to simulate gastrointestinal conditions. The L. casei viability did not change significantly after 30 days of the synbiotic juice cold storage (4 °C). After the colonic fermentation, the relative abundance of Firmicutes decreased while Proteobacteria and Actinobacteria increased. Regarding short-chain fatty acid (SCFA) production by fecal colonic microbiota, the butyric acid was higher after sample SSJ0 fecal fermentation. In contrast, propionic, isobutyric, and acetic acids were higher after SSJ30 sample fecal fermentation. This study contributes to understanding the interactions between specific foods and the gut microbiota, which can affect human health and well-being.

Regulation of dietary fiber on intestinal microorganisms and its effects on animal health

The animal gut harbors diverse microbes that play an essential role in the well-being of their host. Specific diets, such as those rich in dietary fiber, are vital in disease prevention and treatment because they affect intestinal flora and have a positive impact on the metabolism, immunity, and intestinal function of the host. Dietary fiber can provide energy to colonic epithelial cells, regulate the structure and metabolism of intestinal flora, promote the production of intestinal mucosa, stimulate intestinal motility, improve glycemic and lipid responses, and regulate the digestion and absorption of nutrients, which is mainly attributed to short-chain fatty acids (SCFA), which is the metabolite of dietary fiber. By binding with G protein-coupled receptors (including GPR41, GPR43 and GPR109A) and inhibiting the activity of histone deacetylases, SCFA regulate appetite and glucolipid metabolism, promote the function of the intestinal barrier, alleviate oxidative stress, suppress inflammation, and maintain immune system homeostasis. This paper reviews the physicochemical properties of dietary fiber, the interaction between dietary fiber and intestinal microorganisms, the role of dietary fiber in maintaining intestinal health, and the function of SCFA, the metabolite of dietary fiber, in inhibiting inflammation. Furthermore, we consider the effects of dietary fiber on the intestinal health of pigs, the reproduction and lactation performance of sows, and the growth performance and meat quality of pigs.

Shotgun Metagenomic Sequencing Revealed the Prebiotic Potential of a Fruit Juice Drink with Fermentable Fibres in Healthy Humans

Fibre-based dietary interventions are at the forefront of gut microbiome modulation research, with a wealth of 16S rRNA information to demonstrate the prebiotic effects of isolated fibres. However, there is a distinct lack of data relating to the effect of a combination of soluble and insoluble fibres in a convenient-to-consume fruit juice food matrix on gut microbiota structure, diversity, and function. Here, we aimed to determine the impact of the MOJU Prebiotic Shot, an apple, lemon, ginger, and raspberry fruit juice drink blend containing chicory inulin, baobab, golden kiwi, and green banana powders, on gut microbiota structure and function. Healthy adults (n = 20) were included in a randomised, double-blind, placebo-controlled, cross-over study, receiving 60 mL MOJU Prebiotic Shot or placebo (without the fibre mix) for 3 weeks with a 3-week washout period between interventions. Shotgun metagenomics revealed significant between-group differences in alpha and beta diversity. In addition, the relative abundance of the phyla Actinobacteria and Desulfobacteria was significantly increased as a result of the prebiotic intervention. Nine species were observed to be differentially abundant (uncorrected p-value of <0.05) as a result of the prebiotic treatment. Of these, Bifidobacterium adolescentis and CAG-81 sp900066785 (Lachnospiraceae) were present at increased abundance relative to baseline. Additionally, KEGG analysis showed an increased abundance in pathways associated with arginine biosynthesis and phenylacetate degradation during the prebiotic treatment. Our results show the effects of the daily consumption of 60 mL MOJU Prebiotic Shot for 3 weeks and provide insight into the functional potential of B. adolescentis.

Functional β-mannooligosaccharides: Sources, enzymatic production and application as prebiotics

One of the emerging non-digestible oligosaccharide prebiotics is β-mannooligosaccharides (β-MOS). β-MOS are β-mannan derived oligosaccharides, they are selectively fermented by gut microbiota, promoting the growth of beneficial microorganisms (probiotics), whereas the growth of enteric pathogens remains unaffected or gets inhibited in their presence, along with production of metabolites such as short-chain fatty acids. β-MOS also exhibit several other bioactive properties and health-promoting effects. Production of β-MOS using the enzymes such as β-mannanases is the most effective and eco-friendly approach. For the application of β-MOS on a large scale, their production needs to be standardized using low-cost substrates, efficient enzymes and optimization of the production conditions. Moreover, for their application, detailed in-vivo and clinical studies are required. For this, a thorough information of various studies in this regard is needed. The current review provides a comprehensive account of the enzymatic production of β-MOS along with an evaluation of their prebiotic and other bioactive properties. Their characterization, structural-functional relationship and in-vivo studies have also been summarized. Research gaps and future prospects have also been discussed, which will help in conducting further research for the commercialization of β-MOS as prebiotics, functional food ingredients and therapeutic agents.

Dietary fibre definition revisited - The case of low molecular weight carbohydrates

Low molecular weight (LMW) non-digestible carbohydrates (namely, oligosaccharides and inulin) are accepted as dietary fibre in many countries worldwide. The inclusion of oligosaccharides as dietary fibre was made optional within the Codex Alimentarius definition in 2009, which has caused great controversy. Inulin is accepted as dietary fibre by default, due to being a non-digestible carbohydrate polymer. Oligosaccharides and inulin occur naturally in numerous foods and are frequently incorporated into commonly consumed food products for a variety of purposes, such as to increase dietary fibre content. LMW non-digestible carbohydrates, due to their rapid fermentation in the proximal colon, may cause deleterious effects in individuals with functional bowel disorders (FBDs) and, as such, are excluded on the low FODMAP (fermentable oligosaccharides, disaccharides, and polyols) diet and similar protocols. Their addition to food products as dietary fibre allows the use of associated nutrition/health claims, causing a paradox for those with FBDs, which is further complicated by lack of clarity on food labelling. Therefore, this review aimed to discuss whether the inclusion of LMW non-digestible carbohydrates within the Codex definition of dietary fibre is warranted. This review provides justification for the exclusion of oligosaccharides and inulin from the Codex definition of dietary fibre. LMW non-digestible carbohydrates could, instead, be placed in their own category as prebiotics, recognised for their specific functional properties, or considered food additives, whereby they are not promoted for being beneficial for health. This would preserve the concept of dietary fibre being a universally beneficial dietary component for all individuals.

