Long-covid Sequelae: Nearly Half COVID-19 Diagnosed Still Suffer from Anosmia

Nearly half of people infected with COVID-19 still suffer from the abnormal smell and taste a year later. This affects daily diet, relationship building, emotional problems, and memory. Experts suggest slowly regaining lost flavors by stimulating daily scents and pairing special recipes.

Taipei, TAIWAN (Merxwire) – It has been more than two years since the COVID-19 virus spread, and many people are still suffering from long-covid, and an abnormal sense of smell is one of the symptoms. More than half of patients develop anosmia after diagnosis. About 20 to 35 percent of people experience symptoms of hyposmia. After long-term follow-up, it was found that 46 percent of the diagnosed still had an abnormal sense of smell one year after infection, and 7% of the patients completely lost their smell.

The latest study found that between 12 and 18 months after diagnosis, 34 percent to 46 percent of patients still had an abnormal sense of smell. In addition to complete loss of smell or hyposmia, some people experience parosmia, which is a change in the perception of smells, such as feeling the smell of fresh apples turn sour. According to research from the University of Washington, most people with parosmia feel the smell is worse than before. The study found that anosmia is more troublesome for young people than for the elderly.

Possible Causes of Olfactory Disorders

• Virus attacks sustentacular cells in the nasal cavity, resulting in a reduction of odor-detecting receptors: After diagnosis, the virus will attack olfactory neurons or sustentacular cells in the nasal cavity, disrupting the arrangement of chromosomes in the nucleus, allowing odor-detecting chemoreceptors on neurons decrease, affecting olfactory sensitivity.
• After being infected, a gene mutation occurs, which changes the sense of smell: The study found that the possible reason for the long-term abnormal sense of smell in the diagnosed person is that the two pairs of genes UGT2A1 and UGT2A2 have mutations after infection, which affects the ability of the epithelium to eliminate odor molecules, resulting in long-term changes in smell and taste.
• The olfactory area of the brain damaged and the response to detect and receive odors atrophy: A British study found that after the loss of olfactory function, a second brain tomography scan found significant changes in the brain, including reduced gray matter density and tissue density, olfactory Cortical damage, and generalized brain atrophy in a minority. These phenomena lead to a simultaneous decline in the brain’s ability to detect odors and respond to olfactory stimuli.

In addition to the COVID-19 virus, other possible causes of loss of smell include brain trauma, dementia, psychosomatic disorders, or other viral infections.

Olfactory Disorders can also Make a Difference in Life

The following is a summary of the impact of long-term loss of smell on your health and life after contracting COVID-19:

• People who couldn’t smell may eat stale food and causing diseases such as gastrointestinal infections. In addition, the taste of food is related to the aroma of food entering the nose, because our taste can only taste sour, sweet, bitter, and salty. As a result, there is no smell, and the taste and pleasure of eating are reduced.
• The smell of food could make us feel delicious and increase our appetite. Therefore, the lack of smell reduces appetite and makes it less likely to cause hunger, so our weight will reduce when symptoms of the olfactory disorder occur in the beginning. But when we start to eat according to our preferences and may choose food that is more satisfying to our senses, such as fried crispy fried food. We will accidentally ingest higher calorie intake and cause weight problems.
• Studies have found that the inability to smell can also affect normal interpersonal and partner relationships. When we can’t smell ourselves, we will become socially insecure and our emotions become sensitive. At the same time, happiness decreases when interacting with family members, partners, or friends. The number of friends, the quality of relationships, and even normal intimacy can be affected.
• In view of the various effects mentioned above and the fact that research has found that one-third of patients treated for an abnormal sense of smell after diagnosis feel that their quality of life and well-being has decreased compared to before the symptoms appeared, and they began to experience depression. In addition, loss of smell also affects the brain’s memory mechanism, so there will be symptoms of inattention or memory loss.

Can I Get My Olfactory Sensation Back?

Since smell and taste are susceptible perceptions, there is currently no complete drug treatment. Other tested methods such as steroid therapy and plasma therapy did not appear to be very effective. For the abnormal sense of smell caused by the virus, it is currently considered that the most effective treatment method is olfactory training.

During the treatment, one odor is inhaled in the morning and one in the evening for about 20 minutes each time to train the sense of smell and stimulate the brain’s response to the smell. Although it is difficult to completely restore olfactory sensation, it does have the effect of improving the sense of smell over time. And you can also start with self-training at home, and then seek medical treatment depending on the situation. It’s just that this method has a limited effect on people who have completely lost their olfactory sensation.

Because the olfactory sensation is closely related to the deliciousness of the food, some scholars have tried to start from the perspective of food and beverage, hoping to combine the smell and taste to stimulate the brain of the patient and improve their sensitivity to smell. Professor Barry Smith of the Centre for the study of the Senses, University of London, has teamed up with Life Kitchen, a non-profit cooking school in the UK, to launch free special recipes and cooking courses. They hope to improve the sense of smell and taste from a scientific point of view and help people find the true taste of food.

Start with the “umami” of the food to enhance the sense of taste buds, and add ingredients with special flavors such as mint, cinnamon, and wasabi to the food. Stimulates the “trigeminal nerve” during chewing and transmits information to the facial nerve to increase the fun of eating. Choose ingredients with heavier “smells” or faster volatilization rates, such as cheese and citrus fruits, to enhance the sense of smell.

Combining ingredients with different “tastes” and “taste layering”, you can feel the softness, crispness, and elasticity of the food as well as the freshness, sweetness, bitterness, and saltiness of the food while chewing. Multiple layers of richness in food can provide more freshness and stimulation to smell and taste, and also contribute to the recovery of olfactory sensation.

Although your sense of smell may not be fully restored, there is still a chance to retrieve some of the true flavors and reduce the after-effects of COVID-19 through various smell training. If you are also suffering from olfactory disorders in long-covid, it is better to start with daily odor stimulation, and then seek medical and professional assistance in time to help you regain your olfactory sensation.