Adherence to unhealthy diets is associated with altered frontal gamma-aminobutyric acid and glutamate concentrations and grey matter volume: preliminary findings.

OBJECTIVES: Common mental disorders (CMD) are associated with impaired frontal excitatory/inhibitory (E/I) balance and reduced grey matter volume (GMV). Larger GMV (in the areas that are implicated in CMD-pathology) and improved CMD-symptomatology have been observed in individuals who adhere to high quality diets. Moreover, preclinical studies have shown altered neurometabolites (primarily gamma-aminobutyric acid: GABA and glutamate: GLU) in relation to diet quality. However, neurochemical correlates of diet quality and how these neurobiological changes are associated with CMD and with its transdiagnostic factor, rumination, is unknown in humans. Therefore, in this study, we examined the associations between diet quality and frontal cortex neuro-chemistry and structure, as well as CMD and rumination in humans. METHODS: Thirty adults were classified into high and low diet quality groups and underwent 1H-MRS to measure medial prefrontal cortex (mPFC) metabolite concentrations and volumetric imaging to measure GMV. RESULTS: Low (vs High) diet quality group had reduced mPFC-GABA and elevated mPFC-GLU concentrations, as well as reduced right precentral gyrus (rPCG) GMV. However, CMD and rumination were not associated with diet quality. Notably, we observed a significant negative correlation between rumination and rPCG-GMV and a marginally significant association between rumination and mPFC-GLU concentrations. There was also a marginally significant association between mPFC-GLU concentrations and rPCG-GMV. DISCUSSION: Adhering to unhealthy dietary patterns may be associated with compromised E/I balance, and this could affect GMV, and subsequently, rumination.

Supplementation with postbiotic from Bifidobacterium Breve BB091109 improves inflammatory status and endocrine function in healthy females: a randomized, double-blind, placebo-controlled, parallel-groups study.

This study evaluated the effects of dietary supplementation with a postbiotic extract of Bifidobacterium breve BB091109 on pro-inflammatory cytokines levels and markers of endocrine function. A prospective, double-blind, placebo-controlled, randomized, single-centered, parallel study was conducted on a group of 40-55-year-old females. The study included 30 healthy females, divided into two groups: a supplement (n = 20) and a placebo (n = 10) groups. Blood and saliva samples were collected at baseline (wk0), after 4 weeks (wk 4) and 12 weeks (12wk) of daily supplementation (500 mg), and 4 weeks (wk 16) after termination of supplementation. The levels of fasting CRP, IL-6, IL-10, TNF-α, IFN-γ, DHEA, estradiol, estriol, progesterone, cortisol and human growth hormone were analysed. The results revealed a significant effect of the 90-day supplementation with B. breve postbiotic extract on changes in CRP, IL-6 levels, DHEA, estradiol and estriol. In conclusion, the supplementation with the B. breve postbiotic extract improved endocrine function in females over 40 years old and induced protective changes in inflammatory markers. These findings highlight the potential health benefits of this supplementation in promoting hormonal balance and reducing inflammation in this population.

The gut microbiome meets nanomaterials: exposure and interplay with graphene nanoparticles.

Graphene-based nanoparticles are widely applied in many technology and science sectors, raising concerns about potential health risks. Emerging evidence suggests that graphene-based nanomaterials may interact with microorganisms, both pathogens and commensal bacteria, that dwell in the gut. This review aims to demonstrate the current state of knowledge on the interplay between graphene nanomaterials and the gut microbiome. In this study, we briefly overview nanomaterials, their usage and the characteristics of graphene-based nanoparticles. We present and discuss experimental data from in vitro studies, screening tests on small animals and rodent experiments related to exposure and the effects of graphene nanoparticles on gut microbiota. With this in mind, we highlight the reported crosstalk between graphene nanostructures, the gut microbial community and the host immune system in order to shed light on the perspective to bear on the biological interactions. The studies show that graphene-based material exposure is dosage and time-dependent, and different derivatives present various effects on host bacteria cells. Moreover, the route of graphene exposure might influence a shift in the gut microbiota composition, including the alteration of functions and diversity and abundance of specific phyla or genera. However, the mechanism of graphene-based nanomaterials' influence on gut microbiota is poorly understood. Accordingly, this review emphasises the importance of studies needed to establish the most desirable synthesis methods, types of derivatives, properties, and safety aspects mainly related to the routes of exposure and dosages of graphene-based nanomaterials.

