The Connection Between Leaky Gut and Arthritis

Importance of the gut

Awareness of the importance of the gut to overall health has skyrocketed in the past decade. One recent example of the surge in knowledge about the connection between gut health and systemic health is rheumatoid arthritis (RA).

Inflammatory biomarkers are known to emerge years before a definitive diagnosis of rheumatoid arthritis is possible.¹ One theory dating back to the beginning of the 20th century suggested that RA emerges from mucosal tissues and dysbiosis, and only later do problems occur in the synovial fluid and joints.^2-4 More recent research supports this chain of events.

For example, research suggests that IgA antibodies, which are closely associated with mucosa, are elevated in preclinical and recently diagnosed RA patients.⁵ People with RA have different gut microbial populations than people with other inflammatory diagnoses²—in particular, individuals newly diagnosed with RA have higher populations of Prevotella copri.⁶

A small 2019 study found significant differences in the microbial distribution of various taxa from phylum to genus levels between 25 healthy subjects and 29 early RA patients.⁷ Phylum Bacteroidetes was enriched in early RA patients, while Actinobacteria, including the genus Collinsella, was enriched in healthy subjects. Functional analysis based on clusters of orthologous groups revealed that the genes related to the biosynthesis of menaquinone, known to be derived from gram-positive bacteria, were enriched in healthy subjects, while iron transport–related genes were enriched in early RA patients. Genes related to the biosynthesis of lipopolysaccharide, the gram-negative bacterial endotoxin, were enriched in clinically apparent RA patients. Together, this research highlights the potential involvement of the gut microbiome even in the early stages of RA.⁷

Higher levels of gingival disease and unhealthy oral microbiota are also associated with the early stage of RA.8 Gut bacteria have also been found in the synovial fluid of RA mouse models, suggesting treatment of mucosal surfaces and the microbiome may curtail or affect the development and course of RA.⁹ This suggests that RA might be avoidable if the signs are recognized early enough and gut health can be restored.¹⁰