Supplementation with inulin-type fructans affects gut microbiota and attenuates some of the cardiometabolic benefits of a plant-based diet in individuals with overweight or obesity

Background

The gut microbiota has emerged as a potential therapeutic target to improve the management of obesity and its comorbidities.

Objective

We investigated the impact of a high fiber (∼38 g/d) plant-based diet, consumed ad libitum, with or without added inulin-type fructans (ITF), on the gut microbiota composition and cardiometabolic outcomes in subjects with obesity. We also tested if baseline Prevotella/Bacteroides (P/B) ratio predicts weight loss outcomes.

Methods

This is a secondary exploratory analysis from the PREVENTOMICS study, in which 100 subjects (82 completers) aged 18-65 years with body mass index 27-40 kg/m2 were randomized to 10 weeks of double-blinded treatment with a personalized or a generic plant-based diet. Changes from baseline to end-of-trial in gut microbiota composition (16S rRNA gene amplicon sequencing), body composition, cardiometabolic health and inflammatory markers were evaluated in the whole cohort (n = 82), and also compared in the subgroup of subjects who were supplemented with an additional 20 g/d ITF-prebiotics (n = 21) or their controls (n = 22).

Results

In response to the plant-based diet, all subjects lost weight (-3.2 [95% CI -3.9, -2.5] kg) and experienced significant improvements in body composition and cardiometabolic health indices. Addition of ITF to the plant-based diet reduced microbial diversity (Shannon index) and selectively increased Bifidobacterium and Faecalibacterium (q < 0.05). The change in the latter was significantly associated with higher values of insulin and HOMA-IR and lower HDL cholesterol. In addition, the LDL:HDL ratio and the concentrations of IL-10, MCP-1 and TNFα were significantly elevated in the ITF-subgroup. There was no relationship between baseline P/B ratio and changes in body weight (r = -0.07, p = 0.53).

Conclusion

A plant-based diet consumed ad libitum modestly decreases body weight and has multiple health benefits in individuals with obesity. Addition of ITF-prebiotics on top this naturally fiber-rich background selectively changes gut microbiota composition and attenuates some of the realized cardiometabolic benefits.

Clinical trial registration

[https://clinicaltrials.gov/ct2/show/NCT04590989], identifier [NCT04590989].

Prebiotic Consumption Alters Microbiota but Not Biological Markers of Stress and Inflammation or Mental Health Symptoms in Healthy Adults: A Randomized, Controlled, Crossover Trial

BACKGROUND

Chronic stress contributes to systemic inflammation and diminished mental health. Although animal work suggests strong links with the microbiota-gut-brain axis, clinical trials investigating the effectiveness of prebiotics in improving mental health and reducing inflammation are lacking.

OBJECTIVES

We aimed to determine fructooligosaccharide (FOS) and galactooligosaccharide (GOS) effects on biological markers of stress and inflammation and mental health symptoms in adults. Secondary outcomes included fecal microbiota and metabolites, digestive function, emotion, and sleep.

METHODS

Twenty-four healthy adults (25-45 y; 14 females, 10 males; BMI, 29.3 ± 1.8 kg/m²) from central Illinois participated in a 2-period, randomized, controlled, single-blinded crossover trial. Interventions included the prebiotic (PRE) treatment (237 mL/d Lactaid low-fat 1% milk, 5 g/d FOS, 5 g/d GOS) and control (CON) (237 mL/d Lactaid), which were consumed in counterbalanced order for 4 wk each, separated by ≥4-wk washout. Inflammatory markers were measured in blood plasma (>10-h fast) and cortisol in urine. The Depression Anxiety Stress Scales-42 assessed mental health symptoms. Fecal samples were collected for 16S rRNA gene (V4 region) sequencing and analysis. Emotion was measured by rating images from a computer task. Sleep was assessed using 7-d records and accelerometers. Change scores were analyzed using linear mixed models with treatment and baseline covariate as fixed effects and participant ID as the random effect.

RESULTS

There were no differences in change scores between PRE and CON treatments on biological markers of stress and inflammation or mental health. PRE increased change in percent sequences (q = 0.01) of Actinobacteriota (CON: 0.46 ± 0.70%; PRE: 5.40 ± 1.67%) and Bifidobacterium (CON: -1.72 ± 0.43%; PRE: 4.92 ± 1.53%). There were also no differences in change scores between treatments for microbial metabolites, digestive function, emotion, or sleep quality.

CONCLUSIONS

FOS+GOS did not affect biological markers of stress and inflammation or mental health symptoms in healthy adults; however, it increased Bifidobacterium.

CLINICAL TRIAL REGISTRY

NCT04551937, www.

CLINICALTRIALS

gov.

