The Surprising Link Between Your Sense of Smell and Brain Health

Your grandma’s brownies, the scent of rain on a pine forest, a whiff of cardamom — smells can be powerful time machines, unlocking memories almost like magic and transporting you to specific moments more vividly than vision or hearing.

But just like vision and hearing, our sense of smell diminishes with age (and as a result of infections like Covid, smoking and pollution). About 11 percent of Americans in their 50s experience trouble smelling; that number rises to 39 percent for those over 80.

When our noses lose their sharpness, our mental health often suffers too. A diminished sense of smell is associated with worsening memory, cognition and overall well-being — as well as dementia and depression.

“Our brains need a lot of olfactory stimulation in order to maintain their health,” said Michael Leon, a professor emeritus of neurobiology at the University of California, Irvine.

Fortunately, a diminished sense of smell may be reversible, perhaps by something as simple as spending some time with your spice rack.

Why smell is so important in the brain

Scientists have long recognized that a reduced ability to detect and identify scents may be an early symptom of conditions such as depression, dementia and Parkinson’s disease. You may notice, for example, that your favorite wine has somehow lost its nose, or fail to notice that food is spoiling in your fridge, said Sarah Banks, a neuropsychologist at the University of California, San Diego. For many people, troubles with smell are among the first signs of Alzheimer’s, she added.