All Stories

  1. Semi-dynamic in vitro digestion of alternative proteins: structural insights and peptidomics
  2. Decision analysis for the long-term effectiveness of a community-based intervention to prevent obesity: an EUREGIO project
  3. Relating tribology to astringency perception in acidic plant protein-fortified fiber-based smoothies
  4. Fecal fermentation of human ileal fluid after mango intake impacts on colonic microbiota and microbial (poly)phenol catabolism
  5. Systematic review on community-based interventions targeting prevention of overweight and obesity in children and adolescents
  6. Circulating bile acids and HOMA-IR: cross-sectional results from the RoCAV population-based study
  7. Differential effects of plant and whey protein supplementation on the human gut microbiome using MiGut, a novel in vitro gut model
  8. Prebiotic effects of whole plant-based extracts on the human colonic microbiome using a novel in vitro model (MiGut)
  9. T Cell Dysregulation in Long-COVID: Immune Profiling and the Potential Role of Short-chain Fatty Acids in Modulating T-cell Functionality
  10. Using in vitro methods to investigate individual and combined effects of prebiotics, polyphenols, and whey protein on the human gut microbiome
  11. A review on the effects of flavan-3-ols, their metabolites, and their dietary sources on gut barrier integrity
  12. Assessing long-term health outcomes and cost effectiveness of a community-based intervention to prevent obesity in Austria – development of a decision-analytic model
  13. Prebiotics in food and dietary supplements: a roadmap to EU health claims
  14. Gut microbial metabolism of bile acids modifies the effect of Mediterranean diet interventions on cardiometabolic risk in a randomized controlled trial
  15. Microbially mediated phenolic catabolites exert differential genoprotective activities in normal and adenocarcinoma cell lines
  16. Correction to: Out with the old, and in with the new: a message from the Editor-in-Chiefs
  17. Effects of Ferulic Acid on Cognitive Function: A Systematic Review
  18. Out with the old, and in with the new: a message from the Editor-in-Chiefs
  19. In vitro faecal fermentation of Tritordeum breads and its effect on the human gut health
  20. (Poly)phenol-related gut metabotypes and human health: an update
  21. Successful weight regain attenuation by autologous fecal microbiota transplantation is associated with non-core gut microbiota changes during weight loss; randomized controlled trial
  22. Microbially-Mediated Phenolic Catabolites Exert Differential Geno-Protective Activities in Normal and Adenocarcinoma Cell Lines
  23. Soil bacterial communities under slash and burn in Mozambique as revealed by a metataxonomic approach
  24. Association between diet and circulating bile acids in an italian general population
  25. Chronic consumption of probiotics, oats, and apples has differential effects on postprandial bile acid profile and cardiometabolic disease risk markers compared with an isocaloric control (cornflakes): a randomized trial
  26. IUNS 22nd International Congress of Nutrition – Abstracts
  27. A comparative study of genoprotective activity of phenolic catabolites between normal and adenocarcinoma colonic cells in vitro
  28. Long-term supplementation with anthocyanin-rich or -poor Rubus idaeus berries does not influence microvascular architecture nor cognitive outcome in the APP/PS-1 mouse model of Alzheimer’s disease
  29. Microbial and metabolic characterization of organic artisanal sauerkraut fermentation and study of gut health-promoting properties of sauerkraut brine
  30. The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial
  31. Sourdough performances of the golden cereal Tritordeum: Dynamics of microbial ecology, biochemical and nutritional features
  32. Modulation of postprandial plasma bile acids and glycaemic control by probiotics, apples and oats – Findings from the randomised controlled cabala diet and health study
  33. Benefits of dietary fibre for children in health and disease
  34. The effects of the Green-Mediterranean diet on cardiometabolic health are linked to gut microbiome modifications: a randomized controlled trial
  35. Impact of wheat aleurone on biomarkers of cardiovascular disease, gut microbiota and metabolites in adults with high body mass index: a double-blind, placebo-controlled, randomized clinical trial
