title: Effect of overweight on gastrointestinal microbiology and immunology: correlation with blood biomarkers.
abstract: A cross-sectional study was carried out in order to compare intestinal microbiological and immunological biomarkers with blood glucose and lipids, satiety-related hormones and inflammatory biomarkers characterising differences between obese and normal weight subjects. Faecal and blood samples were obtained from twenty obese subjects with an average BMI of 32.9 kg/m2 and twenty normal weight subjects with an average BMI of 23.3 kg/m2. Blood insulin, TAG and leptin were significantly elevated, whereas concentrations of HDL and ghrelin were significantly decreased in the obese subjects. Inflammatory status in the obese subjects was characterised by a trend for elevated blood C-reactive protein (CRP; P = 0.06) and IL-6 (P = 0.02). The faecal microbial composition differed between the groups; less sulphate-reducing bacteria (P = 0.05) and a trend for less Bacteroides (P = 0.07) were measured for overweight subjects. Furthermore, an inverse correlation was demonstrated between faecal Bacteroides levels and waist circumference (P = 0.05). The faecal microbial metabolites differed between the groups; increased concentrations of branched-chain fatty acids, phenolics, valeric acid, di- and hydroxy acids were described in the obese subjects. No differences between the measured intestinal inflammatory biomarkers were detected. However, systemic inflammation (CRP and IL-6) was correlated with the faecal concentrations of phenolics and lactic acid (P < 0.05 and 0.05, and P < 0.01 and 0.05, respectively). In summary, weight-related differences were observed both in the intestinal microbial composition and its activity. The role of intestinal signals, such as phenolics and lactic acid in the development of weight-related problems, needs to be studied further.
authors.affiliation: Danisco Finland Oy, Health and Nutrition, Sokeritehtaantie 20, FIN-02460 Kantvik, Finland. kirsti.tiihonen@danisco.com
authors.forename: Kirsti
authors.initials: K
authors.lastname: Tiihonen
authors.forename: Arthur C
authors.initials: AC
authors.lastname: Ouwehand
authors.forename: Nina
authors.initials: N
authors.lastname: Rautonen
mesh_terms: D000328:Adult; D001419:Bacteria / Q000145:classification / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose; D002097:C-Reactive Protein / Q000378:metabolism; D003430:Cross-Sectional Studies; D005227:Fatty Acids / Q000378:metabolism; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005260:Female; D006728:Hormones / Q000097:blood*; D006801:Humans; D006880:Hydroxy Acids / Q000378:metabolism; D018836:Inflammation Mediators / Q000097:blood*; D007328:Insulin / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000276:immunology / Q000382:microbiology*; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000276:immunology*; D010636:Phenols / Q000378:metabolism; D012016:Reference Values; D055105:Waist Circumference
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D005227:Fatty Acids; D006728:Hormones; D006880:Hydroxy Acids; D018836:Inflammation Mediators; D007328:Insulin; D015850:Interleukin-6; D008055:Lipids; D010636:Phenols; D002097:C-Reactive Protein