Search

[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., This research was funded by Plan Estatal de I + D + I through projects AGL2017-83653-R (AEI/FEDER, UE) and RTI2018-098288-B-I00 (MCIU/AEI/FEDER, UE) and by contracts with Biopolis SL (Valencia, Spain), CAUCE Foundation (Oviedo, Spain) and Alimerka Foundation (Llanera, Spain). NS. is granted by a postdoctoral contract awarded by the Fundación para la Investigación Biosanitaria de Asturias (FINBA).

[Background] The microbial populations of the human intestinal tract and their relationship to specific diseases have been extensively studied during the last decade. However, the characterization of the human bile microbiota as a whole has been hampered by difficulties in accessing biological samples and the lack of adequate methodologies to assess molecular studies. Although a few reports have described the biliary microbiota in some hepatobiliary diseases, the bile microbiota of healthy individuals has not been described. With this in mind, the goal of the present study was to generate fundamental knowledge on the composition and activity of the human bile microbiota, as well as establishing its potential relationship with human bile-related disorders., [Results] Human bile samples from the gallbladder of individuals from a control group, without any record of hepatobiliary disorder, were obtained from liver donors during liver transplantation surgery. A bile DNA extraction method was optimized together with a quantitative PCR (qPCR) assay for determining the bacterial load. This allows the selection of samples to perform functional metagenomic analysis. Bile samples from the gallbladder of individuals suffering from lithiasis were collected during gallbladder resection and the microbial profiles assessed, using a 16S rRNA gene-based sequencing analysis, and compared with those of the control group. Additionally, the metabolic profile of the samples was analyzed by nuclear magnetic resonance (NMR). We detected, for the first time, bacterial communities in gallbladder samples of individuals without any hepatobiliary pathology. In the biliary microecosystem, the main bacterial phyla were represented by Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. Significant differences in the relative abundance of different taxa of both groups were found. Sequences belonging to the family Propionibacteriaceae were more abundant in bile samples from control subjects; meanwhile, in patients with cholelithiasis members of the families Bacteroidaceae, Prevotellaceae, Porphyromonadaceae, and Veillonellaceae were more frequently detected. Furthermore, the metabolomics analysis showed that the two study groups have different metabolic profiles., [Conclusions] Our results indicate that the gallbladder of human individuals, without diagnosed hepatobiliary pathology, harbors a microbial ecosystem that is described for the first time in this study. Its bacterial representatives and metabolites are different from those detected in people suffering from cholelithiasis. In this regard, since liver donors have been subjected to the specific conditions of the hospital’s intensive care unit, including an antibiotic treatment, we must be cautious in stating that their bile samples contain a physiologically normal biliary microbiome. In any case, our results open up new possibilities to discover bacterial functions in a microbial ecosystem that has not previously been explored., The study was supported by MINECO under grant number AGL2013-44761-P. Lorena Ruiz is a postdoctoral researcher supported by the Juan de la Cierva Postdoctoral Trainee Program (IJCI-2015-23196), and Natalia Molinero is the recipient of an FPI Predoctoral Grant (BES-2014-068736).

Despite the existing evidence on the impact of olive oil and red wine on the intestinal microbiota, the effect of the global Mediterranean Diet (MD) has not been sufficiently studied. We explored the association between the adherence to a Mediterranean dietary pattern, and its components, with faecal microbiota in a cohort of adults with non-declared pathology. This transversal study involved 31 adults without a previous diagnosis of cancer, autoimmune or digestive diseases. Based on the data obtained by means of an annual food frequency questionnaire (FFQ), and the information existing in the literature, a Mediterranean Diet Score (MDS) was calculated. Dietary fibre was obtained from Marlett et al. tables and Phenol-Explorer Database was used for phenolic compounds intake. Quantification of microbial groups was performed by Ion Torrent 16S rRNA gene-based analysis and quantification of short-chain fatty acids (SCFAs) was performed using gas chromatography-mass spectrometry (MS). MDS was associated with a higher abundance of Bacteroidetes (p = 0.001), Prevotellacea (p = 0.002) and Prevotella (p = 0.003) and a lower concentration of Firmicutes (p = 0.003) and Lachnospiraceae (p = 0.045). Also, in subjects with MDS ≥ 4, higher concentrations of faecal propionate (p = 0.034) and butyrate (p = 0.018) were detected. These results confirm the complexity of the diet-microbiota interrelationship., Supported by a grant AGL2010-14952 from the Spanish Ministry of Science and Innovation and in part by a grant from the European Regional Development Fund (GRUPIN14-043; to I. Gutiérrez-Díaz). B. Sánchez was recipient of a Ramón y Cajal postdoctoral contract from the Spanish Ministry of Economy and Competitiveness.