  36. Ex Vivo Fecal Fermentation of Human Ileal Fluid Collected After Wild Strawberry Consumption Modulates Human Microbiome Community Structure and Metabolic Output and Protects Against DNA Damage in Colonic Epithelial Cells
  37. The Prebiotic Effects of Oats on Blood Lipids, Gut Microbiota, and Short-Chain Fatty Acids in Mildly Hypercholesterolemic Subjects Compared With Rice: A Randomized, Controlled Trial
  38. Low-Molecular-Weight Seaweed-Derived Polysaccharides Lead to Increased Faecal Bulk but Do Not Alter Human Gut Health Markers
  39. Measuring the effect of Mankai® (Wolffia globosa) on the gut microbiota and its metabolic output using an in vitro colon model
  40. Low-Dose Lactulose as a Prebiotic for Improved Gut Health and Enhanced Mineral Absorption
  41. Massive Survey on Bacterial–Bacteriophages Biodiversity and Quality of Natural Whey Starter Cultures in Trentingrana Cheese Production
  42. The Metabolomic-Gut-Clinical Axis of Mankai Plant-Derived Dietary Polyphenols
  43. Processed Animal Proteins from Insect and Poultry By-Products in a Fish Meal-Free Diet for Rainbow Trout: Impact on Intestinal Microbiota and Inflammatory Markers
  44. Ex vivo fecal fermentation of human ileal fluid collected after raspberry consumption modifies (poly)phenolics and modulates genoprotective effects in colonic epithelial cells
  45. Effect of green-Mediterranean diet on intrahepatic fat: the DIRECT PLUS randomised controlled trial
  46. Microbial community dynamics in phyto-thermotherapy baths viewed through next generation sequencing and metabolomics approach
  47. Large scale genome reconstructions illuminate Wolbachia evolution
  48. Shift in the cow milk microbiota during alpine pasture as analyzed by culture dependent and high-throughput sequencing techniques
  49. Gut microbiota associations with diet in irritable bowel syndrome and the effect of low FODMAP diet and probiotics
  50. Healthy dietary patterns to reduce obesity-related metabolic disease
  51. Nutrition and the ageing brain: Moving towards clinical applications
  52. Baricitinib counteracts metaflammation, thus protecting against diet-induced metabolic abnormalities in mice
  53. 56th EASD Annual Meeting of the European Association for the Study of Diabetes
  54. Effects of Exogenous Dietary Advanced Glycation End Products on the Cross-Talk Mechanisms Linking Microbiota to Metabolic Inflammation
  55. Manipulation of dietary amino acids and energy homeostasis
  56. Effects of Diet-Modulated Autologous Fecal Microbiota Transplantation on Weight Regain
  57. Biennial European Meeting of the Society for Medical Decision Making Berlin, Germany, June 14-16, 2020, postponed to 2022
  58. Effects of Lactobacillus spp. on the phytochemical composition of juices from two varieties of Citrus sinensis L. Osbeck: ‘Tarocco’ and ‘Washington navel’
  59. Considerations for the design and conduct of human gut microbiota intervention studies relating to foods
  60. Intestinal Organoids: A Tool for Modelling Diet–Microbiome–Host Interactions
  61. Poster Presentations
  62. Two apples a day modulate human:microbiome co-metabolic processing of polyphenols, tyrosine and tryptophan
  63. PROBIOTICS, PREBIOTICS & NEW FOODS, NUTRACEUTICALS AND BOTANICALS for NUTRITION & HUMAN and MICROBIOTA HEALTH
  64. Advanced glycation end products (AGEs) in metabolic disease: linking diet, inflammation and microbiota
  65. Food & Nutrition: The driving factors of our gut microbes
  66. Impact of proanthocyanidin-rich apple intake on gut microbiota composition and polyphenol metabolomic activity in healthy mildly hypercholesterolemic subjects
  67. Measuring phenolic compounds in Mankai: a novel polyphenol and amino rich plant protein source
  68. Production of conjugated linoleic acid (CLA): effect of inulin on microbial composition and CLA concentration in a human intestinal model
  69. Wild strawberry polyphenols exhibit gut-protective bioactivity following in vivo digestion
  70. Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, crossover trial
  71. Hermetia illucens in diets for zebrafish (Danio rerio): A study of bacterial diversity by using PCR-DGGE and metagenomic sequencing
  72. In vitro probiotic characterization of high GABA producing strain Lactobacilluas brevis DSM 32386 isolated from traditional “wild” Alpine cheese
  73. Gamma-aminobutyric acid-producing lactobacilli positively affect metabolism and depressive-like behaviour in a mouse model of metabolic syndrome
  74. Biomarkers of cereal food intake