Bioaccessibility and Bioavailability of Diet Polyphenols and Their Modulation of Gut Microbiota

It is generally accepted that diet-derived polyphenols are bioactive compounds with several potentially beneficial effects on human health. In general, polyphenols have several chemical structures, and the most representative are flavonoids, phenolic acids, and stilbenes. It should be noted that the beneficial effects of polyphenols are closely related to their bioavailability and bioaccessibility, as many of them are rapidly metabolized after administration. Polyphenols-with a protective effect on the gastrointestinal tract-promote the maintenance of the eubiosis of the intestinal microbiota with protective effects against gastric and colon cancers. Thus, the benefits obtained from dietary supplementation of polyphenols would seem to be mediated by the gut microbiota. Taken at certain concentrations, polyphenols have been shown to positively modulate the bacterial component, increasing Lactiplantibacillus spp. and Bifidobacterium spp. involved in the protection of the intestinal barrier and decreasing Clostridium and Fusobacterium, which are negatively associated with human well-being. Based on the diet-microbiota-health axis, this review aims to describe the latest knowledge on the action of dietary polyphenols on human health through the activity of the gut microbiota and discusses micro-encapsulation of polyphenols as a strategy to improve the microbiota.

An Overview of Inter-Tissue and Inter-Kingdom Communication Mediated by Extracellular Vesicles in the Regulation of Mammalian Metabolism

Obesity and type 2 diabetes are associated with defects of insulin action in different tissues or alterations in β-cell secretory capacity that may be triggered by environmental challenges, inadequate lifestyle choices, or an underlying genetic predisposition. In addition, recent data shows that obesity may also be caused by perturbations of the gut microbiota, which then affect metabolic function and energy homeostasis in the host. Maintenance of metabolic homeostasis in complex organisms such as mammals requires organismal-level communication, including between the different organs and the gut microbiota. Extracellular vesicles (EVs) have been identified in all domains of life and have emerged as crucial players in inter-organ and inter-kingdom crosstalk. Interestingly, EVs found in edible vegetables or in milk have been shown to influence gut microbiota or tissue function in mammals. Moreover, there is a multidirectional crosstalk mediated by EVs derived from gut microbiota and body organs that has implications for host health. Untangling this complex signaling network may help implement novel therapies for the treatment of metabolic disease.

Butyrate producers, "The Sentinel of Gut": Their intestinal significance with and beyond butyrate, and prospective use as microbial therapeutics

Gut-microbial butyrate is a short-chain fatty acid (SCFA) of significant physiological importance than the other major SCFAs (acetate and propionate). Most butyrate producers belong to the Clostridium cluster of the phylum Firmicutes, such as Faecalibacterium, Roseburia, Eubacterium, Anaerostipes, Coprococcus, Subdoligranulum, and Anaerobutyricum. They metabolize carbohydrates via the butyryl-CoA: acetate CoA-transferase pathway and butyrate kinase terminal enzymes to produce most of butyrate. Although, in minor fractions, amino acids can also be utilized to generate butyrate via glutamate and lysine pathways. Butyrogenic microbes play a vital role in various gut-associated metabolisms. Butyrate is used by colonocytes to generate energy, stabilizes hypoxia-inducible factor to maintain the anaerobic environment in the gut, maintains gut barrier integrity by regulating Claudin-1 and synaptopodin expression, limits pro-inflammatory cytokines (IL-6, IL-12), and inhibits oncogenic pathways (Akt/ERK, Wnt, and TGF-β signaling). Colonic butyrate producers shape the gut microbial community by secreting various anti-microbial substances, such as cathelicidins, reuterin, and β-defensin-1, and maintain gut homeostasis by releasing anti-inflammatory molecules, such as IgA, vitamin B, and microbial anti-inflammatory molecules. Additionally, butyrate producers, such as Roseburia, produce anti-carcinogenic metabolites, such as shikimic acid and a precursor of conjugated linoleic acid. In this review, we summarized the significance of butyrate, critically examined the role and relevance of butyrate producers, and contextualized their importance as microbial therapeutics.

Fructooligosaccharides (FOS) differentially modifies the in vitro gut microbiota in an age-dependent manner

Introduction

Fructooligosaccharides (FOS) are well-known carbohydrates that promote healthy gut microbiota and have been previously demonstrated to enhance levels of Bifidobacterium and Lactobacillus. Its bifidogenic properties are associated with positive health outcomes such as reduced obesity and anti-inflammatory properties, and, therefore, is in use as a prebiotic supplement to support healthy gut microbiota. However, the gut microbiota changes with age, which may lead to differential responses to treatments with prebiotics and other dietary supplements.

Methods

To address this concern, we implemented a 24-h in vitro culturing method to determine whether FOS treatment in three different adult age groups would have a differential effect. The age groups of interest ranged from 25 to 70 years and were split into young adults, adults, and older adults for the purposes of this analysis. Metagenomics and short-chain fatty acid analysis were performed to determine changes in the structure and function of the microbial communities.

Results

These analyses found that FOS created a bifidogenic response in all age groups, increased overall SCFA levels, decreased alpha diversity, and shifted the communities to be more similar in beta diversity metrics. However, the age groups differed in which taxa were most prevalent or most affected by FOS treatment.

Discussion

Overall, the results of this study demonstrate the positive effects of FOS on the gut microbiome, and importantly, how age may play a role in the effectiveness of this prebiotic.

Microbiome and Human Health: Current Understanding, Engineering, and Enabling Technologies

The human microbiome is composed of a collection of dynamic microbial communities that inhabit various anatomical locations in the body. Accordingly, the coevolution of the microbiome with the host has resulted in these communities playing a profound role in promoting human health. Consequently, perturbations in the human microbiome can cause or exacerbate several diseases. In this Review, we present our current understanding of the relationship between human health and disease development, focusing on the microbiomes found across the digestive, respiratory, urinary, and reproductive systems as well as the skin. We further discuss various strategies by which the composition and function of the human microbiome can be modulated to exert a therapeutic effect on the host. Finally, we examine technologies such as multiomics approaches and cellular reprogramming of microbes that can enable significant advancements in microbiome research and engineering.