Cooking, Digestion, and In Vitro Colonic Fermentation of Nigerian Wholegrains Affect Phenolic Acid Metabolism and Gut Microbiota Composition.

Wholegrains contain both fibre and phenolic acids (PAs), and their gastrointestinal modifications are critical for their bioavailability and bioactivity. We evaluated the modifications on the PA profile and gut microbiota composition of selected Nigerian wholegrains, following cooking and gastrointestinal digestion. Red fonio, red millet, red sorghum, and white corn were cooked, digested, and fermented using an in vitro colonic model. A total of 26 PA derivatives were quantified in soluble and bound fractions using Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) analysis. DNA samples were analysed using 16S rRNA amplicon sequencing to profile the microbiota composition. The results show that cooking and digestion significantly affected the levels of PAs in all grains (p ≤ 0.05) compared to raw grains. Colonic fermentation resulted in a peak of total soluble PAs at 4-6 h for red sorghum and white corn and at 24 h for red millet and red fonio. Enterobacteriaceae genera were the most abundant at 24 h in all grains studied. 3-hydroxybenzaldehyde correlated positively with the relative abundance of Dorea and the mucus-degrader bacteria Akkermansia (p ≤ 0.05), whereas hydroferulic acid and isoferulic acid levels correlated negatively with Oscillospira and Ruminococcus (p ≤ 0.05), respectively. Our data indicate that cooking, digestion, and colonic fermentation affect the release of bound PAs from wholegrains and, consequently, their metabolic conversion. Furthermore, PA fermentation in the gut is associated with potentially relevant changes in the microbiota. This in vitro study provides the basis for the design of an in vivo human intervention study that can confirm the trends herein observed but also assess the impact on health outcomes.

Personality, dietary identity, mental and sleep health in vegans and vegetarians: A preliminary cross-sectional study.

Background and Aims: Plant-based diets have gained popularity over the past decade. However, research regarding mental and sleep health benefits of following plant-based diets are conflicting. As there are associations between mental/sleep health and various personality traits, and personality may differ between individuals who follow different diets, in this preliminary study, we examined the associations between mental and sleep health and (i) personality and (ii) dietary identity in individuals who follow vegan and vegetarian diets. Methods: Cross-sectional data on sociodemographic, personality traits, dietarian identity, overall mental health, depression, anxiety, stress, and sleep quality were collected from 57 vegan/vegetarian participants between the ages of 18-40. Results: After controlling for various sociodemographic and lifestyle factors, linear regression models revealed that (i) higher dietarian private regard was a significant predictor of better overall mental health, (ii) lower levels of extraversion and higher levels of empathy predicted depression, (iii) higher levels of neuroticism and empathy predicted anxiety, (iv) higher levels of neuroticism, dietarian centrality, and neuroticism × centrality predicted stress, (v) higher levels of conscientiousness, lower levels of dietarian centrality, but higher levels of personal motivation and dietary strictness, as well as conscientiousness × centrality, conscientiousness × personal motivation, and conscientiousness × strictness predicted better sleep quality. Conclusions: These preliminary findings suggest that not only personality traits, but also dietary identity was indeed related to mental and sleep health in individuals who follow plant-based diets.

Comparison of the relative impacts of acute consumption of an inulin-enriched diet, milk kefir or a commercial probiotic product on the human gut microbiome and metabolome.

