No one worries about losing their ability to smell, at least not like they might about sight or hearing. Nonetheless, your olfactory sense (smell) is important in more ways than just delivering the pleasure of fragrance or helping the ability to enjoy flavours.
People have a relatively weak sense of smell in comparison to most animals. Among humans, women have far more olfactory receptors in the brain which means they have a better sense of smell. And did you know we have a dominant nostril? It’s usually on the same side as our dominant hand. Odours can also affect the release of certain brain chemicals which can produce relaxation or excitement, alter mood or even reduce pain, but this varies person-to-person.
But how does smell work? Microscopic molecules released into the air stimulate specialized olfactory sensory cells high inside the nose. These are connected to the area of the brain that handles smell and tells you what you just smelled. If the channel to olfactory cells is blocked such as when your nose is stuffed up, odours cannot reach the sensory cells and not only do you not smell it, but your ability to enjoy a food’s flavour is also lost.
While complete olfactory failure is very rare, less severe impairment is not uncommon, even if we exclude colds and congestion. In fact, after age 40 we gradually lose the ability and sensitivity of smell. Olfactory problems can also signal poor health or other problems. Smell disorders can arise for many additional reasons: sinus and other upper respiratory infections, smoking, growths in the nasal cavities, head injury, hormonal disturbances, dental problems, exposure to certain chemicals such as insecticides and solvents, and numerous medications, including some common antibiotics and antihistamines.
Losing the ability to smell can seem minor, especially when considered against the other senses, but there are important factors to consider. For example, when a person’s sense of smell is impaired, they may change their eating habits, eating too little or too much, or as it loses flavour, they might add too much salt to improve the taste.
Problems with smell may be a sign of other serious health conditions. A smell disorder can be an early sign of Parkinson’s disease, Alzheimer’s disease or multiple sclerosis. It can also be related to other medical conditions, such as obesity, diabetes, hypertension and malnutrition. A study released in October 2014 examined 3,000 older adults and their ability to smell. It found that those who were unable to detect scents such as rose, orange and peppermint were more than three times as likely to die in the next five years, versus those with a sharp sense of smell. This is after controlling for other factors such as age.
These finding do not mean we should all be scared if we don’t smell something. Rather, we should recognize that a loss of olfactory ability can be a flag for other health problems. In other words, we need to stop and smell the roses (you knew we’d have to say that, right?) and if you can’t smell them, see your doctor about it.
Editor’s note: Dr. Paul Martiquet is the medical health officer for rural Vancouver Coastal Health including Powell River, the Sunshine Coast, Sea-to-Sky, Bella Bella and Bella Coola.
