Dietary Polyphenols

Presents recent research on metabolism and the health effects of polyphenolsConsumer interest in the health benefits of many phenolic compounds found in plant foods and derivatives has grown considerably in recent years, giving rise to an increased demand for functional foods. Although preclinical and observational studies have promoted the protective properties of polyphenols for a range of chronic diseases, evidence has shown that most dietary polyphenols have little bioavailability. Once ingested, most of them are metabolized by either the intestinal enzymes or by the gut microbiota and then undergo extensive phase-II metabolism reaching significant concentrations of conjugated metabolites. They remain in the systemic circulation and target systemic tissues where trigger biological effects. The polyphenol-derived metabolites produced in humans are dependent upon the composition of the gut microbiota and the subject genetics. Thus all the metabolites do not show the same biological activity in different individuals. To fully understand the health effects of polyphenols, further clinical investigations are required.Dietary Polyphenols describes the latest findings on the polyphenol metabolism and reviews the current evidence on their health effects and that of their bioavailable metabolites. Emphasizing the importance of interindividual variability and the critical role of gut microbiota, this authoritative volume features contributions from recognized experts in the field, exploring specific families of extractable and non-extractable phenolic compounds that exhibit potential health effects. Topics include structural diversity of polyphenols and distribution in foods, bioavailability and bioaccessibility of phenolics, metabolism, and gastrointestinal absorption of various metabolites and their health effects. This comprehensive volume: Discusses the bioavailability, bioaccessibility, pharmacokinetics studies, and microbial metabolism of different groups of phenolic compoundsExamines the interaction between polyphenols and gut microbiotaDescribes analytical methods for identifying and quantifying polyphenols in foods and biological samplesReviews recent epidemiological and clinical intervention studies showing protective effects of polyphenolsDietary Polyphenols: Metabolism and Health Effects is an important resource for scientists working in the area of dietary polyphenols and health effects, microbiota, and their interaction with other nutritional compounds, and for health professionals, nutritionists, dieticians, and clinical researchers with interest in the role of polyphenols in the prevention and treatment of chronic diseases.

List of Contributors xv1 Structural Diversity of Polyphenols and Distribution in Foods 1Antonio González-Sarrías, Francisco A. Tomás-Barberán, and Rocío García-Villalba1.1 Introduction 11.2 Classification and Chemistry of Polyphenols 21.2.1 Flavonoids 21.2.2 Nonflavonoids 71.3 Dietary Intake and Food Sources of Polyphenols 101.3.1 Flavonoids 111.3.2 Nonflavonoids 141.4 Databases Used to Assess Dietary Exposure to Polyphenols 161.5 Bioavailability, Metabolism, and Bioactivity of Dietary Polyphenols 17Acknowledgments 20References 202 Nonextractable Polyphenols: A Relevant Group with Health Effects 31Yuridia Martínez-Meza, Rosalía Reynoso-Camacho, and Jara Pérez-Jiménez2.1 Introduction: The Concept of Nonextractable Polyphenols (NEPP) 312.2 Contribution of NEPP to Total Polyphenol Content and Intake 332.2.1 Strategies for the Extraction and Analysis of NEPP 342.2.2 NEPP Content in Common Foods 382.2.3 Estimation of NEPP Intake in Different Populations 402.3 Metabolic Fate of NEPP: A Key Process for Their Health Effects 422.3.1 Current Evidence of the Metabolic Transformation of NEPP 422.3.2 Specific Features of the Metabolic Fate of NEPP 462.4 How NEPP may Exhibit Health Effects 482.4.1 Antioxidant Effects 482.4.2 Microbiota Modulation 512.4.3 Biological Activities