It has been established that the human gut microbiota is central to health, and, consequently, there has been a growing desire to positively modulate its composition and/or function through, for example, the use of fermented foods, prebiotics or probiotics. Here, we compare the relative impact of the daily consumption of an inulin-enriched diet (n = 10), a commercial probiotic-containing fermented milk product (FMP) (n = 10), or a traditional kefir FMP (n = 9), over a 28-day period on the gut microbiome and urine metabolome of healthy human adults. None of the treatments resulted in significant changes to clinical parameters or biomarkers tested. However, shotgun metagenomic analysis revealed that kefir consumption resulted in a significant change in taxonomy, in the form of an increased abundance of the sub-dominant FMP-associated species Lactococcus raffinolactis, which further corresponded to shifts in the urine metabolome. Overall, our results indicated that daily consumption of a single portion of kefir alone resulted in detectable changes to the gut microbiota and metabolome of consumers.

Cerrado and Pantanal fruit flours affect gut microbiota composition in healthy and post-COVID-19 individuals: an in vitro pilot fermentation study.

Cerrado and Pantanal plants can provide fruits with high nutritional value and antioxidants. This study aims to evaluate four fruit flours (from jatobá pulp, cumbaru almond, bocaiuva pulp and bocaiuva almond) and their effects on the gut microbiota in healthy (HD) and post-COVID-19 individuals (PC). An in vitro batch system was carried out, the microbiota was analysed by 16S rRNA amplicon sequencing and the short-chain fatty acids ratio was determined. Furthermore, the effect of jatobá pulp flour oil (JAO) on cell viability, oxidative stress and DNA damage was investigated in a myelo-monocytic cell line. Beyond confirming a microbiota imbalance in PC, we identified flour-specific effects: (i) reduction of Veillonellaceae with jatobá extract in PC samples; (ii) decrease in Akkermansia with jatoba and cumbaru flours; (iii) decreasing trend of Faecalibacterium and Ruminococcus with all flours tested, with the exception of the bocaiuva almond in HD samples for Ruminococcus and (iv) increase in Lactobacillus and Bifidobacterium in PC samples with bocaiuva almond flour. JAO displayed antioxidant properties protecting cells from daunorubicin-induced cytotoxicity, oxidative stress and DNA damage. The promising microbiota-modulating abilities of some flours and the chemopreventive effects of JAO deserve to be further explored in human intervention studies.

Probiotic lactobacilli attenuate oxysterols-induced alteration of intestinal epithelial cell monolayer permeability: Focus on tight junction modulation.

Oxidative stress and inflammation lead by dietary oxidised lipids, as oxysterols, have been linked to the loss of intestinal barrier integrity, a crucial event in the initiation and progression of intestinal disorders. In the last decade, probiotic lactobacilli have emerged as an interesting tool to improve intestinal health, thanks to their antioxidant and anti-inflammatory properties. The aim of the present study was to evaluate the ability of two commercial probiotic strains of lactobacilli (Lactiplantibacillus plantarum 299v® (DMS 9843) and Lacticaseibacillus casei DG® (CNCMI-1572)), both as live bacteria and intracellular content, to attenuate the oxysterols-induced alteration of intestinal epithelial Caco-2 cell monolayer permeability. Our investigation was focused on the modulation of tight junctions (TJs) proteins, occludin, ZO-1 and JAM-A, in relation to redox-sensitive MAPK p38 activation. Obtained results provided evidence on the ability of the two probiotics to counteract the alteration of monolayer permeability and loss of TJs proteins, at least in part, through the modulation of p38 pathway. The protective action was exerted by live bacteria, whose adhesion to Caco-2 cells was not altered by oxysterols, and bacterial intracellular components equally able to interact with the signaling pathway.

Wholegrain fermentation affects gut microbiota composition, phenolic acid metabolism and pancreatic beta cell function in a rodent model of type 2 diabetes.

