Propionate and butyrate counteract renal damage and progression to chronic kidney disease.

BACKGROUND: Short-chain fatty acids (SCFAs), mainly acetate, propionate and butyrate, are produced by gut microbiota through fermentation of complex carbohydrates that cannot be digested by the human host. They affect gut health and can contribute at the distal level to the pathophysiology of several diseases, including renal pathologies. METHODS: SCFA levels were measured in chronic kidney disease (CKD) patients (n = 54) at different stages of the disease and associations with renal function and inflammation parameters were examined. The impact of propionate and butyrate in pathways triggered in tubular cells under inflammatory conditions was analysed using genome-wide expression assays. Finally, a pre-clinical mouse model of folic acid-induced transition from acute kidney injury to CKD was used to analyse the preventive and therapeutic potential of these microbial metabolites in the development of CKD. RESULTS: Faecal levels of propionate and butyrate in CKD patients gradually reduce as the disease progresses, and do so in close association with established clinical parameters for serum creatinine, blood urea nitrogen and the estimated glomerular filtration rate. Propionate and butyrate jointly downregulated the expression of 103 genes related to inflammatory processes and immune system activation triggered by TNF-α in tubular cells. In vivo, the administration of propionate and butyrate, either before or soon after injury, respectively prevented and slowed the progression of damage. This was indicated by a decrease in renal injury markers, the expression of pro-inflammatory and pro-fibrotic markers, and recovery of renal function over the long term. CONCLUSIONS: Propionate and butyrate levels are associated with a progressive loss of renal function in CKD patients. Early administration of these SCFAs prevents disease advancement in a pre-clinical model of acute renal damage, demonstrating their therapeutic potential independently of the gut microbiota.

Human fecal alpha-glucosidase activity and its relationship with gut microbiota profiles and early stages of intestinal mucosa damage.

OBJECTIVES: We investigated potential relationships among initial lesions of the intestinal mucosa, fecal enzymatic activities and microbiota profiles. METHODS: Fecal samples from 54 volunteers were collected after recruitment among individuals participating in a colorectal cancer (CRC) screening program in our region (Northern Spain) or attending for consultation due to clinical symptoms; intestinal mucosa samples were resected during colonoscopy. Enzymatic activities were determined in fecal supernatants by a semi-quantitative method. The fecal microbiota composition was determined by 16S rRNA gene-based sequencing. The results were compared between samples from clinical diagnosis groups (controls and polyps), according with the type of polyp (hyperplastic polyps or conventional adenomas) and considering the grade of dysplasia for conventional adenomas (low and high grade dysplasia). RESULTS: High levels of α-glucosidase activity were more frequent among samples from individuals diagnosed with intestinal polyps, reaching statistical significance for conventional adenomas and for low grade dysplasia adenomas when compared to controls. Regarding the microbiota profiles, higher abundance of Christensenellaceae_R-7 group and Oscillospiraceae_UCG-002 were found in fecal samples displaying low α-glucosidase activity as compared with those with higher activity as well as in controls with respect to conventional adenomas. A relationship was evidenced among intestinal mucosal lesions, gut glucosidase activities and intestinal microbiota profiles. CONCLUSIONS: Our findings suggest a relationship among altered fecal α-glucosidase levels, the presence of intestinal mucosal lesions, which can be precursors of CRC, and shifts in defined microbial groups of the fecal microbiota.

Role of the intestinal microbiota and diet in the onset and progression of colorectal and breast cancers and the interconnection between both types of tumours.