of Microbial Metabolites 532.4.4 Synergy with Dietary Fiber 582.5 Studies on the Health Effects of NEPP 602.5.1 Local vs Systemic Effects 602.5.2 Effects on Gastrointestinal Health 622.5.3 Effects on Cardiometabolic Health 642.6 Perspectives 66References 683 Analytical Strategies for Determining Polyphenols in Foods and Biological Samples 85Lucía Olmo-García, Romina P. Monasterio, Aadil Bajoub, and Alegría Carrasco-Pancorbo3.1 Introduction: Importance of the Determination of Polyphenols 853.2 Most Widely Used Extraction Systems and New Trends 893.3 Determination of the Phenolic Compounds in Foods 923.3.1 Classic Methods For Polyphenols Determination: Spectrophotometric Assays 923.3.2 Evolution of the Traditional Methods to Characterize the Polyphenolic Fraction of Foods: Chromatographic and Electrophoretic Separation and Subsequent Detection 943.3.3 Other Analytical Strategies 1063.4 Some Considerations Regarding the Determination of Polyphenols in Biological Samples 1073.5 Conclusions and Future Directions 111Acknowledgments 116References 1164 Hydroxycinnamates 129Iziar A. Ludwig, Laura Rubió, Alba Macià, and Maria P. Romero4.1 Introduction 1294.2 Metabolism of Hydroxycinnamates and Metabolic Pathways 1304.2.1 Absorption in the Upper Gastrointestinal Tract 1354.2.2 Absorption in the Lower Gastrointestinal Tract 1364.3 Bioaccessibility and Bioavailability of Hydroxycinnamates: Influence of Food Matrix, Processing, Dose, and Interindividual Differences 1384.3.1 Bioavailability of Hydroxycinnamates in Fruits, Vegetables, and Beverages 1394.3.2 Bioavailability in Cereal-Based Products 1444.4 Biological Activity of Hydroxycinnamates and Their Derivatives 148References 1535 Flavonols and Flavones 163Cláudia Nunes dos Santos, Regina Menezes, Diogo Carregosa, Katerina Valentova, Alexandre Foito, Gordon McDougall, and Derek Stewart5.1 Introduction 1635.2 Uptake and Metabolism of Flavonols and Flavones 1675.2.1 Flavonols or 3-Hydroxyflavones (Quercetin, Kaempferol, Myricetin) 1675.2.2 Flavones (Luteolin, Apigenin) 1705.3 Microbiota Formation of Low Molecular Weight Phenolic, Common Colonic Metabolites 1735.3.1 Flavonols (Quercetin, Kaempferol, Myricetin) 1735.3.2 Flavones (Luteolin, Apigenin) 1755.4 Health Effects of Flavonol and Flavone Metabolites 1775.4.1 Flavonols or 3-Hydroxyflavones 1775.4.2 Flavones (Luteolin, Apigenin) 1815.4.3 Flavonols, Flavones and Their Low Molecular Weight Colonic Metabolites in Health 1845.5 Conclusions and Future Perspectives 185Acknowledgments 186References 1866 Isoflavones 199Cara L. Frankenfeld6.1 Uptake and Metabolism of Isoflavones 1996.1.1 Gut Microbial Metabolism 1996.1.2 Pharmacokinetic Studies 2016.2 Biological Mechanisms of Isoflavones 2036.2.1 Hormonal 2036.2.2 Antioxidant 2046.2.3 Antiinflammatory 2056.3 Physiological and Health Effects of Isoflavones 2056.3.1 Bone 2066.3.2 Cancer 2086.3.3 Reproductive Hormones 2126.3.4 Cardiovascular Disease, Blood Triglycerides and Cholesterol, and Inflammatory Markers 2136.3.5 Diabetes, Insulin Resistance, and Blood Glucose and Insulin 2166.3.6 Obesity 2176.3.7 Menopausal Symptoms 2186.3.8 Neurological Outcomes 2186.4 Physiological and Health Effects of Isoflavone Metabolites and Metabotypes 2196.5 Summary of Isoflavone Intake and Health 221References 2217 Dietary Anthocyanins 245Iva Fernandes, Hélder Oliveira, Cláudia Marques, Ana Faria, Conceição Calhau, Nuno Mateus, and Victor de Freitas 7.1 Absorption and Metabolism of Anthocyanins 2457.1.1 Oral Cavity Absorption 2487.1.2 Gastric Absorption 2517.1.3 Intestinal Absorption 2547.1.4 Microbial Metabolism 2557.2 Pharmacokinetics of Anthocyanins 2587.3 Factors Affecting Anthocyanin Bioavailability 2597.4 Biological Activity of Anthocyanin Metabolites 2627.4.1 Phase II Metabolites 2657.5 Conclusion 272References 2728 Flavan-3-ols: Catechins and Proanthocyanidins 283Claudia Favari, Pedro Mena, Claudio Curti, Daniele Del Rio, and Donato Angelino8.1 Introduction: Chemistry and Main Dietary