Although most of the health effects attributed to polyphenols may be linked to their phenolic-derived metabolites, the role of the intestinal derived-phenolics in human health is still far from being well understood. We determined the profile of fecal phenolic-derived metabolites, microbiota, biomarkers of oxidative stress and inflammation, and daily intake of bioactive compounds in 71 elderly volunteers. Phenylacetic and phenylpropionic acids were the main phenolic metabolites present in feces. From them, phenylacetic acid was related with a more pro-oxidant and immune stimulated status, and both were negatively associated with fecal propionate, whereas phenylpropionic acid was directly related with the fecal concentration of acetate. Moreover, phenylacetic acid was negatively associated with the Bacteroides group and Clostridium cluster XIVa and positively with Lactobacillus. These results provide a rationale to explore the potential of fecal microbial phenolic-derived metabolites as possible biomarkers of health status in future studies focused on the elderly population., This work was funded by the Spanish MINECO (AGL2015–64522-C2-R) and Comunidad de Madrid (ALIBIRD-CM S2013/ABI-2728), the grant GRUPIN 14–043 “Microbiota humana, Alimentación y Salud” from “Plan Regional de Investigación del Principado de Asturias”, and by a grant from Biopolis SL, with the framework of the e-CENIT Project SENIFOOD from the Spanish Ministry of Science and Innovation. N.S. benefits from a Juan de la Cierva postdoctoral Trainee Program of the Spanish Ministry of Economy and Competitiveness (MINECO).

Recent dietary habits and lifestyle could explain the shaping of the gut microbiota composition and, in consequence, the increasing prevalence of certain pathologies. However, little attention has been paid to the influence of diet on microbiotas, other than the gut microbiota. This is important in cholelithiasis, given that changes in the production of bile acids may affect gallbladder microbial communities. Our aim was to assess the association between regular dietary intake and gallbladder microbial composition. Fourteen adults with cholelithiasis and 14 controls, sex-age-matched and without gastrointestinal pathology, were included. Diet was assessed through a food frequency questionnaire and quantification of gallbladder microbiota sequences by Illumina 16S rRNA gene-based analysis. The cholelithiasic patients showed greater intake of potatoes and lower consumption of vegetables, non-alcoholic drinks, and sauces, which resulted in a lower intake of energy, lipids, digestible polysaccharides, folate, calcium, magnesium, vitamin C, and some phenolic compounds. Regarding the altered bile microorganisms in cholelithiasic patients, dairy product intake was negatively associated with the proportions of Bacteroidaceae and Bacteroides, and several types of fiber, phenolics, and fatty acids were linked to the abundance of Bacteroidaceae, Chitinophagaceae, Propionibacteraceae, Bacteroides, and Escherichia-Shigella. These results support a link between diet, biliary microbiota, and cholelithiasis., This research was funded by the Spanish “Plan Estatal de I+D+i” Grant number (AGL2013-44761-P) I. Gutiérrez-Díaz was supported by “Plan Regional de Investigación del Principado de Asturias” Grant number (GRUPIN14-043).

Despite the evidence regarding the influence of certain polyphenol food sources on the metabolic profile in feces, the association between the different phenolics provided by the diet and the fecal phenolic profile has not been elucidated. In this study, the composition of phenolic metabolites in fecal solutions was analyzed by UPLC-ESI-MS/MS in 74 volunteers. This fecal phenolic profile showed a high interindividual variation of the different compounds analyzed, phenylacetic and phenylpropionic acids being the major classes of phenolic metabolites excreted in feces. Subjects with higher adherence to a Mediterranean dietary pattern presented greater fecal concentrations of benzoic and 3-hydroxyphenylacetic acids, positively correlated with the intake of the principal classes and subclasses of polyphenols and fibers, and higher levels of Clostridium cluster XVIa and Faecalibacterium prausnitzii. These results provide a link among the Mediterranean dietary pattern, the bioactive compounds of the diet, and the fecal metabolic phenolic profile., This work was funded through the Grant GRUPIN14-043 “Microbiota Humana, Alimentacion y Salud from Plan Regional de Investigacion del Principado de Asturias, Spain, and by a grant from Biopolis SL. within the framework of the e-CENIT Project SENIFOOD from the Spanish Ministry of Science and Innovation, and the Project AGL2015-64522-C2-R from the Spanish MINECO. N.S. was the recipient of a postdoctoral contract supported by a Clarin regional grant (ACB 14-08) cofinanced by the Marie Curie CoFund European Program.

