Diet and gut dysbiosis linked to rheumatoid arthritis

Recent research explores how gut microbiome imbalances contribute to rheumatoid arthritis, and how dietary interventions could be key to reducing inflammation and improving patient outcomes.

Study: Gut Dysbiosis and Dietary Interventions in Rheumatoid Arthritis—A Narrative Review. Image Credit: VPLAB / Shutterstock.com

In a recent review published in the journal Nutrients, researchers discuss the roles of diet and gut microbiome dysbiosis in the pathogenesis of rheumatoid arthritis.

What causes rheumatoid arthritis?

Rheumatoid arthritis, which affects approximately 0.5% of the global population, is an autoimmune disease that causes inflammation in the joints of the body, especially in the hands and feet. As a result, rheumatoid arthritis can severely impact mobility, cause disability, and reduce the overall quality of life. This disease can also manifest in symptoms other than joint pain and swelling, causing nodules in the skin and lung disease.

Recent studies have suggested that the gut microbiome may be involved in the pathogenesis of rheumatoid arthritis. Considering that the gut microbiome is closely associated with immune responses and the central role of diet in modulating the gut microbiota, diet and dysbiosis may also be involved in the manifestations of this disease.

The role of the gut microbiome

The gut microbiome regulates the immune system; therefore, changes in its composition might be implicated in the pathogenesis of rheumatoid arthritis. Gut dysbiosis, defined as an imbalance in microorganisms within the gastrointestinal tract, contributes to chronic inflammation, which is one of the hallmarks of rheumatoid arthritis.

Previous studies have reported that the diversity of the gut microbiome is reduced in patients with rheumatoid arthritis. Increased abundance of Prevotella copri, for example, has been associated with new-onset rheumatoid arthritis cases. Similarities between P. copri and the molecules in the joint tissues also cause molecular mimicry, which can cause the immune system to attack cells in the joint tissues.

Increased abundance of Collinsella has also been observed in the gut microbiome of rheumatoid arthritis patients, which may lead to increased gut permeability in these patients. Thus, due to increased permeability, systemic inflammation could arise due to harmful substances passing across the intestinal barrier. Collinsella species may also stimulate the production of immune molecules like interleukin-17 (IL-17) and trigger pro-inflammatory pathways.

Conversely, a reduced abundance of beneficial bacteria like Faecalibacterium prausnitzii, Parabacteroides distasonis, Roseburia inulinivorans, and Bacteroides species that produce short-chain fatty acids (SCFAs) and reduced inflammation has been observed in the gut microbiome of rheumatoid arthritis patients. Experimental models that have supplemented the gut microbiome of rheumatoid arthritis patients with these bacteria have been shown to reduce symptoms.

The association between rheumatoid arthritis and the gut microbiome is further supported by the finding that immune cells such as T helper type 17 (Th17) cells, which play a crucial role in rheumatoid arthritis progression, are negatively correlated with the abundance of bacteria like Firmicutes. Changes in the gut microbiome also impact how patients respond to immunotherapy and other rheumatoid arthritis treatments.

Diet and rheumatoid arthritis

Diet may also play a role in the management of rheumatoid arthritis. For example, a high-fiber diet can suppress inflammation by increasing the number of beneficial immune cells, such as SCFAs-chain fatty acids, to promote gut health.

Incorporating omega-3 fatty acids in the diet can reduce inflammation by lowering the levels of inflammatory molecules such as tumor necrosis factor-α (TNF-α). A diet rich in vitamin E may also support gut health, reduce inflammation, and improve T-cell function.

In contrast, diets consisting of saturated fats and red meat can worsen rheumatoid arthritis symptoms, as both of these dietary components increase inflammation, whereas saturated fats have been shown to alter the gut microbiome.

The Mediterranean diet, which is rich in vegetables, fruits, fish, olive oil, legumes, and nuts and limits the intake of red meat and processed foods, has been recommended for managing rheumatoid arthritis. Vegan, vegetarian, and anti-inflammatory diets have also been found to be beneficial for lowering inflammation in the joints.

Conclusions

Gut dysbiosis contributes to the pathogenesis of rheumatoid arthritis by influencing immune responses through changes in intestinal permeability. Rheumatoid arthritis patients often exhibit reduced diversity in the gut microbiome, with an increased abundance of non-beneficial bacterial species.

Although dietary changes such as increased fiber intake and reduced consumption of red meat are beneficial, more research is needed to confirm the effectiveness of dietary interventions and the potential role of probiotics in managing rheumatoid arthritis.