TABLE 1.
Association between the gut microbiota and obesity1
| Study (reference) | Description | Results |
| Le Chatelier et al. 2013 (17) | Danish obese (n = 169) and nonobese (n = 123) adults; case-control; metagenomics | 15,894 bacterial genes differed between groups. |
| Bimodal distribution of bacterial genes: 23% of individuals with low microbiome richness (<480,000 genes), 77% with high microbiome richness (>480,000 genes); 9 species and 51 intestinal metabolic pathways differed between individuals with low and high microbiome richness. | ||
| Turnbaugh et al. 2009 (13) | North American obese and normal weight monozygotic (n = 31) and dizygotic (n = 23) adult twin pairs, and their mothers (n = 46); cross-sectional design; pyrosequencing | 383 microbial genes differed between obesity and normal weight. Reduced microbial diversity in obesity. |
| Kalliomäki et al. 2008 (108) | Finnish overweight (n = 25) and normal weight (n = 24) children; longitudinal cohort study (prospective); FISH and qPCR | Bifidobacterium species increased and Staphylococcus aureus decreased in infancy in children with normal weight compared to in children who were overweight at age 7. |
| Simões et al. 2013 (109) | Finnish obese or nonobese adult monozygotic twin pairs (n = 20); cross-sectional; qPCR and DGGE | No difference in bacterial counts between normal weight, overweight, or obesity. |
| Million et al. 2012 (110) | French obese (n = 68) and normal weight (n = 47) adults; case-control; qPCR and culture | L. paracasei, L. plantarum, B. animalis, and M. smithii associated with normal weight; L. reuteri associated with obesity. |
| Štšepetova et al. 2011 (111) | Estonian obese and nonobese adults (n = 61); cross-sectional; qPCR | Lactobacillus species positively correlated with BMI. |
| L. paracasei negatively correlated with FBG. | ||
| L. fermentum marginally negatively correlated with FBG. | ||
| Schwiertz et al. 2010 (112) | German obese and nonobese adults (n = 98); cross-sectional; qPCR | Firmicutes (mainly C. leptum) reduced and Bacteriodetes (mainly Bacteroides) increased in overweight and obesity. Bifidobacterium and Methanobrevibacter negatively correlated with BMI. |
| Armougom et al. 2009 (113) | French adolescents and adults with obesity (n = 20) or anorexia nervosa (n = 9) and healthy controls (n = 20); case-control; qPCR | Bacteroidetes and Lactobacillus species increased in obesity compared to normal- and underweight. |
1
All studies are based on analyses of stool samples and are listed in order of priority according to the quality of the methods used. Description is given as population (n); design; technique. DGGE, denaturing gradient gel electrophoresis; FBG, fasting blood glucose; FISH, fluorescence in situ hybridization.