Manipulating the Gut Microbiome as a Therapeutic Strategy to Mitigate Late Effects in Childhood Cancer Survivors

Recent studies have identified causal links between altered gut microbiome, chronic inflammation, and inflammation-driven conditions such as diabetes and cardiovascular disease. Childhood cancer survivors (CCS) show late effects of therapy in the form of inflammaging-related disorders as well as microbial dysbiosis, supporting a hypothesis that the conditions are interconnected. Given the susceptibility of the gut microbiome to alteration, a number of therapeutic interventions have been investigated for the treatment of inflammatory conditions, though not within the context of cancer survivorship in children and adolescents. Here, we evaluate the potential for these interventions, which include probiotic supplementation, prebiotics/fiber-rich diet, exercise, and fecal microbiota transplantation for prevention and treatment of cancer treatment-related microbial dysbiosis in survivors. We also make recommendations to improve adherence and encourage long-term lifestyle changes for maintenance of healthy gut microbiome in CCS as a potential strategy to mitigate treatment-related late effects.

Previous gut microbiota has an effect on postprandial insulin response after intervention with yacon syrup as a source of fructooligosaccharides: a randomized, crossover, double-blind clinical trial

OBJECTIVES

The use of prebiotics has an effect on postprandial glucose and insulin concentrations; however, the interaction between the previous profile of the intestinal microbiota and the effect of supplementation with prebiotics is not clear. Our objective was to evaluate the effect of previous intestinal microbiota profile on the postprandial insulin response to yacon syrup, used as a source of fructooligosaccharides (FOSs), in young women. The product presents high levels of FOS.

METHODS

In this double-blind, crossover, randomized clinical trial, 40 adult women were allocated to receive a breakfast containing 40 g of yacon syrup (14 g FOS, intervention A) or a breakfast containing 40 g of placebo (intervention B). On each intervention day, after 12 h of fasting, an aliquot of blood was collected for insulin analysis at 0, 15, 30, 45, 60, 90, and 120 min. The fecal sample was collected before the beginning of the interventions, and the DNA was extracted and quantified, with subsequent amplification of the 16S region, next-generation sequencing, and analysis of sequencing data.

RESULTS

The glucose and insulin concentrations were reduced after ingestion of yacon syrup compared with placebo, specifically at the 30 min to insulin. After the receiver operating characteristic analysis, six volunteers who did not respond to the yacon consumption intervention were identified. The abundance of the phylum Actinobacteria (P = 0.021) and the order Bifidobacteriales (P = 0.013) were positively associated with better insulin response. Other main phyla were not associated with intervention response.

CONCLUSIONS

The previous profile of the intestinal microbiota has an effect on the postprandial insulin response to FOSs, mainly in the phylum Actinobacteria and Bifidobacteriales order.

Dietary Fiber Intake and Gut Microbiota in Human Health

Dietary fiber is fermented by the human gut microbiota, producing beneficial microbial metabolites, such as short-chain fatty acids. Over the last few centuries, dietary fiber intake has decreased tremendously, leading to detrimental alternations in the gut microbiota. Such changes in dietary fiber consumption have contributed to the global epidemic of obesity, type 2 diabetes, and other metabolic disorders. The responses of the gut microbiota to the dietary changes are specific to the type, amount, and duration of dietary fiber intake. The intricate interplay between dietary fiber and the gut microbiota may provide clues for optimal intervention strategies for patients with type 2 diabetes and other noncommunicable diseases. In this review, we summarize current evidence regarding dietary fiber intake, gut microbiota modulation, and modification in human health, highlighting the type-specific cutoff thresholds of dietary fiber for gut microbiota and metabolic outcomes.

The microbiome's fiber degradation profile and its relationship with the host diet

BACKGROUND

The relationship between the gut microbiome and diet has been the focus of numerous recent studies. Such studies aim to characterize the impact of diet on the composition of the microbiome, as well as the microbiome's ability to utilize various compounds in the diet and produce metabolites that may be beneficial for the host. Consumption of dietary fibers (DFs)-polysaccharides that cannot be broken down by the host's endogenous enzymes and are degraded primarily by members of the microbiome-is known to have a profound effect on the microbiome. Yet, a comprehensive characterization of microbiome compositional and functional shifts in response to the consumption of specific DFs is still lacking.

RESULTS

Here, we introduce a computational framework, coupling metagenomic sequencing with careful annotation of polysaccharide degrading enzymes and DF structures, for inferring the metabolic ability of a given microbiome sample to utilize a broad catalog of DFs. We demonstrate that the inferred fiber degradation profile (IFDP) generated by our framework accurately reflects the dietary habits of various hosts across four independent datasets. We further demonstrate that IFDPs are more tightly linked to the host diet than commonly used taxonomic and functional microbiome-based profiles. Finally, applying our framework to a set of ~700 metagenomes that represents large human population cohorts from 9 different countries, we highlight intriguing global patterns linking DF consumption habits with microbiome capacities.

CONCLUSIONS

Combined, our findings serve as a proof-of-concept for the use of DF-specific analysis for providing important complementary information for better understanding the relationship between dietary habits and the gut microbiome.

Effects of iron deficiency and iron supplementation at the host-microbiota interface: Could a piglet model unravel complexities of the underlying mechanisms?