  75. Isotopic dilution method for bile acid profiling reveals new sulfate glycine-conjugated dihydroxy bile acids and glucuronide bile acids in serum
  76. Metformin and Dipeptidase Peptidyl-4 Inhibitor Differentially Modulate the Intestinal Microbiota and Plasma Metabolome of Metabolically Dysfunctional Mice
  77. Digestion and Colonic Fermentation of Raw and Cooked Opuntia ficus-indica Cladodes Impacts Bioaccessibility and Bioactivity
  78. Production of Naturally γ-Aminobutyric Acid-Enriched Cheese Using the Dairy Strains Streptococcus thermophilus 84C and Lactobacillus brevis DSM 32386
  79. Evaluation of autochthonous lactic acid bacteria as starter and non-starter cultures for the production of Traditional Mountain cheese
  80. Gut microbiota and health: connecting actors across the metabolic system
  81. Host: Microbiome co -metabolic processing of dietary polyphenols – An acute, single blinded, cross-over study with different doses of apple polyphenols in healthy subjects
  82. Applying novel approaches for GC × GC-TOF-MS data cleaning and trends clustering in VOCs time-series analysis
  83. Breakthroughs in the Health Effects of Plant Food Bioactives: A Perspective on Microbiomics, Nutri(epi)genomics, and Metabolomics
  84. Microbial dynamics of model Fabriano-like fermented sausages as affected by starter cultures, nitrates and nitrites
  85. Connecting the immune system, systemic chronic inflammation and the gut microbiome: The role of sex
  86. The bacterial biota of laboratory-reared edible mealworms ( Tenebrio molitor L.): From feed to frass
  87. Current evidence linking diet to gut microbiota and brain development and function
  88. Impact of ageing and a synbiotic on the immune response to seasonal influenza vaccination; a randomised controlled trial
  89. Age-Related Changes in the Natural Killer Cell Response to Seasonal Influenza Vaccination Are Not Influenced by a Synbiotic: a Randomised Controlled Trial
  90. Prebiotic Wheat Bran Fractions Induce Specific Microbiota Changes
  91. Gut : liver : brain axis: the microbial challenge in the hepatic encephalopathy
  92. Measuring the impact of olive pomace enriched biscuits on the gut microbiota and its metabolic activity in mildly hypercholesterolaemic subjects
  93. A Diet Low in FODMAPs Reduces Symptoms in Patients With Irritable Bowel Syndrome and A Probiotic Restores Bifidobacterium Species: A Randomized Controlled Trial
  94. How do probiotics and prebiotics function at distant sites?
  95. Impact of thistle rennet from Carlina acanthifolia All. subsp. acanthifolia on bacterial diversity and dynamics of a specialty Italian raw ewes' milk cheese
  96. Development of a fast and cost-effective gas chromatography–mass spectrometry method for the quantification of short-chain and medium-chain fatty acids in human biofluids
  97. Gut microbiota: Inulin regulates endothelial function: a prebiotic smoking gun?
  98. Effects of Commercial Apple Varieties on Human Gut Microbiota Composition and Metabolic Output Using an In Vitro Colonic Model
  99. Gut microbiota functions: metabolism of nutrients and other food components
  100. Exploring the microbiota of the red-brown defect in smear-ripened cheese by 454-pyrosequencing and its prevention using different cleaning systems
  101. Monitoring of wheat lactic acid bacteria from the field until the first step of dough fermentation
  102. Erratum to: Evolution of gut microbiota composition from birth to 24 weeks in the INFANTMET Cohort
  103. Evolution of gut microbiota composition from birth to 24 weeks in the INFANTMET Cohort
  104. In vitro evaluation of prebiotic properties derived from rice bran obtained by debranning technology
  105. Hypocholesterolemic and Prebiotic Effects of a Whole-Grain Oat-Based Granola Breakfast Cereal in a Cardio-Metabolic “At Risk” Population
  106. Insulin Resistance, Microbiota, and Fat Distribution Changes by a New Model of Vertical Sleeve Gastrectomy in Obese Rats
  107. Nutrition challenges ahead
  108. Effect of a synbiotic on the response to seasonal influenza vaccination is strongly influenced by degree of immunosenescence
  109. Microbial evolution of traditional mountain cheese and characterization of early fermentation cocci for selection of autochtonous dairy starter strains
  110. Urinary metabolomic profiling to identify biomarkers of a flavonoid-rich and flavonoid-poor fruits and vegetables diet in adults: the FLAVURS trial
