Have you ever wondered why you can’t taste when you’re sick? Sure, you may know that smelling and tasting are related, that if your nose is stuffed it makes it hard to smell and therefore taste, but do you know why? What does this mean for people with anosmia (1) like myself?
Taste and smell are an iconic duo. Without one, it’s hard to have the other and that is because tasting and smelling are a complex, connected system.
The process of smelling starts off with dissolved particles of whatever we’re smelling floating into the nostrils and landing in the mucus. Underneath our mucus, lies our olfactory receptor neurons that detect odors and send the information to the olfactory bulbs at the very back of our nose. These bulbs are connected to the brain so the brain can interpret the smell and connect it to memories (2).
The process of tasting, however, is more direct. On our tongue, cheeks, and roof of the mouth, we have thousands of taste buds with up to one hundred taste receptors in each bud. These receptors are used to sense five key flavors: bitter, sour, umami (3) sweet, and salty. The detected flavor is then immediately sent to the brain to be interpreted (4).
Taste and smell are considered chemosensational (5). Both of these senses have their own receptors that allow us to sense our environment through receptors on our nose, throat, and mouth. These things go into the total experience of eating. When you’re sick or have anosmia, your brain is only getting half the picture. The smell isn’t contributing to how your brain interprets the taste and has to go fully on what the taste buds receive. The second half of the equation is not accessed (6).
For people with anosmia, this means that half of the flavor is potentially lost. Their brains are not able to identify and distinguish between tastes because the brain does not know how to interpret what is being tasted. People who are sick get a small “taste” of not having the full experience and often eat far saltier, bitter, or brothy foods so they can actually taste the food (7).
The odd correlation between taste and smell shows that the brain plays a key role in how our senses work. Because taste and smell are so entwined with each other, the brain has a hard time interpreting flavor when one is missing. Next time you eat, try holding your nose and blocking the smell, and taste the difference. That’s one way to actually experience a taste/smell phenomena (without getting sick or suffering an injury!)
(1) Anosmia is the loss of the sense of smell, either total or partial, from illness, blockage, or disability.
(2) Rodriguez-Gil, Gloria. “The Sense of Smell: A Powerful Sense.” Selected Assessments That Are Used For Young Children Who Are Visually Impaired, 2005, http://www.tsbvi.edu/seehear/summer05/smell.htm.
(3) Umami is the Japanese word for “savory”
(4) Bradbury, Jane. “Taste Perception: Cracking the Code.” PLoS Biology, vol. 2, no. 3, 2004, doi:10.1371/journal.pbio.0020064.
(5) Relating to our chemical sensing system.
(6) “Taste and Smell.” Brain Facts, 1 Apr. 2012, http://www.brainfacts.org/Thinking-Sensing-and-Behaving/Taste/2012/Taste-and-Smell.
(7) Communications. “Smell & Taste.” American Academy of Otolaryngology-Head and Neck Surgery, 3 Jan. 2018, http://www.entnet.org//content/smell-taste.