Iron deficiency is the most prevalent human micronutrient deficiency, disrupting the physiological development of millions of infants and children. Oral iron supplementation is used to address iron-deficiency anemia and reduce associated stunting but can promote infection risk since restriction of iron availability serves as an innate immune mechanism against invading pathogens. Raised iron availability is associated with an increase in enteric pathogens, especially Enterobacteriaceae species, accompanied by reductions in beneficial bacteria such as Bifidobacteria and lactobacilli and may skew the pattern of gut microbiota development. Since the gut microbiota is the primary driver of immune development, deviations from normal patterns of bacterial succession in early life can have long-term implications for immune functionality. There is a paucity of knowledge regarding how both iron deficiency and luminal iron availability affect gut microbiota development, or the subsequent impact on immunity, which are likely to be contributors to the increased risk of infection. Piglets are naturally iron deficient. This is largely due to their low iron endowments at birth (primarily due to large litter sizes), and their rapid growth combined with the low iron levels in sow milk. Thus, piglets consistently become iron deficient within days of birth which rapidly progresses to anemia in the absence of iron supplementation. Moreover, like humans, pigs are omnivorous and share many characteristics of human gut physiology, microbiota and immunity. In addition, their precocial nature permits early maternal separation, individual housing, and tight control of nutritional intake. Here, we highlight the advantages of piglets as valuable and highly relevant models for human infants in promoting understanding of how early iron status impacts physiological development. We also indicate how piglets offer potential to unravel the complexities of microbiota-immune responses during iron deficiency and in response to iron supplementation, and the link between these and increased risk of infectious disease.

Age-Related NAFLD: The Use of Probiotics as a Supportive Therapeutic Intervention

Human aging, a natural process characterized by structural and physiological changes, leads to alterations of homeostatic mechanisms, decline of biological functions, and subsequently, the organism becomes vulnerable to external stress or damage. In fact, the elderly population is prone to develop diseases due to deterioration of physiological and biological systems. With aging, the production of reactive oxygen species (ROS) increases, and this causes lipid, protein, and DNA damage, leading to cellular dysfunction and altered cellular processes. Indeed, oxidative stress plays a key role in the pathogenesis of several chronic disorders, including hepatic diseases, such as non-alcoholic fatty liver disease (NAFLD). NAFLD, the most common liver disorder in the Western world, is characterized by intrahepatic lipid accumulation; is highly prevalent in the aging population; and is closely associated with obesity, insulin resistance, hypertension, and dyslipidemia. Among the risk factors involved in the pathogenesis of NAFLD, the dysbiotic gut microbiota plays an essential role, leading to low-grade chronic inflammation, oxidative stress, and production of various toxic metabolites. The intestinal microbiota is a dynamic ecosystem of microbes involved in the maintenance of physiological homeostasis; the alteration of its composition and function, during aging, is implicated in different liver diseases. Therefore, gut microbiota restoration might be a complementary approach for treating NAFLD. The administration of probiotics, which can relieve oxidative stress and elicit several anti-aging properties, could be a strategy to modify the composition and restore a healthy gut microbiota. Indeed, probiotics could represent a valid supplement to prevent and/or help treating some diseases, such as NAFLD, thus improving the already available pharmacological intervention. Moreover, in aging, intervention of prebiotics and fecal microbiota transplantation, as well as probiotics, will provide novel therapeutic approaches. However, the relevant research is limited, and several scientific research works need to be done in the near future to confirm their efficacy.

Validity of food additive maltodextrin as placebo and effects on human gut physiology: systematic review of placebo-controlled clinical trials

PURPOSE

Maltodextrin (MDX) is a polysaccharide food additive commonly used as oral placebo/control to investigate treatments/interventions in humans. The aims of this study were to appraise the MDX effects on human physiology/gut microbiota, and to assess the validity of MDX as a placebo-control.

METHODS

We performed a systematic review of randomized-placebo-controlled clinical trials (RCTs) where MDX was used as an orally consumed placebo. Data were extracted from study results where effects (physiological/microbial) were attributed (or not) to MDX, and from study participant outcomes data, before-and-after MDX consumption, for post-publication 're-analysis' using paired-data statistics.

RESULTS

Of two hundred-sixteen studies on 'MDX/microbiome', seventy RCTs (n = 70) were selected for analysis. Supporting concerns regarding the validity of MDX as a placebo, the majority of RCTs (60%, CI 95% = 0.48-0.76; n = 42/70; Fisher-exact p = 0.001, expected < 5/70) reported MDX-induced physiological (38.1%, n = 16/42; p = 0.005), microbial metabolite (19%, n = 8/42; p = 0.013), or microbiome (50%, n = 21/42; p = 0.0001) effects. MDX-induced alterations on gut microbiome included changes in the Firmicutes and/or Bacteroidetes phyla, and Lactobacillus and/or Bifidobacterium species. Effects on various immunological, inflammatory markers, and gut function/permeability were also documented in 25.6% of the studies (n = 10/42). Notably, there was considerable variability in the direction of effects (decrease/increase), MDX dose, form (powder/pill), duration, and disease/populations studied. Overall, only 20% (n = 14/70; p = 0.026) of studies cross-referenced MDX as a justifiable/innocuous placebo, while 2.9% of studies (n = 2/70) acknowledged their data the opposite.

CONCLUSION

Orally-consumed MDX often (63.9% of RCTs) induces effects on human physiology/gut microbiota. Such effects question the validity of MDX as a placebo-control in human clinical trials.

