title: Impact of increasing fruit and vegetables and flavonoid intake on the human gut microbiota.
abstract: Epidemiological studies have shown protective effects of fruits and vegetables (F&V) in lowering the risk of developing cardiovascular diseases (CVD) and cancers. Plant-derived dietary fibre (non-digestible polysaccharides) and/or flavonoids may mediate the observed protective effects particularly through their interaction with the gut microbiota. The aim of this study was to assess the impact of fruit and vegetable (F&V) intake on gut microbiota, with an emphasis on the role of flavonoids, and further to explore relationships between microbiota and factors associated with CVD risk. In the study, a parallel design with 3 study groups, participants in the two intervention groups representing high-flavonoid (HF) and low flavonoid (LF) intakes were asked to increase their daily F&V intake by 2, 4 and 6 portions for a duration of 6 weeks each, while a third (control) group continued with their habitual diet. Faecal samples were collected at baseline and after each dose from 122 subjects. Faecal bacteria enumeration was performed by fluorescence in situ hybridisation (FISH). Correlations of dietary components, flavonoid intake and markers of CVD with bacterial numbers were also performed. A significant dose X treatment interaction was only found for Clostidium leptum-Ruminococcus bromii/flavefaciens with a significant increase after intake of 6 additional portions in the LF group. Correlation analysis of the data from all 122 subjects independent from dietary intervention indicated an inhibitory role of F&V intake, flavonoid content and sugars against the growth of potentially pathogenic clostridia. Additionally, we observed associations between certain bacterial populations and CVD risk factors including plasma TNF-α, plasma lipids and BMI/waist circumference.
authors.affiliation: Department of Food and Nutritional Sciences, University of Reading, Reading, Berkshire, UK. annett.klinder@med.uni-rostock.de and Clinic of Orthopaedics, University Medicine Rostock, Rostock, Germany.
authors.forename: Annett
authors.initials: A
authors.lastname: Klinder
authors.affiliation: Department of Food and Nutritional Sciences, University of Reading, Reading, Berkshire, UK. annett.klinder@med.uni-rostock.de.
authors.forename: Qing
authors.initials: Q
authors.lastname: Shen
authors.affiliation: Department of Food and Nutritional Sciences, University of Reading, Reading, Berkshire, UK. annett.klinder@med.uni-rostock.de.
authors.forename: Susanne
authors.initials: S
authors.lastname: Heppel
authors.affiliation: Department of Food and Nutritional Sciences, University of Reading, Reading, Berkshire, UK. annett.klinder@med.uni-rostock.de.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Lovegrove
authors.affiliation: Department of Food and Nutritional Sciences, University of Reading, Reading, Berkshire, UK. annett.klinder@med.uni-rostock.de.
authors.forename: Ian
authors.initials: I
authors.lastname: Rowland
authors.affiliation: Department of Food and Nutritional Sciences, University of Reading, Reading, Berkshire, UK. annett.klinder@med.uni-rostock.de and Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Trento, Italy.
authors.forename: Kieran M
authors.initials: KM
authors.lastname: Tuohy
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control; D004032:Diet; D004435:Eating; D005243:Feces / Q000382:microbiology; D005260:Female; D005419:Flavonoids / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism*; D000069196:Gastrointestinal Microbiome; D006801:Humans; D008297:Male; D008875:Middle Aged; D014675:Vegetables / Q000378:metabolism*
chemical_list: D005419:Flavonoids