Colorectal cancer (CRC) is among the leading causes of mortality in adults of both sexes worldwide, while breast cancer (BC) is among the leading causes of death in women. In addition to age, gender, and genetic predisposition, environmental and lifestyle factors exert a strong influence. Global diet, including alcohol consumption, is one of the most important modifiable factors affecting the risk of CRC and BC. Western dietary patterns promoting high intakes of xenobiotics from food processing and ethanol have been associated with increased cancer risk, whereas the Mediterranean diet, generally leading to a higher intake of polyphenols and fibre, has been associated with a protective effect. Gut dysbiosis is a common feature in CRC, where the usual microbiota is progressively replaced by opportunistic pathogens and the gut metabolome is altered. The relationship between microbiota and BC has been less studied. The estrobolome is the collection of genes from intestinal bacteria that can metabolize oestrogens. In a dysbiosis condition, microbial deconjugating enzymes can reactivate conjugated-deactivated oestrogens, increasing the risk of BC. In contrast, intestinal microorganisms can increase the biological activity and bioavailability of dietary phytochemicals through diverse microbial metabolic transformations, potentiating their anticancer activity. Members of the intestinal microbiota can increase the toxicity of xenobiotics through metabolic transformations. However, most of the microorganisms involved in diet-microbiota interactions remain poorly characterized. Here, we provide an overview of the associations between microbiota and diet in BC and CRC, considering the diverse types and heterogeneity of these cancers and their relationship between them and with gut microbiota.

Probiotic-Induced Modulation of Microbiota Composition and Antibiotic Resistance Genes Load, an In Vitro Assessment.

The imbalance of the gut microbiota (GM) is known as dysbiosis and is associated with disorders such as obesity. The increasing prevalence of microorganisms harboring antibiotic resistance genes (ARG) in the GM has been reported as a potential risk for spreading multi-drug-resistant pathogens. The objective of this work was the evaluation, in a fecal culture model, of different probiotics for their ability to modulate GM composition and ARG levels on two population groups, extremely obese (OB) and normal-weight (NW) subjects. Clear differences in the basal microbiota composition were observed between NW and OB donors. The microbial profile assessed by metataxonomics revealed the broader impact of probiotics on the OB microbiota composition. Also, supplementation with probiotics promoted significant reductions in the absolute levels of tetM and tetO genes. Regarding the blaTEM gene, a minor but significant decrease in both donor groups was detected after probiotic addition. A negative association between the abundance of Bifidobacteriaceae and the tetM gene was observed. Our results show the ability of some of the tested strains to modulate GM. Moreover, the results suggest the potential application of probiotics for reducing the levels of ARG, which constitutes an interesting target for the future development of probiotics.

Associations of dietary factors and xenobiotic intake with faecal microbiota composition according to the presence of intestinal mucosa damage.

Diet is a major modulator of gut microbiota, which plays a key role in the health status, including colorectal cancer (CRC) development. Several studies and meta-analyses have evidenced an association of certain dietary factors and xenobiotic intake with the incidence of CRC. Nevertheless, how these dietary factors impact the first stages of intestinal mucosa damage is still uncertain. This study aimed at exploring the associations of relevant dietary factors with the gut microbiota of control individuals and subjects diagnosed with intestinal polyps. A total of 60 volunteers were recruited, clinically classified according to colonoscopy criteria and interviewed using food frequency questionnaires (FFQs). The nutritional status of each volunteer was determined and the intake of dietary xenobiotics was quantified. The relative abundance of faecal microbiota taxonomic groups was obtained through 16S rRNA gene sequencing. The association of dietary factors and xenobiotics with faecal microbiota composition showed differences according to the clinical diagnosis group. Our results showed that the intake of red meat (≥50 g day-1) and total polycyclic aromatic hydrocarbons (PAHs) (≥0.75 µg day-1) was associated with a decreased abundance of the family Bacteroidaceae and an increased abundance of Coriobacteriaceae in control subjects. The intake of the heterocyclic amines 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) (≥40 ng day-1) and 2-amino-3,8 dimethylimidazo(4,5,f) quinoxaline (MeIQx) (≥50 ng day-1) was associated with a decreased abundance of Akkermansiaceae in the control diagnosis group. Moreover, N-nitroso compounds (NOCs), nitrites (≥1.69 mg day-1) and N-nitrosodimethylamine (NDMA) (≥0.126 µg day-1) were associated with a decreased abundance of Bifidobacteriaceae. The intake of ethanol (≥12 g day-1) in the polyps group was associated with an increased abundance of Peptostreptococcaceae and a decreased abundance of Veillonellaceae. Moreover, linear regression analyses allowed us to identify ethanol, calcium, bioactive compounds such as flavonoids, stilbenes, cellulose, phenolic acids or total polyphenols, and dietary xenobiotics such as PhIP and MeIQx, the NOC N-nitrosopyrrolidine (NPYR) or the total PAHs as potential predictors of faecal microbiota group abundances. These results indicated that the consumption of milk, red meat, processed meat and ethanol and the intake of polyphenols, dietary PAHs, HAs and NOCs are associated with specific groups of the intestinal microbiota, depending on the clinical diagnosis group.

