Table 6.

Human studies of the gut microbiota in obesity.

Reference	Authors	Year of Study	Subjects	Study Findings for Obese vs. Control
[108]	Da Selva	2020	21 children with obesity/overweight vs. 30 healthy (Caribbean island of Trinidad)	Reduced alpha diversity was shown compared to lean children. Firmicutes was associated with overweight/obese children. Bifidobacterium was associated with healthy weight children.
[109]	Gao et al.	2018	71 obese and 22 overweight vs. 25 healthy	Reduced gut microbial diversity and reduced beneficial bacteria, e.g., Faecalibacterium, Bifidobacterium, and Ruminococcaceae. Increased levels of Proteobacteria (Pseudomonas, Fusobacterium, Escherichia, and Shigella).
[110]	Kalliomäki et al.	2008	25 obese vs. 24 normal children (prospective follow-up study from children 3 months to 7 years)	Children who had higher levels of Bifidobacteria maintained a normal weight over time, whereas children who had greater levels of Staphylococcus aureus became overweight.
[111]	Collado et al.	2008	18 overweight pregnant women vs. 36 normal-weight pregnant women (prospective follow-up study during pregnancy)	High Bacteroidetes concentrations before pregnancy were associated with excessive weight gain during pregnancy. BMI and mother’s weight correlated with concentrations of Clostridium, Bacteroidetes, and Staphylococcus. Microbial counts were increased in the third trimester of pregnancy compared to the first trimester.