The intestinal microbiota plays an important role in host metabolism via production of dietary metabolites. Microbiota imbalances are linked to type 2 diabetes (T2D), but dietary modification of the microbiota may promote glycemic control. Using a rodent model of T2D and an in vitro gut model system, this study investigated whether differences in gut microbiota between control mice and mice fed a high-fat, high-fructose (HFHFr) diet influenced the production of phenolic acid metabolites following fermentation of wholegrain (WW) and control wheat (CW). In addition, the study assessed whether changes in metabolite profiles affected pancreatic beta cell function. Fecal samples from control or HFHFr-fed mice were fermented in vitro with 0.1% (w/v) WW or CW for 0, 6, and 24 h. Microbiota composition was determined by bacterial 16S rRNA sequencing and phenolic acid (PA) profiles by UPLC-MS/MS. Cell viability, apoptosis and insulin release from pancreatic MIN6 beta cells and primary mouse islets were assessed in response to fermentation supernatants and selected PAs. HFHFr mice exhibited an overall dysbiotic microbiota with an increase in abundance of proteobacterial taxa (particularly Oxalobacteraceae) and Lachnospiraceae, and a decrease in Lactobacillus. A trend toward restoration of diversity and compositional reorganization was observed following WW fermentation at 6 h, although after 24 h, the HFHFr microbiota was monodominated by Cupriavidus. In parallel, the PA profile was significantly altered in the HFHFr group compared to controls with decreased levels of 3-OH-benzoic acid, 4-OH-benzoic acid, isoferulic acid and ferulic acid at 6 h of WW fermentation. In pancreatic beta cells, exposure to pre-fermentation supernatants led to inhibition of insulin release, which was reversed over fermentation time. We conclude that HFHFr mice as a model of T2D are characterized by a dysbiotic microbiota, which is modulated by the in vitro fermentation of WW. The differences in microbiota composition have implications for PA profile dynamics and for the secretory capacity of pancreatic beta cells.

Calcium and Iron Content of Cereal-Based Gluten-Free Products.

The impact of a gluten-free (GF) diet on the intake of calcium and iron is broadly unknown, as the micronutrient content of GF cereal-based products has scarcely been measured. The study aimed to measure the calcium and iron content of GF cereal-based products from the UK. Seventy-three GF products were analysed. A laboratory analysis of calcium and iron from GF food samples was performed by spectrophotometric and flame emission photometry, respectively. The values for wheat-based products were from a nutrient database. The calcium in GF white loaf samples varied greatly from 54 to 140 mg/100 g, with a lower average calcium content compared with wheat-based values (99 ± 29 mg/100 g n = 13 versus 177 mg/100 g; p < 0.01). Only 27% of the white loaves and rolls were fortified with calcium; this contrasts with 100% of white wheat-based loaves. The calcium in GF flour mixes ranged from 54 to 414 mg/100 g, with 66% fortified. GF white pasta had more calcium compared with wheat-based pasta (76 ± 27 mg/100 g n = 7 versus 24 mg/100 g; p = 0.002). The iron in GF bread loaves and pasta samples was similar to wheat-based comparators, whereas lower iron levels were observed in GF wraps (0.8 ± 0.2 n = 11 versus 1.6 mg/100 g). GF bread had a significantly higher fibre content, and the majority of GF bread had a lower protein content, compared with wheat-based bread products. These calcium and iron values provide a valuable addition towards enabling more accurate nutrient intake analysis for adults and children with coeliac disease.

An In Vitro Pilot Fermentation Study on the Impact of Chlorella pyrenoidosa on Gut Microbiome Composition and Metabolites in Healthy and Coeliac Subjects.

The response of a coeliac and a healthy gut microbiota to the green algae Chlorella pyrenoidosa was evaluated using an in vitro continuous, pH controlled, gut model system, which simulated the human colon. The effect of C. pyrenoidosa on the microbial structure was determined by 16S rRNA gene sequencing and inferred metagenomics, whereas the metabolic activitywas determined by1H-nuclear magnetic resonancespectroscopic analysis. The addition of C. pyrenoidosa significantly increased the abundance of the genera Prevotella, Ruminococcus and Faecalibacterium in the healthy donor, while an increase in Faecalibacterium, Bifidobacterium and Megasphaera and a decrease in Enterobacteriaceae were observed in the coeliac donor. C. pyrenoidosa also altered several microbial pathways including those involved in short-chain fatty acid (SCFA) production. At the metabolic level, a significant increase from baseline was seen in butyrate and propionate (p < 0.0001) in the healthy donor, especially in vessels 2 and 3. While acetate was significantly higher in the healthy donor at baseline in vessel 3 (p < 0.001) compared to the coeliac donor, this was markedly decreased after in vitro fermentation with C. pyrenoidosa. This is the first in vitro fermentation study of C. pyrenoidosa and human gut microbiota, however, further in vivo studies are needed to prove its efficacy.

