About a quarter of the human brain’s mass is devoted to processing information from the five senses. Given that the brain plays such a central role in health, it’s not surprising that the five senses are closely tied to well-being.
But beyond merely proving those connections exist, researchers have recently started to explore ways to purposely manipulate them for people’s benefit. “Interventions based on what we see, feel, and even taste can have a seemingly dramatic effect on health,“ says Charles Spence, an Oxford University PhD researcher who runs a lab dedicated to studying the role that perception plays in behavior and health. “They can reduce pain, speed recovery from illness, and much more.”
Smell plays an important role in overall health. “Smell is associated with neurodegeneration, heart disease, and early demise, among other problems,” says Richard Doty, a PhD smell researcher who directs the Smell and Taste Center at the University of Pennsylvania’s medical school. Doty notes that multiple studies have shown that people whose sense of smell becomes heavily dulled over time are at a higher risk for those diseases. In the case of Alzheimer’s, clumps of protein known as plaques that build up in the brains of people who suffer from the condition form in the part of the brain responsible for smell, possibly explaining the association.
Paying more attention to smell could provide a critical early tipoff to brewing problems. A decline in your sense of smell is as good a predictor of Alzheimer’s as genetic tests, according to Doty. To test how useful that relationship can be, in 2020, Doty will send 80,000 people a smell test he developed as part of a study funded by the Michael J. Fox Foundation. People whose results on the test indicate that they’re losing their sense of smell can be tagged for brain imaging and other advanced tests for neurodegeneration. If the effort helps catch problems early — when diseases of the brain may be more treatable — promoting smell awareness could become a major public health initiative, says Doty.