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Researchers say loss of smell, taste from COVID-19 could affect appetite, mental health

Click to play video: 'Quality of life can be impacted by loss of smell and taste' Quality of life can be impacted by loss of smell and taste
Loss of smell and taste has become a telltale symptom of COVID-19. Now, doctors say that those who still have not yet regained their sense of smell can see their quality of life and mental health suffer. Julia Wong reports – Feb 5, 2021

A unique symptom of COVID-19 is the loss of smell and taste, and while most patients are able to quickly regain those senses, some do not and researchers say there can be impacts on quality of life.

Peter Andrews, a consultant rhinologist in London, England, said this particular symptom of COVID-19 has cast smell into the limelight.

“Sense of smell was always termed the Cinderella sense. Often ignored. Not particularly noticed but now it’s very much at the forefront of what’s going on.”

Dr. Leigh Sowerby, a professor in the Department of Otolaryngology – Head and Neck Surgery at Western University, was a part of a global effort in April 2020 to identify the prevalence of the loss of smell.

READ MORE: London, Ont., researchers studying loss of smell in COVID-19 patients as part of global initiative

Results from more than 100,000 surveys show that approximately 50 per cent of COVID-19 patients experience loss of smell; the majority of patients will have a return to normal within one to two weeks, but Sowerby said there’s between five and 10 per cent who suffer a decrease or a complete loss of smell after one to two months.

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He notes the consequences could include being unable to identify harm, citing a family in Texas where almost all members had contracted COVID-19, lost their sense of smell and were unable to smell smoke in their house. One family member who still had the sense of smell was able to get the family to safety.

READ MORE: Healthy teen saves family with COVID-19 who couldn’t smell house fire

“That just belies the importance of smell in identifying things like smoke, if you think about natural gas leaks, that ability to smell that rotten egg – those are all really important things from a safety perspective,” he said.

Sowerby said other repercussions include the ability to know when food has expired and the loss of appetite.

“When we chew, those odourants go up behind our palette and then we smell them so [it’s] why a pinot noir tastes different than a cabernet sauvignon. That’s really about smell,” he said.
“I had one patient [who had] this loss of smell on the order of six months now. They’re just not interested in eating so they’ve had a 20-pound weight loss because they’re not interested.”
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Andrews further said there is some evidence that loss of smell impacts quality of life.

“Without it, people are depressed. Without the sense of smell, people are unable to socialize as much, enjoy their meals, enjoy all the interactions we do as human beings.”

Christina Herbers, 43, of St. Albert, was diagnosed with COVID-19 in early December. Her first symptom was a raw throat then, a couple days later, she lost her senses of taste and smell.

“My first indication was drinking my coffee and it tasted like nothing, like water. I thought, ‘Oh that’s weird, my coffee machine’s not working. I’ll make another one’ and no, I couldn’t taste the coffee, couldn’t taste my oatmeal – pretty much completely gone,” she said.

Herbers was hopeful her sense of taste and smell would return by Christmas but it did not. The self-described foodie said two months later, those senses have not yet returned and she admits that it has been difficult.

“It’s like you’re eating your dinner and it literally tastes like cardboard. There’s no flavour. There’s no joy with the meal. It sucks.”

Herbers said she has lost her appetite and five pounds as a result.

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Read more: ‘I’m scared’: Coronavirus long-haulers claim they’ve been left to fend for themselves

As for how the virus may be causing this unique symptom, Andrews said SARS-CoV-2 binds to receptors in the body’s respiratory system.

“These receptors are very much prevalent around the supporting cells of the olfactory system. These obviously are damaged and as a consequence, the supporting cells then can’t ensure the olfactory neurons are alive and that’s why the sense of smell is reduced,” he said.

At this point, it isn’t clear how long smell loss could last.

Herbers said the ordeal has been tough psychologically, saying she did not realize how much pleasure she got out of drinking coffee.

While she is grateful she did not end up in hospital as a result, Herbers said it is a waiting game for her senses to return.

What can people do?

Andrews works in a smell clinic at the Royal National ENT and Eastman Dental Hospitals in London, England. There, patients are seen by specialist physicians who measure their sense of smell and offer treatment protocols to help with its loss.

Andrews said those can range from watching and waiting to see if smell will come back, steroid treatments and olfactory training.

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Both researchers said COVID-19 patients can retrain their sense of smell by smelling a variety of scents, such as clove, cinnamon, lemon and other spices.

Read more: ‘We know this is real’: New clinics for coronavirus long-haulers crop up in U.S.

Sowerby said doing this a couple of times a day over a period of months can help. He also suggests ensuring there are proper and working smoke and natural gas detectors in people’s homes.

As for how to enjoy food again, Sowerby suggests focusing on other things, like presentation.

“Using some parsley on top of your paella – you have the visual enjoyment of that food. Adding spice, adding salt, pepper, that sort of thing where you have that stimulation in the oral cavity – you may not necessarily have the full flavour but you can improve the enjoyment.”

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