Rheumatoid arthritis (RA) is a chronic autoimmune disorder that significantly impairs mobility and is one of the most prevalent autoimmune diseases worldwide. Extensive research has been conducted to elucidate its pathogenesis, genetic susceptibility, and neurological implications. This review provides a concise overview of RA, with particular emphasis on the gut-brain axis, dietary patterns, and interactions with brain-associated biomolecules, including neurotransmitters, sphingolipids, and glycerophospholipids. A deeper understanding of dynamic host-microbiome interactions may enable the development of personalized therapeutic strategies for RA and facilitate the identification of novel drug targets. In addition, metabolomics approaches are increasingly employed to uncover disease-specific biomarkers and metabolic alterations, contributing to a more precise understanding of RA pathogenesis and improving diagnostic accuracy. Collectively, these insights offer promising directions for future immunological research, with the potential to clarify underlying mechanisms of RA and enhance the quality of life for individuals affected by the disease.