Impact on Fecal Microbiota and Health-Related Markers of an Intervention Focused on Improving Eating Behavior in People at Risk of Food Insecurity.

Non-communicable diseases are particularly prevalent among low-income individuals and are associated with the consumption of processed foods, fat, and sugars. This work aims to evaluate the impacts of a nutrition education intervention for low socio-economic individuals on sensory perception, health-related parameters and gut microbiota. Twenty low-income adults underwent a 4-week intervention. Dietary information (three 24 h recalls), detection thresholds and discrimination scores (salty and sweet), and severity of depressive symptoms (Beck Depression Inventory-II (BDI-II)) were collected. Fecal microbial composition and short chain fatty acids were determined by 16S ribosomal RNA-gene sequencing and gas chromatography, respectively. After the intervention, 35% of subjects presented higher compliance with dietary recommendations, increased consumption of vegetables and lignans and reduced consumption of processed meats and nitrosamines, together with depleted levels of Actinomycetota. Higher discrimination for salty and sweet and lower BDI-II scores were also obtained. This nutrition education intervention entailed changes in dietary intake towards healthier food options, reduced potentially carcinogenic compounds and improved scores for discrimination and severity of depressive symptoms. The confirmation of these results in future studies would enable the design of strategic policies contributing to the optimal nutrition of materially deprived families through affordable healthy plant-based interventions.

An Overview on Fecal Profiles of Amino Acids and Related Amino-Derived Compounds in Children with Autism Spectrum Disorder in Tunisia.

Autism spectrum disorder (ASD) is a neurodevelopmental pathology characterized by the impairment of social interaction, difficulties in communication, and repetitive behaviors. Alterations in the metabolism of amino acids have been reported. We performed a chromatographic analysis of fecal amino acids, ammonium, biogenic amines, and gamma aminobutyric acid (GABA) in Tunisian autistic children from 4 to 10 years, and results were compared with their siblings (SIB) and children from the general population (GP). ASD presented significantly higher levels of fecal amino acids than SIB and GP; differences being more pronounced in younger (4-7 years) than in older (8-10 years) individuals whereas no changes were found for the remaining compounds. Lower levels of histidine were the only difference related with severe symptoms of autism (CARS scale). A linear discriminant analysis (LDA) based on fecal amino acid profiles clearly separated ASD, SIB, and GP at 4 to 7 years but not at more advanced age (8-10 years), evidencing more pronounced alterations in younger children. The relationship of fecal amino acids with autism needs deeper research integrating blood analytical parameters, brain metabolism, and intestinal microbiota. Fecal amino acids could be targeted for designing personalized diets to prevent or minimize cognitive impairments associated with ASD.

Commensal Fecal Microbiota Profiles Associated with Initial Stages of Intestinal Mucosa Damage: A Pilot Study.

Progressive intestinal mucosal damage occurs over years prior to colorectal cancer (CRC) development. The endoscopic screening of polyps and histopathological examination are used clinically to determine the risk and progression of mucosal lesions. We analyzed fecal microbiota compositions using 16S rRNA gene-based metataxonomic analyses and the levels of short-chain fatty acids (SCFAs) using gas chromatography in volunteers undergoing colonoscopy and histopathological analyses to determine the microbiota shifts occurring at the early stages of intestinal mucosa alterations. The results were compared between diagnosis groups (nonpathological controls and polyps), between samples from individuals with hyperplastic polyps or conventional adenomas, and between grades of dysplasia in conventional adenomas. Some microbial taxa from the Bacillota and Euryarchaeota phyla were the most affected when comparing the diagnosis and histopathological groups. Deeper microbiota alterations were found in the conventional adenomas than in the hyperplastic polyps. The Ruminococcus torques group was enriched in both the hyperplastic polyps and conventional adenomas, whereas the family Eggerthellaceae was enriched only in the hyperplastic polyps. The abundance of Prevotellaceae, Oscillospiraceae, Methanobacteriaceae, Streptococcaceae, Christensenellaceae, Erysipelotrichaceae, and Clostridiaceae shifted in conventional adenomas depending on the grade of dysplasia, without affecting the major SCFAs. Our results suggest a reorganization of microbial consortia involved in gut fermentative processes.