Gut microbiota: Linking nutrition and perinatal depression

Perinatal depression is a mood disorder that is reported in women during pregnancy (prenatal) and after childbirth (postnatal). The onset of perinatal depression is associated with changes in reproductive hormones, stress hormones and neurosteroids. These chemical compounds can be modulated by the gut microbiota, which may affect maternal mental health during the perinatal period via the gut-brain-axis. Recent studies suggest that nutritional and dietary interventions (vitamin D, ω-3 fatty acids, iron, and fiber) effectively prevent or mitigate maternal depression and anxiety, but their efficacy is confounded by various factors, including the gut microbiota. Probiotics are efficacious in maintaining microbiota homeostasis, and thus, have the potential to modulate the development of perinatal mood disorders, despite no evidence in human. Therefore, clinical trials are warranted to investigate the role of probiotic supplementation in perinatal depression and behavioral changes. This article reviews the interplay between nutrition, gut microbiota and mood and cognition, and the evidence suggesting that probiotics affect the onset and development of perinatal depression.

Effect of Fructooligosaccharides Supplementation on the Gut Microbiota in Human: A Systematic Review and Meta-Analysis

Background: Numerous studies have investigated the effects of the supplementation of fructooligosaccharides (FOS) on the number of bacteria in the gut that are good for health, but the results have been inconsistent. Additionally, due to its high fermentability, supplementation of FOS may be associated with adverse gastrointestinal symptoms such as bloating and flatulence. Therefore, we assessed the effects of FOS interventions on the composition of gut microbiota and gastrointestinal symptoms in a systematic review and meta-analysis. Design: All randomized controlled trials published before 10 July 2022 that investigated the effects of FOS supplementation on the human gut microbiota composition and gastrointestinal symptoms and met the selection criteria were included in this study. Using fixed or random-effects models, the means and standard deviations of the differences between the two groups before and after the intervention were combined into weighted mean differences using 95% confidence intervals (CIs). Results: Eight studies containing 213 FOS supplements and 175 controls remained in this meta-analysis. Bifidobacterium spp. counts significantly increased during FOS ingestion (0.579, 95% CI: 0.444−0.714) in comparison with that of the control group. Subgroup analysis showed greater variation in Bifidobacterium spp. in adults (0.861, 95% CI: 0.614−1.108) than in infants (0.458, 95% CI: 0.297−0.619). The increase in Bifidobacterium spp. counts were greater in the group with an intervention duration greater than 4 weeks (0.841, 95% CI: 0.436−1.247) than an intervention time less than or equal to four weeks (0.532, 95% CI: 0.370−0.694), and in the group with intervention doses > 5 g (1.116, 95% CI: 0.685−1.546) the counts were higher than those with doses ≤ 5 g (0.521, 95% CI: 0.379−0.663). No differences in effect were found between FOS intervention and comparators in regard to the abundance of other prespecified bacteria or adverse gastrointestinal symptoms. Conclusions: This is the first meta-analysis to explore the effect of FOS on gut microbiota and to evaluate the adverse effects of FOS intake on the gastrointestinal tract. FOS supplementation could increase the number of colonic Bifidobacterium spp. while higher dose (7.5−15 g/d) and longer duration (>4 weeks) showed more distinct effects and was well tolerated.

Review article: the future of microbiome-based therapeutics

BACKGROUND

From consumption of fermented foods and probiotics to emerging applications of faecal microbiota transplantation, the health benefit of manipulating the human microbiota has been exploited for millennia. Despite this history, recent technological advances are unlocking the capacity for targeted microbial manipulation as a novel therapeutic.

AIM

This review summarises the current developments in microbiome-based medicines and provides insight into the next steps required for therapeutic development.

METHODS

Here we review current and emerging approaches and assess the capabilities and weaknesses of these technologies to provide safe and effective clinical interventions. Key literature was identified through Pubmed searches with the following key words, 'microbiome', 'microbiome biomarkers', 'probiotics', 'prebiotics', 'synbiotics', 'faecal microbiota transplant', 'live biotherapeutics', 'microbiome mimetics' and 'postbiotics'.

RESULTS

Improved understanding of the human microbiome and recent technological advances provide an opportunity to develop a new generation of therapies. These therapies will range from dietary interventions, prebiotic supplementations, single probiotic bacterial strains, human donor-derived faecal microbiota transplants, rationally selected combinations of bacterial strains as live biotherapeutics, and the beneficial products or effects produced by bacterial strains, termed microbiome mimetics.

CONCLUSIONS

Although methods to identify and refine these therapeutics are continually advancing, the rapid emergence of these new approaches necessitates accepted technological and ethical frameworks for measurement, testing, laboratory practices and clinical translation.

Effects of Inulin-Based Prebiotics Alone or in Combination with Probiotics on Human Gut Microbiota and Markers of Immune System: A Randomized, Double-Blind, Placebo-Controlled Study in Healthy Subjects

The gut microbiota is implicated in diverse interactions affecting human health. The present study reports a randomized, double-blind, placebo-controlled clinical study conducted by administering a new synbiotic formulation composed of two Lactobacillus strains (L. plantarum and L. acidophilus) and one Bifidobacterium strain (B. animalis subsp. lactis) and two types of fructans (fructo-oligosaccharides with a degree of polymerization of 3–5 and inulin-type fructans with 10 DP). The effects of this synbiotic were evaluated on healthy subjects for 28 days and the maintenance of its efficacy was evaluated at the end of a follow-up period of 28 days. The synbiotic treatment contributes to higher biodiversity of the gut microbiota, increasing the community richness with respect to the group with the prebiotics alone and the placebo group. Its positive effect is also reflected in the variation of microbial community structure favoring the beneficial short-chain fatty acids bacterial producers. The amelioration of the health status of the subjects was also established by the reduction of common infectious disease symptom incidence, the stimulation of the gut immune system showing a noteworthy variation of fecal β-defensin2 and calprotectin levels, and the modulation of the response of the respiratory tract’s immune system by salivary IgA as well as total antioxidant capacity biomarkers.

