Joy Milne, a 74-year-old retired nurse from Perth, Scotland, has an extraordinary ability: she can smell Parkinson's disease. Her story began when she noticed her husband Les had developed a new musky odour years before he was diagnosed with the neurodegenerative condition. In 2012, she approached neuroscientist Tilo Kunath at the University of Edinburgh, who initially dismissed her claim but later tested it alongside analytical chemist Perdita Barran.
In a study, Milne correctly identified six T-shirts worn by Parkinson's patients from a set of 12. Remarkably, she also flagged one person who was diagnosed with the disease less than a year later, effectively pre-diagnosing the condition. Barran, now at the University of Manchester, described the result as 'kind of amazing'. Milne has hereditary hyperosmia, a trait that gives her a sense of smell far more sensitive than average, making her a 'super-smeller'.
Body odour can signal various health issues. People with diabetes experiencing hypoglycaemia may emit a fruity or 'rotten apples' aroma due to ketones. Liver disease can cause a musty or sulphurous smell in breath or urine, while kidney disease may produce an ammonia-like or fishy odour. Infectious diseases also have characteristic scents: sweet-smelling faeces can indicate cholera or C. diff infection, and tuberculosis can make breath smell like stale beer and skin like wet cardboard and brine.
Scientists are now developing technologies to detect these 'whiffy biomarkers' for early diagnosis. Andreas Mershin, co-founder of RealNose.ai, notes that dogs can already detect prostate cancer by scent, and a robotic nose could replace invasive tests. While most diseases require trained animals or devices, Milne's unique ability has opened new avenues for research into scent-based diagnostics.
