Methanobrevibacter smithii

- Abundance associated with higher bacterial gene richness in the gut

- Higher amounts reported in anorexia, in contrast, one study confirmed a positive association with increased BMI and body fat in methanogen-colonized populations

- Higher levels linked to IBS-C (Irritable Bowel Syndrome with Constipation)

- Methanogens found higher in people with colon cancer, colonic polyposis, ulcerative colitis and diverticular disease (sigmoidoscopy enema samples)

- Some studies have reported lower counts in IBD conversely, other have reported Increased abundance

- Lower counts of Methanobrevibacter species reported in human obesity

- Reduced levels linked with IBS-D (Irritable Bowel Syndrome with diarrhea)

- Some studies have reported lower counts in IBD (Inflammatory Bowel Disease) conversely, other have reported Increased abundance

Methanobrevibacter smithii is highly prevalent in the human gut. Lower counts have been associated with obesity while higher amounts have been associated with anorexia.