  111. Antimicrobial activity of selected synbiotics targeted for the elderly against pathogenic Escherichia coli strains
  112. Impact of increasing fruit and vegetables and flavonoid intake on the human gut microbiota
  113. Can 2 apples a day improve cardiovascular and gut health?
  114. Habitat fragmentation is associated to gut microbiota diversity of an endangered primate: implications for conservation
  115. The gut microbiota and host health: a new clinical frontier
  116. Low-grade inflammation, diet composition and health: current research evidence and its translation
  117. Identification and characterization of wild lactobacilli and pediococci from spontaneously fermented Mountain Cheese
  118. Towards microbial fermentation metabolites as markers for health benefits of prebiotics
  119. Apples and Cardiovascular Health—Is the Gut Microbiota a Core Consideration?
  120. The Microbiota of the Human Gastrointestinal Tract
  121. A Nutritional Anthropology of the Human Gut Microbiota
  122. Population Level Divergence from the Mediterranean Diet and the Risk of Cancer and Metabolic Disease
  123. Diet and the Gut Microbiota – How the Gut
  124. Shaping the Human Microbiome with Prebiotic Foods – Current Perspectives for Continued Development**This is an update of: “Shaping the human microbiome with prebiotic foods – current perspectives for continued development.” Food Science and Technology ...
  125. List of Contributors
  126. Biodiversity andγ-Aminobutyric Acid Production by Lactic Acid Bacteria Isolated from Traditional Alpine Raw Cow’s Milk Cheeses
  127. OC38: Introduction of plasma vitamin C and Ferric Reducing Antioxidant Power into a combined biomarker with plasma carotenoids increases the association with fruit and vegetable intake
  128. Diet-Microbe Interactions in the Gut
  129. A Novel Combined Biomarker including Plasma Carotenoids, Vitamin C, and Ferric Reducing Antioxidant Power Is More Strongly Associated with Fruit and Vegetable Intake than the Individual Components
  130. Erratum
  131. An in vitro study of the effect of probiotics, prebiotics and synbiotics on the elderly faecal microbiota
  132. Xylo-oligosaccharides alone or in synbiotic combination with Bifidobacterium animalis subsp. lactis induce bifidogenesis and modulate markers of immune functi...
  133. ‘The way to a man's heart is through his gut microbiota’ – dietary pro- and prebiotics for the management of cardiovascular risk
  134. Flavonoid-rich fruit and vegetables improve microvascular reactivity and inflammatory status in men at risk of cardiovascular disease--FLAVURS: a randomized controlled trial
  135. Effects of a novel probiotic, Bifidobacterium longum bv. infantis CCUG 52486 with prebiotic on the B-cell response to influenza vaccination
  136. Apples increased the bifidobacteria population in human in vitro colonic gut model – preliminary results
  137. In vitro batch cultures of gut microbiota from healthy and ulcerative colitis (UC) subjects suggest that sulphate-reducing bacteria levels are raised in UC and by a protein-rich diet
  138. Development of antimicrobial synbiotics using potentially-probiotic faecal isolates of Lactobacillus fermentum and Bifidobacterium longum
  139. Bifidobacterium longum bv. infantis CCUG 52486 combined with gluco-oligosaccharide significantly reduces the duration of self-reported cold and flu-like symptoms among healthy older adults after seasonal influenza vaccination
  140. Effects of Bifidobacteriumlongumbv.infantisCCUG 52486 combined with glucooligosaccharideon immune cell populations in healthy young and older subjects receiving an influenza vaccination
  141. Effects of Bifidobacteriumlongum bv. Infantis CCUG 52486 combined with glucooligosaccharide on immune cell populations in healthy young and older subjects receiving an influenza vaccination
  142. β2–1 fructans have a bifidogenic effect in healthy middle-aged humans and enhance the antibody response to seasonal influenza vaccination, but do not alter immune responses examined in the absence of vaccination: results from a randomised controlled trial
  143. Differential Effects of Two Fermentable Carbohydrates on Central Appetite Regulation and Body Composition
  144. Molecular Microbial Ecology of the Human Gut
