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The nose doesn't know: Life with no sense of smell

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From Starbucks to spoiled milk to freshly baked snickerdoodles, most of us take our sense of smell -- and the world's good, bad and ugly odors -- for granted. For people born with isolated congenital anosmia (ICA), though, the world smells as bland as a soggy soda cracker.

"I don't know what it is to smell," says Martin Angel, a 48-year-old urban planner from Santa Ana, Calif. "People try to describe it to me and I'm like, 'That's like trying to describe the sun to a blind man.'"

While Angel says he doesn't miss his sense of smell because "when you've never had something, there's nothing to miss," a new study published in the Public Library of Science's journal PLoS ONE has found that ICA can impact people in a number of ways, causing everything from enhanced social insecurity to an increased risk of household accidents.

"The sense of smell is one of the oldest sensory systems and provides a lot of important information influencing human behavior," says lead researcher Ilona Croy of the Smell and Taste Clinic at the University of Dresden Medical School in Germany. "Olfactory cues can transport emotional information, are critical for detecting edible food and help to prevent microbial threats. We were curious how people who are not able to smell lead their lives."

To find out, Croy and her colleagues interviewed 32 people with ICA along with 36 age-matched "controls" (people who could smell just fine). Questions ranged from how often they scorched food to how often they showered to the number of sexual partners they'd had in their lifetime. After tallying the results, researchers found people with ICA had a slight increase in social insecurity (i.e., they worried more about social situations and their own body odor), an increased risk for depressive symptoms and an increased risk for household accidents, such as eating spoiled food or burning clothes while ironing.

Julie Solo, a 45-year-old international health worker from Durham, N.C., who was born without a sense of smell, says she read about the study's findings but doesn't believe she suffers from either depressive symptoms or an increase in social anxiety.

"The only down side is worrying about not smelling a fire," she says. "Although I did once have a boyfriend who told me my feet smelled. He was just joking around, though."

On the other hand, ICA sufferer Carol Tedesco, a 53-year-old historic shipwreck professional from Key West, Florida, says some of the findings definitely ring true for her.

"I live in the tropics and I'm very active and I usually shower three times a day," she says. "I'm always concerned I might not be fresh. Plus I'm more dedicated to emptying the cat box and keeping it clean. You don't want someone to walk into your house and have it not smell good and not know it."

While approximately one-fifth of the population have an impaired sense of smell,  ICA affects only about 1 in 5,000 to 10,000 people, says Croy.

"In most ICA patients, there is no olfactory bulb, meaning they are missing the most significant part of the olfactory system in the brain," she says.

While people with ICA can still taste, Croy says they won't "perceive flavors as they are perceived via the sense of smell."

The inability to smell may also affect their sex life. The new study found people with ICA had about half the number of sexual partners as those with no smell impairment.

"This might be related to the enhanced social insecurity," says Croy. "However, it could also be that they are less responsive to odorous sexual stimuli."

While Croy's research points to the downfalls of ICA, those without a sense of smell quickly point to the upside of their condition.

"I can go into places that most people won't go into, like Porta-Potties," says Angel. "People will come out gagging, but I'm okay."

Solo, who does a lot of work in developing countries, says her inability to smell is actually a boon.

"A friend came to visit me once and we went to a slum in Nairobi where they were doing garbage cleanup," she says. "I guess the smell of a large garbage dump in a slum in Nairobi was pretty awful. My friend was dying, but I was just fine."

Tedesco, too, has found that her ICA has certain benefits.

"I can drive by where a skunk has been run over and not even notice," she says. "And my partner says I'm great to live with because I can't smell when he breaks wind. To me, it's just a sound."

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