Clinical Efficacy of Brown Seaweeds Ascophyllum nodosum and Fucus vesiculosus in the Prevention or Delay Progression of the Metabolic Syndrome: A Review of Clinical Trials.

Metabolic syndrome (MetS) is a global public health problem affecting nearly 25.9% of the world population characterised by a cluster of disorders dominated by abdominal obesity, high blood pressure, high fasting plasma glucose, hypertriacylglycerolaemia and low HDL-cholesterol. In recent years, marine organisms, especially seaweeds, have been highlighted as potential natural sources of bioactive compounds and useful metabolites, with many biological and physiological activities to be used in functional foods or in human nutraceuticals for the management of MetS and related disorders. Of the three groups of seaweeds, brown seaweeds are known to contain more bioactive components than either red and green seaweeds. Among the different brown seaweed species, Ascophyllum nodosum and Fucus vesiculosus have the highest antioxidant values and highest total phenolic content. However, the evidence base relies mainly on cell line and small animal models, with few studies to date involving humans. This review intends to provide an overview of the potential of brown seaweed extracts Ascophyllum nodosum and Fucus vesiculosus for the management and prevention of MetS and related conditions, based on the available evidence obtained from clinical trials.

Comparative Evaluation of the Antimicrobial and Mucus Induction Properties of Selected Bacillus Strains against Enterotoxigenic Escherichia coli.

Probiotics have been shown to bind to host receptors, which are important for pathogen adhesion and induce the host's production of defence factors. They can activate the goblet-cell-derived production of mucins, a major component of the mucus layer and a physical barrier participating in limiting the proximity of microorganisms to the epithelial layer. In the last decade, Bacillus spp. strains have gained interest in human and animal health due to their tolerance and stability under gastrointestinal tract conditions. Moreover, Bacillus spp. strains can also produce various antimicrobial peptides that can support their use as commercial probiotic supplements and functional foods. The present study aimed to evaluate and determine the ability of selected Bacillus spp. strains to inhibit the growth of enterotoxigenic Escherichia coli (ETEC) F4 and to reduce binding of ETEC F4 to HT29-16E (mucus-secreting and goblet-like) human intestinal cells. Moreover, mucus production in the HT29 cells in the presence of the Bacillus spp. strains was quantified by ELISA. Bacillus spp. strains (CHCC 15076, CHCC 15516, CHCC 15541, and CHCC 16872) significantly inhibited the growth of ETEC F4. Moreover, the ability of the probiotic Bacillus spp. strains to stimulate mucin release was highly strain dependent. The treatment with Bacillus subtilis CHCC 15541 resulted in a significant increase of both MUC2 and MUC3 in HT29-16E cells. Therefore, this strain could be an up-and-coming candidate for developing commercial probiotic supplements to prevent infections caused by ETEC F4 and, potentially, other pathogens.

Chronic social stress in mice alters energy status including higher glucose need but lower brain utilization.

Chronic stress leads to changes in energy status and is a major risk factor for depression, with common symptoms of reductions in body weight and effortful motivation for reward. Indeed, stress-induced disturbed energy status could be a major aetio-pathogenic factor for depression. Improved understanding of these putative inter-relationships requires animal model studies of effects of stress on both peripheral and central energy-status measures and determinants. Here we conducted a study in mice fed on a standard low-fat diet and exposed to either 15-day chronic social stress (CSS) or control handling (CON). Relative to CON mice, CSS mice had attenuated body weight maintenance/gain despite consuming the same amount of food and expending the same amount of energy at any given body weight. The low weight of CSS mice was associated with less white and brown adipose tissues, and with a high respiratory exchange ratio consistent with increased dependence on glucose as energy substrate. Basal plasma insulin was low in CSS mice and exogenous glucose challenge resulted in a relatively prolonged elevation of blood glucose. With regard to hunger and satiety hormones, respectively, CSS mice had higher levels of acylated ghrelin in plasma and of ghrelin receptor gene expression in ventromedial hypothalamus and lower levels of plasma leptin, relative to CON mice. However, whilst CSS mice displayed this constellation of peripheral changes consistent with increases in energy need and glucose utilization relative to CON mice, they also displayed attenuated uptake of [18F]FDG in brain tissue specifically. Reduced brain glucose utilization in CSS mice could contribute to the reduced effortful motivation for reward in the form of sweet-tasting food that we have reported previously for CSS mice. It will now be important to utilize this model to further understanding of the mechanisms via which chronic stress can increase energy need but decrease brain glucose utilization and how this relates to regional and cellular changes in neural circuits for reward processing relevant to depression.

