Lien entre flore intestinale et obésité

[Gilles]

Deux études, publiées dans la prestigieuse revue Nature, apportent un éclairage nouveau sur l'obésité. L'obésité et ses complications seraient directement liées à la composition de la flore intestinale.

FRANCE INFO le Lundi 2 Septembre 2013 : La flore intestinale impliquée dans les complications de l'obésité

Chez 49 adultes français obèses ou en surpoids, les chercheurs ont analysé les effets d'un régime riche en protéines et en fibres, pauvre en calories. Après six semaines, ce régime a comme prévu amélioré les paramètres métaboliques et entraîné une perte de poids. Il a aussi augmenté la richesse des espèces bactériennes des sujets initialement déficitaires. Cependant, "les sujets dotés d'une flore initialement pauvre ont plus de mal à améliorer leurs paramètres inflammatoires et lipidiques", relève Karine Clément.

LE MONDE SCIENCE ET TECHNO le 02.09.2013 : Ces microbes qui nous gouvernent

[Gilles]

Première étude :
Richness of human gut microbiome correlates with metabolic markers
Emmanuelle Le Chatelier et al.
Nature 500, 541–546 (29 August 2013)

Abstract

We are facing a global metabolic health crisis provoked by an obesity epidemic. Here we report the human gut microbial composition in a population sample of 123 non-obese and 169 obese Danish individuals. We find two groups of individuals that differ by the number of gut microbial genes and thus gut bacterial richness. They contain known and previously unknown bacterial species at different proportions; individuals with a low bacterial richness (23% of the population) are characterized by more marked overall adiposity, insulin resistance and dyslipidaemia and a more pronounced inflammatory phenotype when compared with high bacterial richness individuals. The obese individuals among the lower bacterial richness group also gain more weight over time. Only a few bacterial species are sufficient to distinguish between individuals with high and low bacterial richness, and even between lean and obese participants. Our classifications based on variation in the gut microbiome identify subsets of individuals in the general white adult population who may be at increased risk of progressing to adiposity-associated co-morbidities.

http://www.nature.com/nature/journal/v5 ... 12506.html

[Gilles]

Seconde étude :
Dietary intervention impact on gut microbial gene richness
Aurélie Cotillard et al.
Nature 500, 585–588 (29 August 2013)

Abstract

Complex gene–environment interactions are considered important in the development of obesity1. The composition of the gut microbiota can determine the efficacy of energy harvest from food2, 3, 4 and changes in dietary composition have been associated with changes in the composition of gut microbial populations5, 6. The capacity to explore microbiota composition was markedly improved by the development of metagenomic approaches7, 8, which have already allowed production of the first human gut microbial gene catalogue9 and stratifying individuals by their gut genomic profile into different enterotypes10, but the analyses were carried out mainly in non-intervention settings. To investigate the temporal relationships between food intake, gut microbiota and metabolic and inflammatory phenotypes, we conducted diet-induced weight-loss and weight-stabilization interventions in a study sample of 38 obese and 11 overweight individuals. Here we report that individuals with reduced microbial gene richness (40%) present more pronounced dys-metabolism and low-grade inflammation, as observed concomitantly in the accompanying paper11. Dietary intervention improves low gene richness and clinical phenotypes, but seems to be less efficient for inflammation variables in individuals with lower gene richness. Low gene richness may therefore have predictive potential for the efficacy of intervention.

http://www.nature.com/nature/journal/v5 ... 12480.html

[Gilles]

Une émission sur le même sujet :
FRANCE-INTER le mercredi 11 septembre : La flore intestinale et les pathologies liées.

A noter vers 0h27 l'intervention de Gilles Mithieux, biologiste et directeur de l’Unité Inserm 855 : « Nutrition et Cerveau » à propos des mécanismes biologiques responsables de l’effet « coupe-faim » des protéines alimentaires.