Overview
Roseburia intestinalis is a Gram-positive, obligate anaerobic member of the Lachnospiraceae family (Firmicutes). It is one of the most important butyrate producers in the human colon, converting dietary fiber into butyrate — the primary energy source for colonocytes and a key regulator of intestinal immune homeostasis.
Metal Dependencies
R. intestinalis requires iron for its electron transport chain and butyrate biosynthesis enzymes, yet it lacks the aggressive iron acquisition systems (siderophores) of Proteobacteria. This asymmetry means that when luminal iron rises during inflammation, iron-scavenging pathogens outcompete R. intestinalis, reducing butyrate output precisely when the gut needs it most.
Ecological Role
In a healthy, fiber-rich colon, R. intestinalis is a dominant fermenter. Its butyrate output maintains epithelial oxygen consumption, preserving the anaerobic environment that favors beneficial obligate anaerobes over facultative pathogens. Its flagellin interacts with TLR5 to promote anti-inflammatory IL-10 production. Loss of R. intestinalis initiates a vicious cycle: less butyrate, more oxygen, more Proteobacteria, more inflammation.
Conditions Associated
Depletion of R. intestinalis is a consistent signature across inflammatory bowel disease, type 2 diabetes, and colorectal cancer. Its abundance responds positively to dietary fiber interventions and negatively to high-fat, low-fiber diets and oral iron supplementation.
Cross-References
- butyrate — primary metabolic output
- iron — growth requirement, competitive vulnerability
- lachnospiraceae — taxonomic family
- dysbiosis — depleted in inflammatory states