Dietary xenobiotics, (poly)phenols and fibers: Exploring associations with gut microbiota in socially vulnerable individuals.

Objectives: Although xenobiotics derived from food processing may cause modifications in the composition of the gut microbiota (GM) evidence is scarce. The aim of this study is to evaluate the impact of potential dietary carcinogens as heterocyclic amines (HAs), polycyclic aromatic hydrocarbons (PAHs), nitrates, nitrites, nitroso compounds and acrylamide, in combination to fibers (poly)phenols on the GM composition in a group of materially deprived subjects. Study design: Transversal observational study in a sample of 19 subjects recipients of Red Cross food aid. Dietary information was recorded by means of 3 non-consecutive 24 h recalls. Questions focused on the type of cooking and the extent of cooking and roasting were included. Information on potential carcinogens was mainly obtained from the European Prospective Investigation into Cancer and Nutrition (EPIC) and Computerized Heterocyclic Amines Resource for Research in Epidemiology of Disease (CHARRED) Carcinogen Databases. Microbial composition was determined by 16S ribosomal RNA gene sequencing in fecal samples. Results: Higher levels of Lachnospiraceae and Eggerthellaceae families were found in individuals consuming less than 50 ng/day of 2-amino-3,8 dimethylimidazo (4,5,f) quinoxaline (MeIQx) (considered as lower risk dose for colorectal adenoma) while those consuming more than 40 ng/day of 2-amino-1-methyl-6-phenylimidazo (4,5,b) pyridine (PhIP) (higher risk for colorectal adenoma) showed lower relative abundance of Muribaculaceae and greater presence of Streptococcaceae and Eubacterium coprostanoligenes group. Conclusion: The associations identified between diet and processing by-products on GM in this study could be used as potential targets for the designing of dietary interventions tailored to this collective.

Diet and Microbiome in Health and Aging.

After several years of research, sufficient evidence has been found supporting that diet is one of the main factors able to modulate both composition and activity of the intestinal microbiota, thus positioning it as a cornerstone in the host-microbiota interface [...].

Fecal Metabolome and Bacterial Composition in Severe Obesity: Impact of Diet and Bariatric Surgery.

The aim of this study was to monitor the impact of a preoperative low-calorie diet and bariatric surgery on the bacterial gut microbiota composition and functionality in severe obesity and to compare sleeve gastrectomy (SG) versus Roux-en-Y gastric bypass (RYGB). The study also aimed to incorporate big data analysis for the omics results and machine learning by a Lasso-based analysis to detect the potential markers for excess weight loss. Forty patients who underwent bariatric surgery were recruited (14 underwent SG, and 26 underwent RYGB). Each participant contributed 4 fecal samples (baseline, post-diet, 1 month after surgery and 3 months after surgery). The bacterial composition was determined by 16S rDNA massive sequencing using MiSeq (Illumina). Metabolic signatures associated to fecal concentrations of short-chain fatty acids, amino acids, biogenic amines, gamma-aminobutyric acid and ammonium were determined by gas and liquid chromatography. Orange 3 software was employed to correlate the variables, and a Lasso analysis was employed to predict the weight loss at the baseline samples. A correlation between Bacillota (formerly Firmicutes) abundance and excess weight was observed only for the highest body mass indexes. The low-calorie diet had little impact on composition and targeted metabolic activity. RYGB had a deeper impact on bacterial composition and putrefactive metabolism than SG, although the excess weight loss was comparable in the two groups. Significantly higher ammonium concentrations were detected in the feces of the RYGB group. We detected individual signatures of composition and functionality, rather than a gut microbiota characteristic of severe obesity, with opposing tendencies for almost all measured variables in the two surgical approaches. The gut microbiota of the baseline samples was not useful for predicting excess weight loss after the bariatric process.

