Neurodegeneration and Environmental Health: Emerging Role of Polluting Metals in Alzheimer's Disease (AD): A Narrative Review

Alzheimer’s disease (AD) is a complex neurodegenerative condition characterized by progressive cognitive decline and neuronal dysfunction. In addition to the known, genetic factors, such as the APOE ε4 allele, growing evidence points to the influence of environmental elements, particularly polluting metals and air pollution, in the development and progression of AD. This review explores how metals like iron (Fe), copper (Cu), and manganese (Mn), when present in excess or dysregulated, contribute to oxidative stress, neuroinflammation, mitochondrial damage, and pathological protein aggregation in the brain. Moreover, air pollution, especially exposure to particulate matter, has been associated with higher AD risk. The role of gut dysbiosis and systemic inflammation is also discussed as a potential link between environmental exposure and neurodegeneration. This synthesis of current literature highlights the importance of recognizing environmental metals as modifiable risk factors for AD and the urgent need to incorporate environmental health considerations into dementia prevention strategies.