  145. Up-regulating the Human Intestinal Microbiome Using Whole Plant Foods, Polyphenols, and/or Fiber
  146. Fermentable Carbohydrate Alters Hypothalamic Neuronal Activity and Protects Against the Obesogenic Environment
  147. The type and quantity of dietary fat and carbohydrate alter faecal microbiome and short-chain fatty acid excretion in a metabolic syndrome ‘at-risk’ population
  148. Moving with the times
  149. Wholegrain oat-based cereals have prebiotic potential and low glycaemic index
  150. In vitro fermentation and prebiotic potential of novel low molecular weight polysaccharides derived from agar and alginate seaweeds
  151. Effect ofLactobacillus acidophilusNCDC 13 supplementation on the progression of obesity in diet-induced obese mice
  152. β2-1 Fructans have a bifidogenic effect in healthy middle-aged human subjects but do not alter immune responses examined in the absence of an in vivo immune challenge: results from a randomised controlled trial
  153. In Vitro Fermentation Characteristics of Whole Grain Wheat Flakes and the Effect of Toasting on Prebiotic Potential
  154. High-level dietary fibre up-regulates colonic fermentation and relative abundance of saccharolytic bacteria within the human faecal microbiota in vitro
  155. Culture‐Independent Analysis of the Human Gut Microbiota and their Activities
  156. A randomised crossover study investigating the effects of galacto-oligosaccharides on the faecal microbiota in men and women over 50 years of age
  157. Production of angiotensin-I-converting enzyme (ACE) inhibitory activity in milk fermented with probiotic strains: Effects of calcium, pH and peptides on the ACE-inhibitory activity
  158. Variation in Antibiotic-Induced Microbial Recolonization Impacts on the Host Metabolic Phenotypes of Rats
  159. Obesity and the gut microbiota: does up-regulating colonic fermentation protect against obesity and metabolic disease?
  160. In vitro measurement of the impact of human milk oligosaccharides on the faecal microbiota of weaned formula-fed infants compared to a mixture of prebiotic fructooligosaccharides and galactooligosaccharides
  161. Low glycaemic index wholegrain oat cereal consumption resulted in prebiotic and hypo-cholesterolaemic effects in those ‘at risk’ of metabolic disease
  162. A comparative in vitro investigation into the effects of cooked meats on the human faecal microbiota
  163. In vitro evaluation of the microbiota modulation abilities of different sized whole oat grain flakes
  164. Shaping the human microbiome with prebiotic foods – current perspectives for continued development
  165. Profiling of Phenols in Human Fecal Water after Raspberry Supplementation
  166. Bacterial, SCFA and gas profiles of a range of food ingredients following in vitro fermentation by human colonic microbiota
  167. Konjac glucomannan hydrolysate beneficially modulates bacterial composition and activity within the faecal microbiota
  168. Determination of thein vivoprebiotic potential of a maize-based whole grain breakfast cereal: a human feeding study
  169. Selective effects of Lactobacillus casei Shirota on T cell activation, natural killer cell activity and cytokine production
  170. Dietary prebiotics: current status and new definition
  171. A human volunteer study to assess the impact of confectionery sweeteners on the gut microbiota composition
  172. Prebiotic effect of fruit and vegetable shots containing Jerusalem artichoke inulin: a human intervention study
  173. Differential induction of apoptosis in human colonic carcinoma cells (Caco-2) by Atopobium, and commensal, probiotic and enteropathogenic bacteria: Mediation by the mitochondrial pathway
  174. The effect of different probiotic strains on immune function in vitro
  175. The in vitro prebiotic potential and glycaemic index (GI) of wholegrain-oat-based cereals
  176. Effects of Lactobacillus casei Shirota on immune function
  177. Effects of Lactobacillus casei Shirota on immune function
  178. In vitroevaluation of the fermentation properties and potential prebiotic activity of Agave fructans
  179. Editorial [Hot Topic: The Human Microbiome - A Therapeutic Target for Prevention and Treatment of Chronic Disease (Executive Editor: Kieran Tuohy)]
  180. Studying the Human Gut Microbiota in the Trans-Omics Era - Focus on Metagenomics and Metabonomics
