Effect of overweight on gastrointestinal microbiology and immunology: correlation with blood biomarkers

Br J Nutr. 2010 Apr;103(7):1070-8. doi: 10.1017/S0007114509992807. Epub 2009 Nov 24.


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.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Bacteria* / classification
  • Bacteria* / metabolism
  • Biomarkers / blood
  • Blood Glucose*
  • C-Reactive Protein / metabolism
  • Cross-Sectional Studies
  • Fatty Acids / metabolism
  • Feces / chemistry
  • Feces / microbiology
  • Female
  • Hormones / blood*
  • Humans
  • Hydroxy Acids / metabolism
  • Inflammation Mediators / blood*
  • Insulin / blood
  • Interleukin-6 / blood
  • Intestinal Mucosa / metabolism
  • Intestines / immunology
  • Intestines / microbiology*
  • Lipids / blood*
  • Male
  • Middle Aged
  • Obesity / blood
  • Obesity / immunology*
  • Phenols / metabolism
  • Reference Values
  • Waist Circumference


  • Biomarkers
  • Blood Glucose
  • Fatty Acids
  • Hormones
  • Hydroxy Acids
  • Inflammation Mediators
  • Insulin
  • Interleukin-6
  • Lipids
  • Phenols
  • C-Reactive Protein