A 2025 study conducted by researchers from the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy PAS, Wroclaw Medical University and the University of Connecticut shows that oral health, immune function and cognitive decline are closely interconnected in Alzheimer’s disease. The findings contribute to the growing concept of the mouth–brain axis, suggesting that even mild, chronic inflammation of the gums may have systemic consequences. The study demonstrated that patients with Alzheimer’s disease not only present worse oral hygiene and increased gingival inflammation, but also exhibit significant dysregulation of the immune system, characterized by reduced baseline activity alongside an exaggerated response to bacterial stimulation. This imbalance may reflect both immune exhaustion and hyperreactivity, which together can contribute to harmful inflammatory processes. Importantly, the severity of gingival inflammation was associated with lower cognitive test scores, regardless of age or sex, indicating a direct relationship between oral health and cognitive performance. The proposed mechanism suggests that chronic periodontal inflammation places a continuous burden on the immune system, leading to its dysfunction and facilitating the penetration of inflammatory signals into the brain, where they may enhance neuroinflammation and accelerate disease progression. The study also highlights a practical challenge, as individuals with Alzheimer’s disease tend to neglect daily oral hygiene, which further exacerbates the problem. These results underline that oral health should be considered an integral part of systemic health and dementia care, and that simple preventive measures, such as maintaining proper oral hygiene and supporting patients through caregiver involvement, may have meaningful implications for brain health.
