Anosmia: lacking a fifth sense
Pine trees. Peppermint cocoa. Gingerbread. Mulled cider. To me, the holidays wouldn’t be the same without these aromas. Every year I look forward to browsing the candle aisle at Target for far too long, looking for the perfect combination of scents to envelop my apartment. But for some, this is not even possible. Anosmiacs don’t associate memories with smells because, well, they can’t smell.
Anosmia is the inability to perceive odor and people with this disorder, like my friend Brittany, don’t have a sense of smell. There isn’t just one type of anosmiac though. Some are born without this fifth sense, which is called congenital anosmia, and some people lose the sense during their lifetime from head trauma or even Alzheimer’s disease.
Earlier this month, researchers at Columbia University were able to manipulate what mice tasted by turning on and off certain taste centers in their brains. They were able to make the mice think the water they were drinking was bitter when it was just plain drinking water. They showed that taste is hard-wired into the brain, and that there are specific regions that correspond to certain tastes, like sweet and bitter, making taste independent of learning or experience. This is different from sense of smell because odors don’t have any innate meaning until you associate them with an experience. One smell could be great to me, and be horrible for someone else.
Most people know that smell is very related to taste. When you eat, you chew your food and this breaks up the particles, sends the vapors to the back of your mouth and up your nose, making your brain relate the taste to the smell of the food. This is why when you have a cold, it seems like you can barely taste anything. But is that how it is for anosmiacs all the time?
Not so according to anosmia bloggers and my friend Brittany. She has congenital anosmia, but her olfactory system, the functional system you use to smell, is in tact. According to another blogger on Mental Floss, she can’t tell the difference between sage, basil and oregano, but remarks that while another anosmiac can’t tell the difference between cranberry juice and orange juice, she certainly can.
Because of all of these differences, there’s not one treatment for anosmia, and if someone’s olfactory system is in tact, it points to a much smaller problem—in size at least. The Monell Center in Philadelphia is a taste and smell research center and they have linked loss of smell in mice to loss of a specific protein, Ggamma13. However, in order to connect this discovery to human cases of anosmia, each patient would need to be tested for the missing protein and even if those tests are conclusive, research has not yet led to a treatment for these patients.
Brittany still craves the bison Bolognese from The Abbey in Washington Square, but can’t smell the candle she bought me for Christmas. Smell and taste have always been linked in my mind, but research is showing us they are wired differently in the brain. There is still so much unknown about the brain, but it seems like anosmiacs could definitely help us understand sense of smell, and perhaps taste, better. For now, I will keep baking holiday treats in hopes that my friend can at least enjoy eating them!