COVID-19, caused by the SARS-CoV-2 virus, has impacted global health beyond typical respiratory symptoms. A frequently reported symptom involves changes in sensory perception, particularly taste and smell. This alteration can significantly affect daily life and overall well-being. Understanding how this virus influences these senses is important.
How COVID-19 Affects Taste Perception
The SARS-CoV-2 virus can lead to taste changes, ranging from a diminished sense (hypogeusia) to a complete loss (ageusia), or even an altered perception where things taste different (dysgeusia). Research suggests several pathways, though precise mechanisms are still under investigation. One primary factor is the virus’s impact on the olfactory system, responsible for smell and greatly contributing to flavor perception. The virus can infect supporting cells in the olfactory epithelium, leading to inflammation and impaired function, even if nerve cells are not directly infected.
Beyond smell, the virus may also directly affect taste cells on the tongue. Taste buds contain cells expressing ACE2, a protein the virus uses to enter. When the virus’s spike protein binds to ACE2 in taste cells, it can reduce ACE2 levels, potentially disrupting salt perception regulation. This interaction might explain specific changes, such as diminished or altered saltiness, rather than a complete loss of all tastes. Some theories suggest taste changes could stem from the virus affecting the central or peripheral nervous system, which transmit taste signals.
Other Causes of Taste Alterations
While COVID-19 has highlighted taste alterations, many other factors can cause changes. Common respiratory infections like the cold and flu often lead to temporary taste loss, primarily because nasal congestion affects smell, which is closely linked to taste. Allergies can also cause similar congestion and inflammation, impairing taste.
Certain medications frequently list taste changes as a side effect. These can include antibiotics, antihistamines, blood pressure medications, and some antidepressants, which might cause metallic, bitter, or sour tastes, or even dry mouth, impacting taste. Additionally, natural aging can lead to a decline in taste sensitivity as taste buds decrease in number and effectiveness, often noticed first with salty or sweet foods.
Poor oral hygiene, gum disease, and untreated cavities can contribute to taste disturbances due to bacterial buildup and inflammation. Dry mouth, whether from medications or insufficient hydration, also affects taste because saliva is necessary to dissolve food compounds for detection. Nutritional deficiencies, particularly zinc and vitamin B12, can further impair taste. Various neurological conditions and head injuries can also impact nerves responsible for taste.
Navigating Taste Changes and When to Consult a Doctor
Experiencing taste changes can be frustrating, affecting appetite and enjoyment of food. During recovery, experimenting with different food textures and temperatures can make meals more palatable. Focusing on strong, appealing flavors through herbs, spices, or tart elements can also enhance the eating experience. Maintaining good oral hygiene, including regular brushing and rinsing, is beneficial.
Seek professional medical advice if taste changes are significant, persistent, or accompanied by other concerning symptoms. A doctor can help determine the underlying cause, especially if the changes are sudden or severe. Consulting a healthcare provider is also advised if taste alterations lead to unintentional weight changes, nutritional deficiencies, or impact quality of life. An ear, nose, and throat (ENT) specialist may be recommended for evaluation if needed.