  181. Top-Down Systems Biology Modeling of Host Metabotype−Microbiome Associations in Obese Rodents
  182. The potential role of the intestinal gut microbiota in obesity and the metabolic syndrome
  183. Post-Genomics Approaches towards Monitoring Changes within the Microbial Ecology of the Gut
  184. Gut microbiome modulates the toxicity of hydrazine: a metabonomic study
  185. Fecal microbiota in patients receiving enteral feeding are highly variable and may be altered in those who develop diarrhea
  186. Commentary on ‘Prebiotics, immune function, infection and inflammation: a review of the evidence’
  187. FAO Technical Meeting on Prebiotics
  188. Dietary glycated protein modulates the colonic microbiota towards a more detrimental composition in ulcerative colitis patients and non-ulcerative colitis subjects
  189. Effects of Resistant Starch Type III Polymorphs on Human Colon Microbiota and Short Chain Fatty Acids in Human Gut Models
  190. Inulin-Type Fructans in Healthy Aging
  191. Dietary-based gut flora modulation against Clostridium difficile onset
  192. In vitro study on gas generation and prebiotic effects of some carbohydrates and their mixtures
  193. Selective increases of bifidobacteria in gut microflora improve high-fat-diet-induced diabetes in mice through a mechanism associated with endotoxaemia
  194. Whole-grain wheat breakfast cereal has a prebiotic effect on the human gut microbiota: a double-blind, placebo-controlled, crossover study
  195. Effect of polydextrose on intestinal microbes and immune functions in pigs
  196. Metabolic Endotoxemia Initiates Obesity and Insulin Resistance
  197. In vitro evaluation of the prebiotic activity of a pectic oligosaccharide-rich extract enzymatically derived from bergamot peel
  198. Inulin: a prebiotic functional food ingredient
  199. Effects of Bovine α‐Lactalbumin and Casein Glycomacropeptide–enriched Infant Formulae on Faecal Microbiota in Healthy Term Infants
  200. Functions of the Human Intestinal Flora: The Use of Probiotics and Prebiotics
  201. The Gut Microbiota and Lipid Metabolism: Implications for Human Health and Coronary Heart Disease
  202. Survivability of a probiotic Lactobacillus casei in the gastrointestinal tract of healthy human volunteers and its impact on the faecal microflora
  203. Metabolism of Maillard reaction products by the human gut microbiota – implications for health
  204. Profiling of composition and metabolic activities of the colonic microflora of growing pigs fed diets supplemented with prebiotic oligosaccharides
  205. In Vitro Determination of Prebiotic Properties of Oligosaccharides Derived from an Orange Juice Manufacturing By-Product Stream
  206. Modulation of the Human Gut Microflora Towards Improved Health Using Prebiotics - Assessment of Efficacy
  207. Improving gut health in the elderly
  208. Molecular Identification and Anti-pathogenic Activities of Putative Probiotic Bacteria Isolated from Faeces of Healthy Elderly Individuals
  209. Molecular identification and anti-pathogenic activities of putative probiotic bacteria isolated from faeces of healthy elderly individuals
  210. Improving gut health in the elderly
  211. Using probiotics and prebiotics to improve gut health
  212. Prebiotic applications in human volunteer trials
  213. Monitoring transfer of recombinant and nonrecombinant plasmids between Lactococcus lactis strains and members of the human gastrointestinal microbiota in vivo- impact of donor cell number and diet
  214. Biosafety of marker genes
  215. A Human Volunteer Study to Determine the Prebiotic Effects of Lactulose Powder on Human Colonic Microbiota
  216. Prebiotic effects of inulin and oligofructose
  217. Prebiotic effects of inulin and oligofructose
  218. A Human Volunteer Study to Determine the Prebiotic Effects of Lactulose Powder on Human Colonic Microbiota
  219. The prebiotic effects of biscuits containing partially hydrolysed guar gum and fructo-oligosaccharides – a human volunteer study
  220. A Human Volunteer Study on the Prebiotic Effects of HP-Inulin—Faecal Bacteria Enumerated Using Fluorescent In Situ Hybridisation (FISH)
  221. Perspectives on the role of the human gut microbiota and its modulation by pro- and prebiotics
  222. The human gut flora in nutrition and approaches for its dietary modulation