Impact of lignans in oilseed mix on gut microbiome composition and enterolignan production in younger healthy and premenopausal women: an in vitro pilot study.

BACKGROUND: Dietary lignans belong to the group of phytoestrogens together with coumestans, stilbenes and isoflavones, and themselves do not exhibit oestrogen-like properties. Nonetheless, the gut microbiota converts them into enterolignans, which show chemical similarity to the human oestrogen molecule. One of the richest dietary sources of lignans are oilseeds, including flaxseed. The aim of this pilot study was to determine the concentration of the main dietary lignans in an oilseed mix, and explore the gut microbiota-dependent production of enterolignans for oestrogen substitution in young and premenopausal women. The oilseed mix was fermented in a pH-controlled batch culture system inoculated with women's faecal samples. The lignan content and enterolignan production were measured by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), and the faecal-derived microbial communities were profiled by 16S rRNA gene-based next-generation sequencing. RESULTS: In vitro batch culture fermentation of faecal samples inoculated with oilseed mix for 24 h resulted in a substantial increase in enterolactone production in younger women and an increase in enterodiol in the premenopausal group. As for the gut microbiota, different baseline profiles were observed as well as different temporal dynamics, mainly related to Clostridiaceae, and Klebsiella and Collinsella spp. CONCLUSIONS: Despite the small sample size, our pilot study revealed that lignan-rich oilseeds could strongly influence the faecal microbiota of both younger and premenopausal females, leading to a different enterolignan profile being produced. Further studies in larger cohorts are needed to evaluate the long-term effects of lignan-rich diets on the gut microbiota and find out how enterolactone-producing bacterial species could be increased. Diets rich in lignans could potentially serve as a safe supplement of oestrogen analogues to meet the cellular needs of endogenous oestrogen and deliver numerous health benefits, provided that the premenopausal woman microbiota is capable of converting dietary precursors into enterolignans.

Effects of aronia berry (poly)phenols on vascular function and gut microbiota: a double-blind randomized controlled trial in adult men.

BACKGROUND: Aronia melanocarpa is a rich source of (poly)phenols. Previous research has demonstrated that these berries may provide cardiovascular health benefits in high-risk populations. However, very few studies have investigated the effects of daily consumption of dietary achievable amounts of the berries in healthy subjects. OBJECTIVES: The aim of this study was to investigate the effects of aronia berries on vascular function and gut microbiota composition in a healthy population. METHODS: A double-blind, placebo-controlled, parallel designed study was conducted in 66 healthy men randomly allocated to consume a (poly)phenol-rich extract (116 mg, 75 g berries), a whole fruit powder (12 mg, 10 g berries), or placebo (maltodextrin) for 12 wk. Flow-mediated dilation (FMD), arterial stiffness, blood pressure, heart rate, and serum biochemistry were assessed. Plasma (poly)phenol metabolites were analyzed by LC-MS. Gut microbiota composition was determined via 16S rRNA sequencing in stool samples. RESULTS: Consumption of aronia whole fruit and extract powder for 12 wk led to a significant increase in FMD over control of 0.9% ± 0.4% (95% CI: 0.13%, 1.72%) and 1.2% ± 0.4% (95% CI: 0.36%, 1.97%), respectively. Acute improvements in FMD were also observed 2 h after consumption of aronia extract on day 1 (1.1% ± 0.3%, P = 0.003) and 12 wk later (1.5% ± 0.4%, P = 0.0001). Circulating plasma phenolic metabolites increased upon consumption of the aronia treatments. Although no changes were found in gut microbiota diversity, consumption of aronia extract increased the growth of Anaerostipes (+10.6%, P = 0.01), whereas aronia whole fruit showed significant increases in Bacteroides (+193%, P = 0.01). Correlation analysis identified significant associations between changes in FMD, aronia-derived phenolic metabolites, and specific gut microbial genera. CONCLUSIONS: In healthy men, consumption of aronia berry (poly)phenols improved endothelial function and modulated gut microbiota composition, indicating that regular aronia consumption has the potential to maintain cardiovascular health in individuals at low risk of cardiovascular disease. This trial was registered at CLINICALTRIALs.gov as NCT03041961.

