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NIH MedlinePlus the Magazine, Trusted Health Information from the National Institutes of Health


Medical Mystery: Losing the sense of smell

Suzie Thomas

Suzie Thomas suffered a head trauma as a teenager that took away her sense of smell.
Photo courtesy of Malone University

Imagine, if you can, a world without scent. Of not being able to "wake up and smell the coffee."

Welcome to the odor-free world of Suzie Thomas, 54, a Canton, Ohio, public relations executive. She suspects she lost her sense of smell after breaking her nose as a cheerleader, years ago. The complete inability to smell, known as anosmia, is generally rare, but can happen in people who have experienced head trauma. More common is a gradual diminishing of the senses of smell and taste with age.

Although it may seem that smell and taste rank as second-tier senses behind seeing, hearing, and touching, their loss can be both depressing and dangerous. Thomas recalls being in her kitchen with her back to the stove, unaware that a pot had caught fire. She did not realize what was happening until her sons burst into the kitchen yelling, "What's burning?"

Our sense of smell is also key to perceiving flavor and taste. Working alone, taste buds can only detect five flavors: salty, sweet, bitter, sour, and savory. Smell adds a practically limitless variety and subtlety to the world of flavors.

The sense of smell often diminishes with age—in one clinical study, 40 percent of men and 20 percent of women between ages 70 and 79 had measurable smell impairments.

Over the past 20 years, researchers have made great strides in understanding our sense of smell. For example, they have discovered how odor receptors working alone or in combination allow us to detect 10,000 different odors. They have also discovered how the odor receptors communicate with the brain to alert us to the presence of odors.

NIDCD is supporting research aimed at better understanding how the senses of smell and taste work. Of all the senses, smell and taste hold the most medical mystery. Researchers hope that new knowledge might eventually point the way to methods and treatments to preserve and restore the senses of smell and taste.

Fall 2008 Issue: Volume 3 Number 4 Page 17