The COVID-19 pandemic led to a widespread loss of taste and smell. This sensory disruption became a prominent indicator of infection for many, and the sudden inability to detect aromas or flavors significantly affected daily life, transforming the simple act of eating into a bland or unpleasant experience.
Understanding Taste Loss with COVID-19
When people refer to “loss of taste” due to COVID-19, they are often describing a broader range of sensory changes that involve both taste and smell. Anosmia refers to the complete absence of the sense of smell, which is frequently reported with COVID-19. Ageusia describes the complete inability to taste, though less common than smell loss, as much of what we perceive as “flavor” actually comes from smell. Beyond complete loss, individuals may experience dysgeusia, which is an altered or distorted sense of taste, causing foods to taste metallic, bitter, or simply unpleasant. Parosmia is another common alteration, where normal smells, like coffee or shampoo, are perceived as distorted or foul, often described as chemical, burnt, or rotten odors.
How COVID-19 Affects Taste and Smell
The SARS-CoV-2 virus affects taste and smell primarily by targeting specific cells in the nasal cavity. The virus uses two key host proteins, ACE2 receptors and TMPRSS2 enzymes, to gain entry into cells. These proteins are expressed at high levels in sustentacular cells, which are supporting cells located in the olfactory epithelium of the nose.
Olfactory support cells are crucial for odor-sensing neurons. The virus infects these supporting cells, causing inflammation and damage, which indirectly impacts the nearby olfactory neurons responsible for detecting smells. While the initial infection does not directly target the olfactory neurons themselves or the olfactory bulb in the brain, the disruption to the supporting cells can impair the ability of olfactory neurons to send signals to the brain, leading to a loss or change in smell perception. Though less understood, there may also be some impact on taste bud cells or nerve pathways, but olfactory involvement is generally considered the primary mechanism for sensory loss.
Recovery and Coping Strategies
Recovery from COVID-19 related taste and smell loss varies among individuals, with many seeing improvement within weeks, though some experience longer durations. Smell training, also known as olfactory training, can aid in recovery. This involves regularly smelling a set of four distinct essential oils—such as rose, lemon, eucalyptus, and cinnamon—twice a day for several weeks. The goal is to stimulate the olfactory nerves and help the brain re-establish connections to specific scents.
While recovering, adjusting nutritional habits can help make food more appealing. Focusing on varied textures, incorporating different temperatures, and using strong flavors or spices can enhance the eating experience even when taste and smell are diminished. Cold or room temperature foods may also be easier to eat. For safety, it is important to be mindful of potential hazards when senses are impaired; this includes ensuring smoke detectors are working, checking food expiration dates, and exercising caution with strong or potentially dangerous smells like gas.
Persistent Taste and Smell Changes
For some individuals, taste and smell alterations can persist long after the initial COVID-19 infection, becoming part of what is known as “Long COVID.” These prolonged issues can include ongoing parosmia, where pleasant smells are distorted into unpleasant odors, and phantosmia, the perception of phantom smells. Common triggers for parosmia often include coffee, onions, garlic, and roasted meats. Living with persistent parosmia or phantosmia can have a significant psychological impact, leading to a loss of enjoyment from food, changes in eating habits, and even social isolation. If these persistent symptoms significantly affect quality of life, consulting a healthcare professional is advisable to explore potential management strategies and support options.