Prebiotic Supplementation of In Vitro Fecal Fermentations Inhibits Proteolysis by Gut Bacteria, and Host Diet Shapes Gut Bacterial Metabolism and Response to Intervention.

Metabolism of protein by gut bacteria is potentially detrimental due to the production of toxic metabolites, such as ammonia, amines, p-cresol, and indole. The consumption of prebiotic carbohydrates results in specific changes in the composition and/or activity of the microbiota that may confer benefits to host well-being and health. Here, we have studied the impact of prebiotics on proteolysis within the gut in vitro Anaerobic stirred batch cultures were inoculated with feces from omnivores (n = 3) and vegetarians (n = 3) and four protein sources (casein, meat, mycoprotein, and soy protein) with and without supplementation by an oligofructose-enriched inulin. Bacterial counts and concentrations of short-chain fatty acids (SCFA), ammonia, phenol, indole, and p-cresol were monitored during fermentation. Addition of the fructan prebiotic Synergy1 increased levels of bifidobacteria (P = 0.000019 and 0.000013 for omnivores and vegetarians, respectively). Branched-chain fatty acids (BCFA) were significantly lower in fermenters with vegetarians' feces (P = 0.004), reduced further by prebiotic treatment. Ammonia production was lower with Synergy1. Bacterial adaptation to different dietary protein sources was observed through different patterns of ammonia production between vegetarians and omnivores. In volunteer samples with high baseline levels of phenol, indole, p-cresol, and skatole, Synergy1 fermentation led to a reduction of these compounds.IMPORTANCE Dietary protein intake is high in Western populations, which could result in potentially harmful metabolites in the gut from proteolysis. In an in vitro fermentation model, the addition of prebiotics reduced the negative consequences of high protein levels. Supplementation with a prebiotic resulted in a reduction of proteolytic metabolites in the model. A difference was seen in protein fermentation between omnivore and vegetarian gut microbiotas: bacteria from vegetarian donors grew more on soy and Quorn than on meat and casein, with reduced ammonia production. Bacteria from vegetarian donors produced less branched-chain fatty acids (BCFA).

Fecal microbiota and bile acid interactions with systemic and adipose tissue metabolism in diet-induced weight loss of obese postmenopausal women.