In Vitro Probiotic Modulation of the Intestinal Microbiota and 2'Fucosyllactose Consumption in Fecal Cultures from Infants at Two Months of Age.

2'-fucosyllactose (2'FL) is one of the most abundant oligosaccharides in human milk, with benefits on neonatal health. Previous results point to the inability of the fecal microbiota from some infants to ferment 2'FL. We evaluated a probiotic formulation, including the strains Lactobacillus helveticus Rosell®-52 (R0052), Bifidobacterium longum subsp. infantis Rosell®-33 (R0033), and Bifidobacterium bifidum Rosell®-71 (R0071), individually or in an 80:10:10 combination on the microbiota and 2'FL degradation. Independent batch fermentations were performed with feces from six full-term infant donors of two months of age (three breastfed and three formula-fed) with added probiotic formulation or the constituent strains in the presence of 2'FL. Microbiota composition was analyzed by 16S rRNA gene sequencing. Gas accumulation, pH decrease and 2'FL consumption, and levels of different metabolites were determined by chromatography. B. bifidum R0071 was the sole microorganism promoting a partial increase of 2'FL degradation during fermentation in fecal cultures of 2'FL slow-degrading donors. However, major changes in microbiota composition and metabolic activity occurred with L. helveticus R0052 or the probiotic formulation in cultures of slow degraders. Further studies are needed to decipher the role of the host intestinal microbiota in the efficacy of these strains.

Daily ingestion of Akkermansia mucciniphila for one month promotes healthy aging and increases lifespan in old female mice.

The ingestion of certain probiotics has been suggested as a promising nutritional strategy to improve aging. The objective of this work was to evaluate the effects of the daily intake, for a month, of a new probiotic Akkermansia muciniphila (AKK) (2 × 108 cfu/100µL PBS) on behavior, as well as function and redox state of immune cells of old female ICR-CD1 mice (OA group). For this, several behavioral tests were performed, and function and oxidative-inflammatory stress parameters of peritoneal leukocytes were analyzed in OA group, in a group of the same age that did not take AKK (old control, OC group) and in another adult control (AC) group. The results showed, in OA group, a significant improvement of several behavioral responses (coordination, balance, neuromuscular vigor, exploratory ability and anxiety like-behaviors), as well as in immune functions (chemotaxis, phagocytosis, NK activity and lymphoproliferation) and in oxidative stress parameters (glutathione peroxidase and reductase activities, oxidized glutathione and lipid oxidation concentrations) of the peritoneal leukocytes in comparison to those observed in OC group. In addition, peritoneal immune cells from the OA group released lower basal concentrations of pro-inflammatory cytokines (IL-2, IL-6 and TNF-α) compared to those from the OC group. The values of parameters in OA were similar to those in AC group. These improvements in the old mice receiving the probiotic were reflected in an increase in their lifespan. In conclusion, our data indicate that AKK supplementation for a short period could be a good nutritional strategy to promote healthy longevity.

Role of Bifidobacteria on Infant Health.

Bifidobacteria are among the predominant microorganisms during infancy, being a dominant microbial group in the healthy breastfed infant and playing a crucial role in newborns and infant development. Not only the levels of the Bifidobacterium genus but also the profile and quantity of the different bifidobacterial species have been demonstrated to be of relevance to infant health. Although no definitive proof is available on the causal association, reduced levels of bifidobacteria are perhaps the most frequently observed alteration of the intestinal microbiota in infant diseases. Moreover, Bifidobacterium strains have been extensively studied by their probiotic attributes. This review compiles the available information about bifidobacterial composition and function since the beginning of life, describing different perinatal factors affecting them, and their implications on different health alterations in infancy. In addition, this review gathers exhaustive information about pre-clinical and clinical studies with Bifidobacterium strains as probiotics in neonates.

