Loss of smell is an early warning sign for 130+ diseases

One study claims that a poor sense of smell is linked to more than 130 diseases.

Diseases include dementia, Parkinson’s disease, chronic sinus problems and even fatal heart conditions.

The review, published in the journal Clinical Ear, Nose and Throat, suggests that olfactory disorders affect approximately 20 percent of the population, with even higher rates in men and people over 60.

This means that although loss of smell is more common than profound hearing loss or blindness, it has been far less studied.

The main culprit is chronic rhinosinusitis (CRS), which is sinus inflammation often caused by asthma, allergies, or cystic fibrosis.

Infections like flu and rhinovirus have long caused temporary odor problems, but COVID-19 has made it eight to ten times more common, researchers note.

Loss of smell may be one of the earliest detectable signs of neurodegenerative disease.

An important study from Nature Communications found that this may precede dementia, possibly because harmful proteins first begin to accumulate in the olfactory processing areas of the brain.

Another study showed that 90 percent of Parkinson’s patients experience loss of smell years before motor symptoms, sometimes up to five years before.

And the surprises keep coming. New data shows that poor olfactory function is linked to an increased risk of stroke and heart failure, even in previously healthy adults.

Beyond the prediction of illness, loss of smell disrupts daily life in ways that people rarely acknowledge.

Those affected are more vulnerable to gas leaks, fires, spoiled food and accidental poisoning.

Research also shows higher rates of eating disorders, depression, social isolation and relationship strain, with diets shifting toward sugar-rich, high-fat comfort foods that compensate for the dull taste.

Given the magnitude of the evidence, the expert panel calls for scent screening to be made routine and doctors to be trained to take it seriously.