Discuss as:

Sniff test: Living without a sense of smell

When Bridget Lewis began to lose her sense of smell, her friends and family thought she couldn't be serious.

"Everyone thought I was joking," says Lewis, who's 42 and lives in Arlington, Texas. "My mom even had fun with it, and 'tested' me. She asked me to hold out my tongue and had my little sister grab things from the kitchen, like Tabasco sauce and lemon juice and they squeezed drops of it on my tongue! When they saw I had no reaction, they believed me."

In Lewis's case, a severe bronchial infection stole her sense of smell in 2002; nine years later, it's only partially returned. Most of us have experienced a temporarily diminished sense of smell -- it's part of the super fun side effects of a cold, along with the dripping nose and general malaise. But before it happened to her, Lewis says she didn't even realize a long term loss of smell was even possible -- there is blindness, and deafness, but many people aren't familiar with the word for a lost sense of smell: anosmia.

"It's not as dehabilitating [as losing other senses]," says Dr. Beverly Cowart of the Monell Chemical Senses Center. "But I think people find it hard to relate to; I think people don't appreciate how much they use their sense of smell."

An estimated 1 to 2 percent of people in North America say they have a smell disorder, according to government figures. It's more common in men than in women, and it's much more common in older people, occurring in nearly 25 percent of men aged 60 to 69 and 11 percent of women in that age range, according to the National Institutes of Health.

High inside your nose is a grouping of cells called olfactory sensory neurons. These neurons each possess an odor receptor, which picks up on the tiny molecules released by things like a just-peeled orange, a bag of microwaved popcorn or your coworker's tuna fish lunch. The neurons then pass the information to your brain, which interprets the smell.

As Cowart explains, there are a few common ways to lose your sense of smell: a chronic nasal sinus disease, a viral infection, inhaling something toxic or a head injury. Unlike most nerves, the brain's olfactory nerve fibers are continuously replaced, "so occasionally people can gradually regain their sense of smell as new fibers grow in." And some people are born without the ability to smell.

Lacking a sense of smell can be dangerous -- anosmics wouldn't notice a gas leak, or the smell of smoke. Personal hygiene is a big worry for some. "The biggest effect is on food-flavor perception," Cowart says. "It actually creates social difficulties for people. Sometimes, people become more isolated; they don't go out as much."

Smelly stuff reaches the olfactory neurons in one of two ways: either through your nostrils, or through a pathway connecting the roof of your throat to your nose. If that second passageway is blocked, we're unable to pick up on the odors -- and, consequently, the flavors -- emitted by food.

One rainy day four years ago while Lewis was pregnant, she remembers bursting into tears over her anosmia."I was sad and I think depressed because I realized I couldn't smell the rain ... and realized I wouldn't be able to smell the scent of my newborn," Lewis remembers. "Horrible day."

On the upside, potentially smelly tasks like cleaning out the fridge don't bother her at all -- but she adds that she tends to go overboard. "I have always been scared that I could make our daughter sick — if I even suspect something has been in the fridge for too long, I throw it out.  I've also burned many pots and foods in the oven because as they cooked, I couldn't smell them!"

Have you or a family member lost the ability to smell? How has it impacted your life?

You can find The Body Odd on Twitter and Facebook, and follow Melissa Dahl @melissadahl.