Emerging research suggests that early signs of Alzheimer's disease may be getting to the brain via the nose, with warning signs potentially present long before memory problems appear.
Alzheimer's is a progressive condition and the most common cause of dementia in the UK. The Alzheimer's Society claims that there are currently estimated to be 982,000 people with dementia in the UK, with the number expected to pass 1.4 million by 2040.
The theory that Alzheimer's could start in the nose
Professor Hannah Fry has talked about an emerging theory that Alzheimer's disease may begin in the nose. She discusses research that claims warning signs are potentially there long before memory problems appear.
The mathematician and broadcaster, whose father died with the condition in 2025, explained that the nose is one of the very few pathways into the brain from the outside world. While this access gives most people a sense of smell, experts have found it could open a pathway for infection and disease.
Studies in mice and pollution exposure
Studies in mice found that a bacterial infection introduced through the nose travelled to the brain within 72 hours, triggering the same inflammation and plaques seen in Alzheimer's. Other research found metal particles and similar changes in the brains of dogs and people exposed to heavy pollution.