Sources 2838.2 Bioavailability of Flavan-3-ols 2888.2.1 Absorption and Metabolism: Native and Colonic Phase II Metabolites 2898.2.2 Pharmacokinetics and Urinary Excretion of Circulating Metabolites: Interindividual Differences 2938.3 Health Benefits of Flavan-3-ols and Their Derived Circulating Metabolites 2988.3.1 Cognitive 2998.3.2 Inflammation and Cardiometabolic Diseases 3028.3.3 Urinary Tract Infections 3058.4 Conclusions and Future Perspectives 307References 3089 Ellagitannins and Their Gut Microbiota-Derived Metabolites: Urolithins 319Rocío García-Villalba, Juan A. Giménez-Bastida, María A. Ávila-Gálvez, Francisco A. Tomás-Barberán, Juan C. Espín, and Antonio González-Sarrías9.1 Chemistry and Sources of Ellagitannins and Ellagic Acid 3199.2 Bioavailability of Ellagitannins and Ellagic Acid 3239.3 The Microbial Metabolism of Ellagitannins and Ellagic Acid: Urolithins 3249.3.1 Urolithin Production and Bioavailability 3249.3.2 Tissue Distribution of Urolithins after Consumption of Ellagitannins 3289.3.3 Interaction of ETs and Urolithins with the Gut Microbiota 3299.3.4 Interindividual Variability: Metabotypes 3319.3.5 Analysis of Urolithins 3329.4 Significance of Ellagitannins, Ellagic Acid, and Urolithins for Human Health 3359.4.1 Antioxidant Effects 3369.4.2 Antiinflammatory Properties 3389.4.3 Anticarcinogenic Effects 3409.4.4 Neuroprotective Effects 3439.4.5 Estrogenic Modulation 3449.4.6 Urolithins, Clinical Trials, and Interindividual Variability-Health Relationship 3459.5 Conclusion 347Acknowledgments 348References 34810 Lignans 365Knud E. Bach Knudsen, Natalja Nørskov, Anne K. Bolvig, Mette Skou Hedemann, and Helle Nygaard Lærke10.1 Introduction 36510.2 Lignans in Foods 36810.3 Metabolism of Lignans 37310.3.1 Kinetics of Absorption of Plant Lignans 37610.3.2 Conversion of Plant Lignans to Enterolignans 38210.4 Blood Levels of Lignans after Dietary Intervention 38710.5 Bioactivity of Plant Lignans and Enterolignans 39310.6 Conclusions and Future Perspectives 394Acknowledgments 395References 39511 Stilbenes: Beneficial Effects of Resveratrol Metabolites in Obesity, Dyslipidemia, Insulin Resistance, and Inflammation 407Itziar Eseberri, Iñaki Milton-Laskibar, Alfredo Fernández-Quintela, Saioa Gómez-Zorita, and María P. Portillo11.1 Introduction: Occurrence and Intake 40711.2 Absorption, Metabolism, and Excretion of Resveratrol 40811.3 Biological Effects of Resveratrol Metabolites 41211.3.1 In vitro Studies 41311.3.2 In vivo Studies 42811.4 Conclusion 429Acknowledgments 429References 43012 Flavanones 439Gema Pereira-Caro, Colin D. Kay, Michael N. Clifford, and Alan Crozier12.1 Introduction 43912.2 Flavanones and Their Occurrence 44112.3 Absorption of Flavanone Metabolites in the Proximal and Distal Gastrointestinal Tract 44312.4 Formation of 3-(3'-Hydroxy-4'-Methoxyphenyl) Hydracrylic Acid 45412.5 Factors Affecting the Bioavailability of Flavanones 45712.5.1 Impact of Physical Activity 45712.5.2 Matrix Effects 45812.5.3 Probiotics 45912.5.4 Inter- and Intraindividual Variability 46012.5.5 Other Effects 46212.6 Analysis of Flavanone Metabolites and Catabolites 46212.7 Biomarkers and Metabolomics 46512.8 Protective Effects 46712.8.1 Cardiovascular Disease 46812.8.2 Diabetic and Metabolic Syndrome 47112.8.3 Cancer 47212.8.4 Cognition and Neuroprotection 47312.8.5 Bones 47412.8.6 Liver 47412.8.7 Immunomodulation and Antiinflammatory Activity 47412.8.8 Gastric Function and the Microbiome 47512.8.9 Modulation of the Microbiota and Biological Activity of Microbial Metabolites 475References 47913 Understanding Polyphenols' Health Effects Through the Gut Microbiota 497Maria V. Selma, Francisco A. Tomás-Barberán, Maria Romo-Vaquero, Adrian Cortés-Martín, and Juan C. Espín13.1 Microbial Metabolism of Dietary Polyphenols 49713.2 Bacteria Responsible for Dietary Polyphenols Transformations and Health Implications 50713.3 Modulation of Gut Microbiota by Dietary Polyphenols 516Acknowledgments 519References 519Index 533