Obesity has been related to an increased risk of multiple diseases in which oxidative stress and inflammation play a role. Gut microbiota has emerged as a mediator in this interaction, providing new mechanistic insights at the interface between fat metabolism dysregulation and obesity development. Our aim was to analyze the interrelationship among obesity, diet, oxidative stress, inflammation and the intestinal microbiota in 68 healthy adults (29.4% normal-weight). Diet was assessed through a food frequency questionnaire and converted into nutrients and dietary compounds using food composition tables. The intestinal microbiota was assessed by quantitative PCR, fecal short chain fatty acids by gas chromatography and serum biomarkers by standard protocols. Higher levels of malondialdehyde (MDA), C reactive protein (CRP), serum leptin, glucose, fat percentage and the intestinal Lactobacillus group were found in the obese people. Cluster analysis of body mass index, fat mass, glucose, LDL/HDL ratio, leptin, MDA and CRP classified the subjects into two groups. The levels of the intestinal Bacteroides-Prevotella-Porphyromonas group were lower in the cluster and linked to a higher pro-oxidant and pro-inflammatory status, whose individuals also had lower intake of fruits, dried fruits, and fish. These results could be useful for designing strategies targeted to obesity prevention., This work was funded through the Grant GRUPIN14-043 “Microbiota Humana, Alimentación y Salud” funded by “Plan Regional de Investigación del Principado de Asturias”, Spain, by grants AGL2010-14952 from Spanish “Plan Nacional I + D + I”, by Biopolis group S.L., Valencia, within the framework of the e-CENIT Project SENIFOOD from the Spanish Ministry of Science and Innovation, and by the Alimerka Foundation. NS was the recipient of a postdoctoral contract supported by a Clarin regional grant (ACB 14-08) cofinanced by the Marie Curie CoFund European Program and IG-D benefits for a grant supported by Fundación Universia. Regional and national grants received cofounding from European Union FEDER funds. We show our greatest gratitude to all the volunteers participating in the study. We acknowledge support of the publicationfee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resourdes for Research (URICI)

[Purpose] Short-chain fatty acids (SCFAs) formation by intestinal bacteria is regulated by many different factors, among which dietary fibre is currently receiving most attention. However, since fibre-rich foods are usually good dietary sources of phenolic compounds, which are also known to affect the microbiota, authors hypothesize that the regular intake of these bioactive compounds could be associated with a modulation of faecal SCFA production by the intestinal microbiota. [Methods] In this work, food intake was recorded by means of a validated Food Frequency Questionnaire. Fibres were determined using Marlett food composition tables, and phenolic compounds were obtained from Phenol-Explorer Database. Analysis of SCFA was performed by gas chromatography–flame ionization/mass spectrometry and quantification of microbial populations in faeces by quantitative PCR. [Results] Klason lignin and its food contributors, as predictors of faecal butyrate production, were directly associated with Bacteroides and Bifidobacterium levels, as well as lignans with Bacteroides. Also, anthocyanidins, provided by strawberries, were associated with faecal propionate and inversely related to Lactobacillus group. [Conclusions] These results support the hypothesis we put forward regarding the association between some vegetable foods (strawberries, pasta, lentils, lettuce and olive oil) and faecal SCFA. More studies are needed in order to elucidate whether these associations have been mediated by the bacterial modulatory effect of the bioactive compounds, anthocyanins, lignans or Klason lignin, present in foodstuffs., This study was financed by the Spanish Plan Nacional de I+D (Grant AGL2010-14952) and by Biópolis SL. within the framework of the e-CENIT Project SENIFOOD from the Spanish Ministry of Science and Innovation. The activity of the group is being partly supported through the Grant GRUPIN14-043 from “Plan Regional de Investigación” of Principado de Asturias. Both AGL2010-14952 and GRUPIN14-043 received cofounding from European Union FEDER funds. N. Salazar benefits from a “Clarín” postdoctoral contract (Marie Curie European CoFund Program) co-funded by the “Plan Regional de Investigación” of Principado de Asturias, Spain. B. Sánchez was the recipient of a “Ramón y Cajal” postdoctoral contract from the Spanish Ministry of Economy and Competitiveness. The contract of I. Gutierrez-Diaz was supported by grant GRUPIN14-043. We acknowledge the excellent technical assistance of Lidia Alaez, whose contract was partially supported by the Project AGL2010-16525 and by “Plan Regional de Investigación” of Principado de Asturias, through the Grant COF 13-020. We show our greatest gratitude to all the volunteers participating in the study and to “Alimerka Foundation”.