There is an episode of Seinfeld in which Elaine explains that she is “hard of smelling.” We laugh. That’s ridiculous. How can one be hard of smelling? But, truth is much stranger than fiction. You can be hard of smelling. In fact, problems with sense of smell affect up to 20 percent of Americans and reduced, lost or distorted smell can significantly lower quality of life.
Dr. Donald Leopold, otolaryngologist and rhinologist at the University of Vermont Medical Center, explains the science of smell. He sees patients from around the world who have a range of smell disorders.
What exactly is the sense of smell? How does it work?
The sense of smell is the human ability to appreciate chemicals in the environment. These chemicals, like cinnamon or rose, interact with the receptors in the nose. They enter the nostril through the front, or by wafting up behind your palate to the back to your nose. The latter happens when you are eating. The sense of smell is primitive as far as human development is concerned. That makes smelling a largely neurological process: once a molecule is identified in your nose by scent receptors, they send a message to the nerves of your sense of smell system into your brain where that message interacts with different areas of the brain and may affect functions like breathing, or emotions.
What is a smell disorder?
There are two main areas of olfactory, or sense of smell issues: either your sense of smell fails, or it is distorted. There is hyposmia (reduced smelling ability), anosmia (the inability to perceive odor), parosmia (when “regular” smells are distorted), and phantosmia (when one perceives smells with no stimulus).
Some conditions may cause a “conductive” smell disorder such as chronic sinus problems, allergies, or nasal polyps that clog the nasal airways. There are other conditions that may cause nerve losses. One of these occurs during the common cold, and we call it post-upper respiratory infection smell loss. For example, a healthy 35-year old woman catches a cold, but four days later finds she can’t smell anything. Her sense of smell may be gone for the rest of her life. Head trauma may also cause smell issues – typically, on the front or back of your head. This also involves nerve damage – and, it doesn’t take much. I saw a young man who bumped his head on a wall and the next morning could not smell his aftershave. It may be relatively minor trauma that can affect your sense of smell.
How does our sense of smell change as we age?
Our sense of smell weakens as we age due to a loss of nerve cells in the nose. This is often a problem in nursing homes: residents complain that the food has a terrible flavor. Then, a family member visits and finds that the food is fine. The resident is experiencing the problems that occur with loss of sense of smell as we age. Things may not smell the same, and flavor is greatly reduced.
How do you help patients with smell disorders?
The first step is to define the problem. A patient comes in and tells me that she can’t smell or taste. I need to find out what is really going on. We do taste testing and smell testing in the clinic. We will also use an endoscope to examine the nose to explore the pathways toward the receptors. The upper nose may be clogged with polyps, inflammation or infection such that we can improve them with medical therapy, rinses, oral steroid pills, or surgery. There is an ability to improve those patients.
How does a loss of sense of smell affect quality of life?
People experience classic grief: you have lost something and you mourn it. That said, it is quite variable, depending on how important your sense of smell is to you. For people who rely upon their nose for their careers – restaurateurs, perfumers, and coffee experts – it can mean a loss of livelihood. I have seen a number of chefs who now have to pursue a different career because they have lost this critical function. That is life changing. Some patients – like those who have phantosmia – may become depressed or suicidal. Imagine if all you smelled all day was burning rubber? That is what these patients are dealing with. We are currently doing research to further our understanding of this disorder.
Is it possible to improve your sense of smell?
What you have is what you get – but, as in any special sense, you can use what you have better. Think of the musician honing her craft to pick up on the subtleties of an orchestral work, or the hunter attuning himself to a bird’s call. Similarly, people with a good sense of smell may identify certain parts of a salad dressing, or pick up on the scent of a smoker. Perfumers do this. They train themselves to pick up on certain scents – mostly good ones!
What role does the sense of smell play in enjoying food?
Sense of smell plays a large role in how we experience foods and beverages. In fact, eighty percent of how we perceive flavor is affected by smell, not taste. Taste is only salt, sweet, bitter, umami (savory), and sour and that is all on your tongue. If you lick a pink ice cream cone, your sense of taste will tell you it’s sweet, your tongue will tell you its cold and smooth, but your sense of smell will tell you that it is strawberry-flavored. I have had people whose sense of smell is altered tell me that pizza has the flavor of salty cardboard. Just pinch your nose the next time you eat and tell me what flavors you perceive.
There are a lot of smell-related phrases and sayings. Is there any truth to the phrase “wake up and smell the coffee”? Does it really help us wake up?
The smell of coffee does not do anything to stimulate you, except for the mental association you make with it, just like any nerve stimulation. The other thing smell can do is bring back memories. If I give you the smell of freshly baked bread it may return you to your childhood kitchen where your mother baked bread, or if I give you the fragrance that your first lover used you may recall that pleasant, or unpleasant, interaction in vivid detail. Your body locks away these smells and they are hugely important. It is part of our personal identity.
Donald Leopold, MD, is an otolaryngologist and rhinologist at the University of Vermont Medical Center. He is also a Professor at the Larner College of Medicine at UVM.