Influence of 2'-Fucosyllactose on the Microbiota Composition and Metabolic Activity of Fecal Cultures from Breastfed and Formula-Fed Infants at Two Months of Age.

Although breast milk is considered the gold standard of nutrition for infant feeding, some circumstances may make breastfeeding difficult. Several commercial milk preparations include synthetic human milk oligosaccharides (HMOs) in their composition. However, the effect of HMOs on the establishment of the intestinal microbiota remains incompletely understood. Independent batch fermentations were performed with feces from six full-term infant donors of two months of age (three breastfed and three formula-fed, exclusively) in the presence of 2'fucosyllactose (2'FL), one of the most abundant HMOs in human milk. Microbiota composition was analyzed by 16S rRNA gene sequencing at baseline and at 24 h of incubation. The 2'FL consumption, gas accumulation, and levels of different metabolites were determined by chromatography. Microbiota profiles at baseline were clearly influenced by the mode of feeding and by the intrinsic ability of microbiotas to degrade 2'FL. The 2'FL degradation rate clustered fecal cultures into slow and fast degraders, regardless of feeding type, this being a determinant factor influencing the evolution of the microbiota during incubation, although the low number of donors precludes drawing sound conclusions. More studies are needed to decipher the extent to which the early intervention with HMOs could influence the microbiota as a function of its ability to utilize 2'FL.

Intestinal microbiota alterations by dietary exposure to chemicals from food cooking and processing. Application of data science for risk prediction.

Diet is one of the main sources of exposure to toxic chemicals with carcinogenic potential, some of which are generated during food processing, depending on the type of food (primarily meat, fish, bread and potatoes), cooking methods and temperature. Although demonstrated in animal models at high doses, an unequivocal link between dietary exposure to these compounds with disease has not been proven in humans. A major difficulty in assessing the actual intake of these toxic compounds is the lack of standardised and harmonised protocols for collecting and analysing dietary information. The intestinal microbiota (IM) has a great influence on health and is altered in some diseases such as colorectal cancer (CRC). Diet influences the composition and activity of the IM, and the net exposure to genotoxicity of potential dietary carcinogens in the gut depends on the interaction among these compounds, IM and diet. This review analyses critically the difficulties and challenges in the study of interactions among these three actors on the onset of CRC. Machine Learning (ML) of data obtained in subclinical and precancerous stages would help to establish risk thresholds for the intake of toxic compounds generated during food processing as related to diet and IM profiles, whereas Semantic Web could improve data accessibility and usability from different studies, as well as helping to elucidate novel interactions among those chemicals, IM and diet.

In vitro Selection of Probiotics for Microbiota Modulation in Normal-Weight and Severely Obese Individuals: Focus on Gas Production and Interaction With Intestinal Epithelial Cells.

The intestinal microbiota plays important roles in the maintenance of health. Strategies aiming at its modulation, such as probiotics, have received a deal of attention. Several strains have been studied in different in vitro models; however, the correlation of results obtained with the in vivo data has been limited. This questions the usefulness of such in vitro selection models, traditionally relying on over-simplified tests, not considering the influence of the accompanying microbiota or focusing on microbiota composition without considering functional traits. Here we assess the potential of six Bifidobacterium, Lactobacillus and Lacticaseibacillus strains in an in vitro model to determine their impact on the microbiota not just in terms of composition but also of functionality. Moreover, we compared the responses obtained in two different population groups: normal-weight and severely obese subjects. Fecal cultures were conducted to evaluate the impact of the strains on specific intestinal microbial groups, on the production of short-chain fatty acids, and on two functional responses: the production of gas and the interaction with human intestinal epithelial cells. The response to the different probiotics differed between both human groups. The addition of the probiotic strains did not induce major changes on the microbiota composition, with significant increases detected almost exclusively for the species added. Higher levels of gas production were observed in cultures from normal-weight subjects than in the obese population, with some strains being able to significantly reduce gas production in the latter group. Moreover, in obese subjects all the Bifidobacterium strains tested and Lacticaseibacillus rhamnosus GG were able to modify the response of the intestinal cells, restoring values similar to those obtained with the microbiotas of normal-weight subjects. Our results underline the need for the screening and selection of probiotics in a target-population specific manner by using appropriate in vitro models before enrolling in clinical intervention trials.

