Wednesday, July 13, 2011

The Case for the Connoisseurship of Smell

The sense of smell is least examined by those who can smell. Unlike seeing or hearing, its absence, known as anosmia, is as invisible as the act of scent perception itself. There are many reasons why one should pay attention to their sense of smell. Each one of us will naturally lose some of our ability to smell as we age which can affect appetite and signal the early onset of degenerative diseases like Parkinson’s or Alzheimer's disease.

It is important to exercise the sense of smell regularly, just as one would exercise to stay fit. One of the best ways to understand the sense of smell is to recognize what goes on when we taste food. Smell and taste work together to enrich the experience of eating. Becoming familiar with what happens when we can’t smell shines a light on the inner workings of taste. It also helps us understand the experience of those who suffer from taste disorders; a segment of the population that will grow as life expectancy continues to increase.

Nine out of ten people with smell dysfunction have a problem with taste. This is because the sense of smell is linked to the way we perceive flavor. Flavor perception takes place after we’ve swallowed our food and begin to exhale; a process called retronasal olfaction. Cats exercise their sense of smell in a similar way--with a twist. When they detect the odor of urine or estrous they will open up their mouth while they smell. This behavior is called the Flehmen response and also appears in horses. If you try smelling wine in this manner you will detect more of its nuances as taste which enriches the experience of flavor.

Taste receptors on our tongue detect sweet, sour, salty, bitter and umami (savory) characteristics in the food we eat. The temperature, texture and spiciness of food are detected by the trigeminal nerve. Cooling, burning, spiciness, fizziness (or tingling), pungency and astringency are trigeminal sensations we experience when we eat. Most people who are anosmic can experience tongue tastes and trigeminal effects, and enjoy food when more when these sensations are amplified. If you want to know what its like to have anosmia think about the time you had a bad cold and couldn’t taste the flavors in your food; that's what people with anosmia experience regularly.

The sense of smell is hard wired to the limbic system which is the part of the brain that processes memory and emotion. If you practice smell you are exercising memory; a fact worth considering if you want to stay ahead of cognitive decline at any age. Memories triggered by smell are stronger than those triggered by sight and sound which is what makes the sense of smell so powerful. If you practice describing what you smell you will develop a functional olfactory vocabulary while exercising your memory skills. What you perceive when you smell is related to your individual life experience so there are no wrong answers when it comes to describing what you are sensing.
How do you practice smelling? By making an effort to consciously experience smell and taste.Take a walk in nature and allow your senses to interact with everything around you. Can you smell the dirt under your feet? Has someone cut the grass nearby? Perhaps you can detect the smell of geosmin which is found in freshly turned earth. (Geosmin is related to a fragrant molecule in jasmine and is an aroma gardeners know well. It is also an ingredient in an award-winning perfume by Demeter called "Dirt".) If you are walking down city streets pay attention to what you smell block by block. The aroma of coffee shops, restaurants and food vendors powerfully define the experience of being in a neighborhood and are often the things we miss most when neighborhoods change.

The next step in practicing smell is finding the words to express what you are experiencing. This may seem tricky at first, but it’s easier than you think. Flavor wheels offer a starting point for learning how the combination of smell and taste is categorized. They provide guidance for foods like tea, coffee, chocolate, whiskey, beer, wine, cheese cognac and chocolate, and are easily found on the internet by googling the term “flavor wheel”. Taking cooking and wine tasting classes will allow you to use these tools, but you shouldn't neglect the place where you can learn the most; at home with family and friends. Next time you sit down to a meal consider sharing smell and taste experiences together. Your meal will be memorable and you'll also be keeping your mind fit.

Photo of Glass Petal Smoke's editor, at age two, investigating smells in her aunt's backyard.

YouTube video of the Flehmen response by Mr. Kyle Hayes. Copyright resides with the owner.

Image of "How Humans Experience the Taste of Food," is from The Umami Information Center. The copyright resides with the owner.