Healthy gut holds key to fight against auto-immune diseases

Lucknow: The pathogenesis of auto-immune diseases (ADs) is attributed not only to genetic vulnerabilities but also to environmental factors. Among these factors, qualitatively and/or quantitatively altered gut microbiota has garnered immense attention.

Human gastrointestinal tract hosts a complex ecosystem of approximately 300-500 bacterial species, encompassing nearly 2 million genes (microbiome). The number of bacteria within the human gut is roughly 10 times more than that of all the cells in the human body. The cumulative bacterial genomic content is immensely greater than the human genome.

Research-based evidence suggests that disturbed gut microbiota contribute to pathogenesis of auto-immune disorders, such as rheumatoid arthritis and irritable bowel syndrome (IBS).

Studies show that patients with rheumatoid arthritis exhibit suppressed gut microbial diversity, which correlates with autoantibody levels and disease duration. As per the European study, dysbiosis has been observed to precede the development of arthritis.

Patients with rheumatoid arthritis have an increased abundance of Prevotella species, including Prevotella copri and Collinsella. Collinsella Aerofaciens has been linked to increased gut permeability and expression of IL-17A, a key cytokine involved in pathogenesis of rheumatoid arthritis. This suggests Collinsella could be a biomarker for identifying arthritogenic bacteria in the human gut.

Conversely, beneficial bacteria like Faecalibacterium are decreased in RA patients.

Microbial dysbiosis in the gut is believed to play a central role in pathogenesis of IBS. Recent studies have revealed distinct differences in the gut microbiota between patients with IBS and healthy individuals. IBS is characterised by increased Firmicutes, including bacteria capable of forming resistant endospores.

Additionally, there is a marked reduction in beneficial microbes like Bifidobacterium (regardless of IBS subtypes) and Faecalibacterium species in IBS patients.

Firmicutes-to-Bacteroidetes ratio (F/B ratio) is often used to assess gut microbiome balance, and higher ratio indicates microbial imbalance. Harmful bacteria like Escherichia, Shigella, Campylobacter, and Salmonella are significantly elevated inIBS patients. By-products produced by these bacteria can contribute to typical irritable bowel syndrome symptoms, including abdominal pain, bloating, and diarrhea.

Symptoms of auto-immune diseases can be achieved through dietary modifications, such as restricting fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) derived from fast food. Foods that promote production of short-chain fatty acids such as dietary fibers and resistant starch, are recommended to create a gut environment that suppresses auto-immune responses.

A predominantly unprocessed vegetarian diet can help prevent flare-ups of auto-immune diseases. Complemented with dietary changes, regular exercise, good sleep, and stress reduction can prevent auto-immune diseases.
Understanding and addressing the role of gut microbiota in ADs opens new avenues for personalised interventions to restore microbial balance and improve overall health.