Microneedle systems as medical devices for esthetical treatments: A risk assessment approach.

BACKGROUND: Microneedling devices are being used as a surgical technique without a clear regulatory category. They can become dangerous considering that these kind of devices can easily be bought and used by nonqualified people. AIMS: Our aim has been to demonstrate that microneedling devices used in dermatological surgery are Medical Devices according to the current regulations. PATIENTS/METHODS: After a thorough review in the European Union and USA medical device classification, we consider microneedling systems as Class II (US) or IIa (EU). RESULTS: Therefore, they must follow the regulations established for medical devices. A risk assessment has also been made, in which the technical and scientific deficiencies in their design and manufacturing have been recognized in addition to including compulsory information for the regulatory agencies and most importantly for the final user. CONCLUSION: It can be concluded that microneedling is an interesting tool in dermatology although more information related to its safety needs to be submitted. In addition, its use by nonprofessional people does not guarantee the safety of the user.

New players in the relationship between diet and microbiota: the role of macromolecular antioxidant polyphenols.

PURPOSE: Solid evidence has emerged supporting the role of polyphenols and fibers as gut microbiota modulators. These studies have been limited to the data available in food composition databases, which did not include the food content of non-extractable polyphenols (NEPP). The main objective of this work is to quantify the intake of the different types of dietary polyphenols including NEPP and to evaluate their impact on the composition and activity of the intestinal microbiota. METHODS: Cross-sectional descriptive study conducted on a sample of 147 adults with no declared pathologies. Dietary intake has been registered by a semi-quantitative Food Frequency Questionnaire (FFQ) and transformed into extractable (EPP) and NEPP, and dietary fibers based on available databases. Major phylogenetic types of the intestinal microbiota were determined by qPCR and fecal SCFA quantification was performed by gas chromatography. RESULTS: NEPP account for two-thirds of the total polyphenols intake. A combined analysis by stepwise regression model including all dietary fiber and (poly)phenols has identified hydrolysable (poly)phenol (HPP) intake, as the best predictor of Bacteroides-Prevotella-Porphyromonas group and Bifidobacterium levels in feces. Also, HPPs were positively associated with butyric acid, while insoluble fiber was identified as a predictor of propionic acid in feces. CONCLUSION: The intake of macromolecular (poly)phenols could contribute to modulate the gut microbiota by increasing the levels of certain intestinal microorganisms with proven health benefits.

Effect of inulin-type fructans and galactooligosaccharides on cultures of Lactobacillus strains isolated in Algeria from camel's milk and human colostrum.

Bacteria from the genus Lactobacillus are responsible for spontaneous food fermentations. Some species, such as Lactobacillus casei and Lactobacillus brevis, have the "Qualified Presumption of Safety" status recognized by the European Food Safety Authority. Several of their strains are used as probiotics in foods and sometimes are included in synbiotic combinations together with prebiotics. New microbial strains isolated from different sources represent an opportunity to use them for the production of traditional food products. The capacity of three selected strains (one isolated from Camel's milk and identified by partial 16 S rRNA gene sequencing as L. brevis, and two isolated from human colostrum and identified as L. paracasei/L. casei and L. brevis, respectively) was assessed in vitro for the ability to survive in gastrointestinal conditions (low pH and high bile salts concentrations). We also tested the capacity of growth and the production of organic acids and volatile compounds by high-performance liquid chromatography and gas chromatography, respectively, when these bacteria were incubated anaerobically in the presence of inulin, fructooligosaccharides, or galactooligosaccharides as the main carbon sources. The strains were able to survive in simulated gastrointestinal conditions and to grow in inulin, fructooligosaccharides, and galactooligosaccharides. However, they displayed different profiles of organic acids and volatile compounds, mainly depending on the microbial species and the prebiotic used. The influence that the combined use of strains and different prebiotics could exert on the organic acids and volatiles formed in food and in the gut should be assessed for each synbiotic combination and food product.