Rapid, real-time sucrase characterization: Showcasing the feasibility of a one-pot activity assay

Sucrases can modify numerous carbohydrates, and short-chain oligosaccharides produced by the unique transfructosylation activity of levansucrases are promising candidates for the growing sugar substitute market. These compounds could counteract the increasing number of diseases associated with the consumption of high-calorie sugars. Thus, there is great interest in the characterization of novel levansucrases. The commonly used method for sucrase activity determination is to quantify d-glucose released in the sucrose-splitting reaction. This is usually done in a discontinuous mode, i.e., several samples taken from the sucrase reaction are applied to a separately performed d-glucose determination (e.g., GOPOD assay). Employing the newly isolated levansucrase LevS_KK21 from Pseudomonas sp. KK21, the feasibility of a one-pot sucrase characterization was investigated by combining sucrase reaction and GOPOD-based d-glucose determination into a single, continuous assay (Real-time GOPOD). The enzyme was characterized with respect to kinetic parameters, ion dependency, pH value, and reaction temperature in a comparative approach employing Real-time GOPOD and HPLC. High data consistency for all investigated enzyme parameters demonstrated that current processes for sucrase characterization can be considerably accelerated by the continuous assay while maintaining data validity. However, the assay was not applicable at acidic pH, as decolorization of the quinoneimine dye formed during the GOPOD reaction was observed. Overall, the study presents valuable data on the potentials of real-time sucrase activity assessment for an accelerated discovery and characterization of interesting enzymes such as the hereby introduced levansucrase LevS_KK21. Progress in sucrase discovery will finally foster the development of health-promoting sucrose substitutes.

The impact of prebiotic fructooligosaccharides on gut dysbiosis and inflammation in obesity and diabetes related kidney disease

Obesity is an extensive health problem worldwide that is frequently associated with diabetes. It is a risk factor for the development of several diseases including diabetic nephropathy. Recent studies have reported that gut dysbiosis aggravates the progression of obesity and diabetes by increasing the production of uremic toxins in conjunction with gut barrier dysfunction which then leads to increased passage of lipopolysaccharides (LPS) into the blood circulatory system eventually causing systemic inflammation. Therefore, the modification of gut microbiota using a prebiotic supplement may assist in the restoration of gut barrier function and reduce any disturbance of the inflammatory response. In this review information has been compiled concerning the possible mechanisms involved in an increase in obesity, diabetes and kidney dysfunction via the exacerbation of the inflammatory response and its association with gut dysbiosis. In addition, the role of fructooligosaccharides (FOS), a source of prebiotic widely available commercially, on the improvement of gut dysbiosis and attenuation of inflammation on obese and diabetic conditions has been reviewed. The evidence confirms that FOS supplementation could improve the pathological changes associated with obesity and diabetes related kidney disease, however, knowledge concerning the mechanisms involved is still limited and needs further elucidation.

Exercise and Prebiotic Fiber Provide Gut Microbiota-Driven Benefit in a Survivor to Germ-Free Mouse Translational Model of Breast Cancer

Simple Summary

Breast cancer is the most common cancer in women worldwide. In recent years, the community of microbes that inhabit the intestinal tract, called the gut microbiota, has been shown to influence patient response to several cancer therapies. On the other hand, treatments such as chemotherapy can disrupt the resident gut microbiota and potentially contribute to poor health outcomes. Strategies to improve the composition of the gut microbiota include dietary and exercise interventions. While diet and exercise are already established as important for breast cancer prevention, during treatment, and for reducing recurrence, little is known about the impact of these factors on the gut microbiota in the context of breast cancer. Therefore, our aim was to examine the impact of exercise and diet on the gut microbiota in breast cancer. Our findings indicate that exercise and prebiotic fiber supplementation may provide benefits to individuals with breast cancer through advantageous gut microbial changes. Our findings of a potential adjuvant of exercise and prebiotics should inspire further mechanistic and clinical investigations.

Abstract

The gut microbiota plays a role in shaping overall host health and response to several cancer treatments. Factors, such as diet, exercise, and chemotherapy, can alter the gut microbiota. In the present study, the Alberta Cancer Exercise (ACE) program was investigated as a strategy to favorably modify the gut microbiota of breast cancer survivors who had received chemotherapy. Subsequently, the ability of post-exercise gut microbiota, alone or with prebiotic fiber supplementation, to influence breast cancer outcomes was interrogated using fecal microbiota transplant (FMT) in germ-free mice. While cancer survivors experienced little gut microbial change following ACE, in the mice, tumor volume trended consistently lower over time in mice colonized with post-exercise compared to pre-exercise microbiota with significant differences on days 16 and 22. Beta diversity analysis revealed that EO771 breast tumor cell injection and Paclitaxel chemotherapy altered the gut microbial communities in mice. Enrichment of potentially protective microbes was found in post-exercise microbiota groups. Tumors of mice colonized with post-exercise microbiota exhibited more favorable cytokine profiles, including decreased vascular endothelial growth factor (VEGF) levels. Beneficial microbial and molecular outcomes were augmented with prebiotic supplementation. Exercise and prebiotic fiber demonstrated adjuvant action, potentially via an enhanced anti-tumor immune response modulated by advantageous gut microbial shifts.

Associations between the gut microbiome, gut microbiology and heart failure: Current understanding and future directions

The role of the gut microbiome in pathophysiology, prognostication and clinical management of heart failure (HF) patients is of great clinical and research interest. Both preclinical and clinical studies have shown promising results, and the gut microbiome has been implicated in other cardiovascular conditions that are risk factors for HF. There is an increasing interest in the use of biological compounds produced as biomarkers for prognostication as well as exploration of therapeutic options targeting the various markers and pathways from the gut microbiome that are implicated in HF. However, study variations exist, and targeted research for individual putative biomarkers is necessary. There is also limited evidence pertaining to decompensated HF in particular. In this review, we synthesize current understandings around pathophysiology, prognostication and clinical management of heart failure (HF) patients, and also provide an outline of potential areas of future research and scientific advances.