BACKGROUND: Microbiota and bile acids in the gastrointestinal tract profoundly alter systemic metabolic processes. In obese subjects, gradual weight loss ameliorates adipose tissue inflammation and related systemic changes. We assessed how rapid weight loss due to a very low calorie diet (VLCD) affects the fecal microbiome and fecal bile acid composition, and their interactions with the plasma metabolome and subcutaneous adipose tissue inflammation in obesity. METHODS: We performed a prospective cohort study of VLCD-induced weight loss of 10% in ten grades 2-3 obese postmenopausal women in a metabolic unit. Baseline and post weight loss evaluation included fasting plasma analyzed by mass spectrometry, adipose tissue transcription by RNA sequencing, stool 16S rRNA sequencing for fecal microbiota, fecal bile acids by mass spectrometry, and urinary metabolic phenotyping by 1H-NMR spectroscopy. Outcome measures included mixed model correlations between changes in fecal microbiota and bile acid composition with changes in plasma metabolite and adipose tissue gene expression pathways. RESULTS: Alterations in the urinary metabolic phenotype following VLCD-induced weight loss were consistent with starvation ketosis, protein sparing, and disruptions to the functional status of the gut microbiota. We show that the core microbiome was preserved during VLCD-induced weight loss, but with changes in several groups of bacterial taxa with functional implications. UniFrac analysis showed overall parallel shifts in community structure, corresponding to reduced abundance of the genus Roseburia and increased Christensenellaceae;g__ (unknown genus). Imputed microbial functions showed changes in fat and carbohydrate metabolism. A significant fall in fecal total bile acid concentration and reduced deconjugation and 7-α-dihydroxylation were accompanied by significant changes in several bacterial taxa. Individual bile acids in feces correlated with amino acid, purine, and lipid metabolic pathways in plasma. Furthermore, several fecal bile acids and bacterial species correlated with altered gene expression pathways in adipose tissue. CONCLUSIONS: VLCD dietary intervention in obese women changed the composition of several fecal microbial populations while preserving the core fecal microbiome. Changes in individual microbial taxa and their functions correlated with variations in the plasma metabolome, fecal bile acid composition, and adipose tissue transcriptome. Trial Registration ClinicalTrials.gov NCT01699906, 4-Oct-2012, Retrospectively registered. URL- https://clinicaltrials.gov/ct2/show/NCT01699906.

A prebiotic intervention study in children with autism spectrum disorders (ASDs).

BACKGROUND: Different dietary approaches, such as gluten and casein free diets, or the use of probiotics and prebiotics have been suggested in autistic spectrum disorders in order to reduce gastrointestinal (GI) disturbances. GI symptoms are of particular interest in this population due to prevalence and correlation with the severity of behavioural traits. Nowadays, there is lack of strong evidence about the effect of dietary interventions on these problems, particularly prebiotics. Therefore, we assessed the impact of exclusion diets and a 6-week Bimuno® galactooligosaccharide (B-GOS®) prebiotic intervention in 30 autistic children. RESULTS: The results showed that children on exclusion diets reported significantly lower scores of abdominal pain and bowel movement, as well as lower abundance of Bifidobacterium spp. and Veillonellaceae family, but higher presence of Faecalibacterium prausnitzii and Bacteroides spp. In addition, significant correlations were found between bacterial populations and faecal amino acids in this group, compared to children following an unrestricted diet. Following B-GOS® intervention, we observed improvements in anti-social behaviour, significant increase of Lachnospiraceae family, and significant changes in faecal and urine metabolites. CONCLUSIONS: To our knowledge, this is the first study where the effect of exclusion diets and prebiotics has been evaluated in autism, showing potential beneficial effects. A combined dietary approach resulted in significant changes in gut microbiota composition and metabolism suggesting that multiple interventions might be more relevant for the improvement of these aspects as well as psychological traits. TRIAL REGISTRATION: NCT02720900 ; registered in November 2015.

Preventive Effect of a Synbiotic Combination of Galacto- and Fructooligosaccharides Mixture With Bifidobacterium breve M-16V in a Model of Multiple Rotavirus Infections.

Rotavirus (RV) causes morbidity and mortality among infants worldwide, and there is evidence that probiotics and prebiotics can have a positive influence against infective processes such as that due to RV. The aim of this study was to evidence a preventive role of one prebiotic mixture (of short-chain galactooligosaccharide/long-chain fructooligosaccharide), the probiotic Bifidobacterium breve M-16V and the combination of the prebiotic and the probiotic, as a synbiotic, in a suckling rat double-RV infection model. Hyperimmune bovine colostrum was used as protection control. The first infection was induced with RV SA11 and the second one with EDIM. Clinical variables and immune response were evaluated after both infections. Dietary interventions ameliorated clinical symptoms after the first infection. The prebiotic and the synbiotic significantly reduced viral shedding after the first infection, but all the interventions showed higher viral load than in the RV group after the second infection. All interventions modulated ex vivo antibody and cytokine production, gut wash cytokine levels and small intestine gene expression after both infections. In conclusion, a daily supplement of the products tested in this preclinical model is highly effective in preventing RV-induced diarrhea but allowing the boost of the early immune response for a future immune response against reinfection, suggesting that these components may be potential agents for modulating RV infection in infants.