Changes in taste and smell are widely recognized symptoms of COVID-19, affecting many individuals. This distressing phenomenon ranges from complete loss to distortions that make familiar foods unpleasant. The impact extends beyond inconvenience, often affecting appetite, dietary intake, and overall quality of life. Understanding these changes offers valuable insight for recovery.
How COVID-19 Affects Taste and Smell
The SARS-CoV-2 virus, responsible for COVID-19, primarily impacts taste and smell by targeting specific cells within the nasal cavity and, less directly, the taste buds. The virus uses angiotensin-converting enzyme 2 (ACE2) receptors as entry points into human cells. These receptors are abundantly present on supporting cells, known as sustentacular cells, in the olfactory epithelium located in the upper nasal cavity.
When SARS-CoV-2 infects sustentacular cells, it can lead to inflammation and damage within the olfactory epithelium. This disruption affects the function of olfactory sensory neurons, which detect odors and transmit signals to the brain. While the virus typically does not directly infect olfactory neurons, damage to supporting cells can indirectly impair their ability to send signals, leading to a diminished or altered sense of smell. For taste, ACE2 receptors are also found on taste receptor cells within the taste buds, suggesting a direct pathway for the virus to impact taste perception.
Different Ways Taste and Smell Can Change
COVID-19 can manifest in various alterations to taste and smell, ranging from complete absence to distorted perceptions. Anosmia refers to the complete loss of smell, and hyposmia is a reduced sense of smell.
Taste can also be affected, with ageusia denoting a complete loss of taste and hypogeusia indicating a reduced sense. Beyond loss or reduction, some individuals experience distorted senses. Parosmia is a condition where familiar smells become distorted or unpleasant, often making pleasant odors smell foul. Phantosmia involves smelling phantom odors that are not present. Dysgeusia describes a distorted or altered sense of taste, where foods might taste metallic, bitter, or unusual.
Recovery from Taste and Smell Changes
For many individuals, changes in taste and smell due to COVID-19 are temporary, with recovery often occurring within weeks. Studies indicate that around 90% of those affected see improvement in their sense of smell within four weeks, and a similar proportion for taste within a similar timeframe. The median recovery time for smell is around 11.5 days, and for taste, about 10 days in mild cases.
For some, however, these alterations can persist for months or longer, contributing to “long COVID.” While most people regain their senses, a small percentage may experience persistent dysfunction beyond six months. The recovery process is often gradual, with improvements occurring over time.
Managing Taste and Smell Alterations
Coping with taste and smell alterations requires practical strategies to maintain nutrition and quality of life. Smell training, a recognized technique, involves regularly smelling strong scents like rose, lemon, eucalyptus, and cinnamon or clove. Performing this twice daily for several weeks or months can help retrain the olfactory nerves and improve recovery. Websites like abscent.org offer resources for smell training.
Dietary adjustments can also make eating more tolerable. Focusing on foods with varied textures and temperatures can enhance the eating experience when taste is diminished. Experimenting with strong flavors and spices, or herbs like basil and oregano, can help stimulate remaining taste and smell receptors. Staying well-hydrated can support recovery. If taste and smell issues are severe or persist, consulting a doctor is advisable.