Until March, when everything started to taste like cardboard, Katherine Hansen had such a keen sense of smell that she could recreate almost any dish in a restaurant at home without the recipe, just by remembering the smells and flavors.
Then came the coronavirus. One of Hansen’s first symptoms was loss of smell and taste. Hansen still can’t taste the food and says he can’t even tolerate the chewing. Now he mainly lives on soups and smoothies.
“I’m like someone who loses sight as an adult,” says Hansen, a real estate agent who lives outside of Seattle. “They know what things should look like. I know what it must taste like, but I can’t prove anything. “
A decreased sense of smell called anosmia has emerged as one of the telltale symptoms of COVID-19, the disease caused by the coronavirus. It is the first symptom for some patients, and sometimes the only one. Often accompanied by an inability to taste, anosmia occurs abruptly and dramatically in these patients, almost as if a switch had been flipped.
Most regain their sense of smell and taste after recovery, usually within weeks. But in a minority of patients, such as Hansen, the loss persists, and doctors don’t know when or if they will regain these senses.
Scientists know little about how the virus causes persistent anosmia or how to cure it. However, cases are increasing as the coronavirus spreads around the world, and some experts fear that the pandemic could leave a large number of people with permanent loss of smell and taste. This possibility has sparked an urgent struggle among researchers to learn more about why patients lose these essential senses and how they can help them.
“Many people have been doing olfactory research for decades and have received little attention,” said Dolores Malaspina, professor of psychiatry, neuroscience, genetics and genomics at the Icahn School of Medicine at Mount Sinai in New York. “COVID turns that field upside down.”
Smell is closely linked to both taste and appetite, and anosmia often robs people of the pleasure of eating. But the sudden absence can also have a major impact on mood and quality of life.
Studies have linked anosmia with social isolation and anhedonia, the inability to feel pleasure, as well as a strange sense of detachment and isolation. Memories and emotions are intrinsically linked to smell, and the olfactory system plays an important, but largely unrecognized, role in emotional well-being, said Sandeep Robert Datta, associate professor of neurobiology at Harvard Medical School.
“The smell is not something we pay much attention to until it disappears,” said Pamela Dalton, who studies the link between smell and cognition and emotions at the Monell Center for Chemical Senses in Philadelphia. ‘Then people notice, and it’s pretty painful. Nothing is the same “.
British scientists studied the experiences of 9,000 COVID-19 patients who joined a Facebook support group founded by the charity group AbScent between March 24 and September 30. Many members said that they had lost not only the pleasure of eating, but also of socializing. The loss had weakened their bonds with other people, affected intimate relationships, and left them isolated, even separated from reality.
Loss of smell is a risk factor for anxiety and depression, so the implications of generalized anosmia are of great concern to mental health experts. Malaspina and other researchers have found that olfactory dysfunction often precedes social deficits in schizophrenia and social isolation, even in healthy people.
“From a public health point of view, this is very important,” said Datta. “If the number of people with COVID is considered internationally, even though only ten percent have a longer odor loss, we are talking about potentially millions of people.”
The most immediate effects can be nutritional value. People with anosmia can still taste the basic flavors: salty, sour, sweet, bitter and umami. But taste buds are relatively rough masters. Smell makes taste perception more complex due to hundreds of smell receptors that the brain signals.
Many people who cannot smell lose their appetites, putting them at risk for nutritional deficiencies and unwanted weight loss. Kara VanGuilder, who lives in Brookline, Massachusetts, said she had lost 20 pounds since March, when her sense of smell faded.
Fragrances also serve as a primitive alarm system warning people of dangers in our environment, such as fire or gas leaks. A reduced sense of smell in old age is one of the reasons older people are more prone to accidents such as fires caused by leaving burnt food on the stove.
People are constantly scanning their environment for smells that signal change and possible harm, although the process is not always conscious, said Dalton of the Monell Center for Chemical Senses.
The scent alerts the brain to the mundane, such as dirty laundry, and the risky, such as spoiled food. Without this form of detection, “people get anxious about things,” Dalton said.
What’s worse is that some COVID-19 survivors are haunted by phantom smells that are unpleasant and often harmful, such as the smell of burning plastic, ammonia, or feces – a distortion called parosmia.
Eric Reynolds, a 51-year-old probation officer from Santa Maria, California, lost his sense of smell when he contracted COVID-19 in April. Now, he said, he often picks up unpleasant smells that he knows don’t exist. Diet drinks taste like dirt; soap and detergent smell like standing water or ammonia.
“I can’t wash the dishes, it makes me sick,” Reynolds said. He’s also obsessed with the ghostly smells of corn chips and a scent he calls “ the scent of old women’s perfume. ”
It’s not uncommon for patients like Reynolds to develop food aversions related to their biased perceptions, said Evan R. Reiter, medical director of the Center for Smell and Taste at Virginia Commonwealth University, which has been following recovery for about 2000. COVID-19 patients who lost their sense of smell.
One of his patients is on the mend, but “now that he comes back, he says that all or most of what he eats will give him a gasoline taste or smell,” said Reiter. The sense of smell can be part of the recovery process, because receptors in the nose have trouble waking up and send signals to the brain that are misread or misread, he explained.
After the loss of smell, “different populations or subtypes of receptors may be affected to different degrees, so the signals the brain is used to receiving when eating a steak will be distorted and may lead the brain to think that it is so. eating dog poo or something that isn’t tasty, ”concluded Reiter.