Could Parkinson’s Start in the Nose?

For a long time, research into the origins of the condition has focused heavily on the gut-brain connection. However, a recent scientific review published in Current Opinion in Neurobiology suggests we should be looking higher up—specifically at the olfactory system, which is responsible for our sense of smell. A loss of smell is often one of the earliest signs of the condition, appearing years or even decades before movement symptoms like tremors begin. This new research explores the "olfactory-first" theory, which suggests that the proteins associated with the condition might actually start clumping together in the nose before travelling to the brain. Because the nose is constantly exposed to the environment, it may act as an entry point for toxins or pollutants that trigger these changes. The study highlights that the pathways connecting the nose to the brain are very direct. This unique connection might explain why the sense of smell is affected so early. By understanding how these proteins move from the nasal passages into the brain's emotional and memory centres, scientists hope to find new ways to intervene much earlier in the process. While the "gut-first" theory remains an important area of study, this research suggests that the condition may not have a single starting point for everyone. For some, the journey might begin in the digestive system, but for others, it could start in the nose. Recognising these different starting points is a vital step toward more personalised care and, eventually, finding ways to stop the progression before it reaches the parts of the brain that control movement.