Effective Regulation of Gut Microbiota With Probiotics and Prebiotics May Prevent or Alleviate COVID-19 Through the Gut-Lung Axis

Coronavirus disease 2019 (COVID-19) can disrupt the gut microbiota balance, and patients usually have intestinal disorders. The intestine is the largest immune organ of the human body, and gut microbes can affect the immune function of the lungs through the gut-lung axis. Many lines of evidence support the role of beneficial bacteria in enhancing human immunity, preventing pathogen colonization, and thereby reducing the incidence and severity of infection. In this article, we review the possible approach of modulating microbiota to help prevent and treat respiratory tract infections, including COVID-19, and discuss the possibility of using probiotics and prebiotics for this purpose. We also discuss the mechanism by which intestinal micro-flora regulate immunity and the effects of probiotics on the intestinal micro-ecological balance. Based on this understanding, we propose the use of probiotics and prebiotics to modulate gut microbiota for the prevention or alleviation of COVID-19 through the gut-lung axis.

FODMAPs, inflammatory bowel disease and gut microbiota: updated overview on the current evidence

PURPOSE

Based on the fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) hypothesis, the low-FODMAP diet has been suggested as a potential therapeutic approach for inflammatory bowel disease (IBD) with promising results on disease management. However, this diet implies a specific broad food restriction, which potentially increases the risk of nutritional deficiencies and may aggravate gut microbiota dysbiosis of IBD patients. The aim of the present study is to review the effect of individual FODMAPs on the human gut microbiota. In addition, this narrative review provides an updated overview of the use of the low-FODMAP diet in IBD, namely the implementation, advantages, limitations, and the impact on the gut microbiota.

METHODS

The literature search strategy was applied to PubMed and Web of Science using relevant keywords, IBD, FODMAPs, Fructose, Lactose, Polyols, FOS, GOS, low-FODMAP diet and gut microbiota.

RESULTS

Current data suggest that the low-FODMAP diet may effectively improve clinical outcomes in the management of IBD and ensure better quality of life for IBD patients. However, there is evidence highlighting some issues of concern, particularly the adequacy of the diet and the impact on the gut microbiota. The various FODMAP types differently modulate the gut microbiota.

CONCLUSION

IBD management should be achieved with the least possible dietary restriction to avoid detrimental consequences, particularly on nutritional adequacy and gut microbiota. Thus, it is important to individualize and monitor the nutrition intervention. Further studies are required to better characterize the relationship between diet, the gut microbiota, and IBD to support the generalization of this approach for clinical practice in IBD therapy and management.

Enterotype-Specific Effect of Human Gut Microbiota on the Fermentation of Marine Algae Oligosaccharides: A Preliminary Proof-of-Concept In Vitro Study

The human gut microbiota plays a critical role in the metabolism of dietary carbohydrates. Previous studies have illustrated that marine algae oligosaccharides could be utilized and readily fermented by human gut microbiota. However, the human gut microbiota is classified into three different enterotypes, and how this may affect the fermentation processes of marine algae oligosaccharides has not been studied. Here, using in vitro fermentation and 16 S high-throughput sequencing techniques, we demonstrate that the human gut microbiota has an enterotype-specific effect on the fermentation outcomes of marine algae oligosaccharides. Notably, microbiota with a Bacteroides enterotype was more proficient at fermenting carrageenan oligosaccharides (KOS) as compared to that with a Prevotella enterotype and that with an Escherichia enterotype. Interestingly, the prebiotic effects of marine algae oligosaccharides were also found to be enterotype dependent. Altogether, our study demonstrates an enterotype-specific effect of human gut microbiota on the fermentation of marine algae oligosaccharides. However, due to the availability of the fecal samples, only one sample was used to represent each enterotype. Therefore, our research is a proof-of-concept study, and we anticipate that more detailed studies with larger sample sizes could be conducted to further explore the enterotype-specific prebiotic effects of marine oligosaccharides.

Impact of dietary fructooligosaccharides (FOS) on murine gut microbiota and intestinal IgA secretion

Fructooligosaccharides (FOS) are considered as prebiotics and are well known for their health-promoting properties, including antitumor, allergy-preventive, and infection-protective effects. They exert these effects by modulating the gut microbial composition and dynamics. In the present study, we performed a comparative whole metagenome shotgun sequencing analysis (WMGS) to elucidate the gut microbiota and secretary Immunoglobulin A (SIgA) dynamics as a result of 5% (w/w) FOS supplementation over a period of 7 days (fecal samples were collected every day). A number of taxa including Bacteroides, Lactobacillus, Roseburia, Clostridia, Faecalibaculum, and Enterorhabdus were found to be modulated with SIgA production in the murine gut. The process of SIgA production from FOS metabolization was found to be carried out via the production of short-chain fatty acids in the gut. Species of Bacteroides and Roseburia; namely, B. caccae, B. finegoldii, B. ovatus, B. thetaiotamicron, and Roseburia intestinalis, respectively, are predominantly responsible for FOS metabolization in the murine gut. The abundances of these bacterial species and their corresponding functions involved in FOS metabolization decreased over time even though these prebiotics were administered continuously for seven days. This suggests that there is a decrease in FOS metabolization over time. In addition, the present analysis suggests that the administration of FOS may help to reduce the pathogenic bacteria from the gut via SIgA production.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-022-03116-3.