Losing the ability to fully taste and enjoy food after a viral illness like the flu is a common temporary side effect of upper respiratory infections. This loss is medically termed ageusia for complete loss of taste, or dysgeusia for distorted taste. This sensory disruption is typically a passing condition. Many people who experience a reduction in taste while recovering from the flu will see a gradual return to normal sensation as the body heals.
The Connection Between Flu, Smell, and Taste
The diminished sense of taste following the flu is overwhelmingly a problem with your sense of smell, or olfaction. True taste, perceived by the tongue, is limited to five basic sensations: sweet, sour, salty, bitter, and savory (umami). The complex, recognizable flavor of food, such as a cherry or a lemon, is actually a combination of these basic tastes plus the aroma detected by the nose.
When you chew food, volatile odorant molecules travel up the back of your throat to the olfactory epithelium, the patch of tissue at the roof of the nasal cavity. The influenza virus triggers an immune response that causes inflammation and swelling in the nasal passages and sinuses. This inflammation leads to congestion and excess mucus production, which physically obstructs the path of odor molecules from reaching the olfactory receptors.
In some cases, the virus may also cause direct damage to the supporting cells that maintain the health of the olfactory sensory neurons. When these cells are compromised, the neurons responsible for transmitting smell signals to the brain cannot function properly, leading to post-infectious anosmia, or the loss of smell.
Methods to Help Restore Sensory Function
To encourage the recovery of your sense of smell and taste, a technique called smell training is widely recommended. This process is essentially physical therapy for the olfactory nerve, aiming to stimulate nerve regeneration and improve the brain’s ability to recognize scents. The standard protocol involves repeated, intentional exposure to a set of strong, distinct odors.
The training requires gathering four essential oils representing different scent categories:
- Floral (like rose)
- Fruity (like lemon)
- Spicy (like clove)
- Resinous (like eucalyptus)
Twice a day, hold each scent up to your nose for 10 to 20 seconds, sniffing gently. While inhaling, focus intently on the smell and try to recall the scent from memory. It is recommended to perform this exercise daily for at least 12 weeks, and often for several months, to see noticeable improvement. Nasal hygiene can also support this process by reducing inflammation that blocks the nasal passages. Using a saline nasal rinse or spray helps clear mucus and reduce swelling, allowing odor molecules better access to the olfactory region.
Coping Strategies for Enjoying Food While Recovering
While actively working to restore your senses, you can use other sensory inputs to make mealtimes more pleasurable and ensure good nutrition. Since true taste sensations remain, focus on foods that emphasize the five basic tastes. Incorporating sour lemon juice, salty broths, or spicy chili flakes into your meals can make food more engaging even without the full flavor profile.
Concentrate on the physical properties of food, such as texture and temperature. Introducing contrasts can enhance the eating experience, like pairing something crunchy, such as nuts or crisp vegetables, with a smooth, soft food. Varying the temperature within a meal, perhaps having a cold salad alongside a warm main dish, also provides a greater sensory experience. Focusing on the visual appeal of a dish, using colorful foods and attractive plating, can also help stimulate appetite and enjoyment.
Food Safety Considerations
A diminished sense of smell can make it difficult to detect spoiled food or gas leaks. It is important to be mindful of food safety during this time. Be sure to check expiration dates carefully and rely on visual cues or the judgment of others to confirm food freshness.
Recovery Timeline and When to Seek Medical Advice
The loss of taste and smell associated with the flu is temporary, and the senses begin to return as nasal inflammation subsides. While recovery varies, many individuals notice gradual improvement within a few weeks of the illness resolving. The full return to normal can take weeks or even a few months, and patience is required during this period of healing.
If your loss of taste and smell persists without any signs of improvement after approximately four weeks, or if the loss occurred suddenly without a clear viral infection, it is advisable to consult a healthcare provider. An ear, nose, and throat (ENT) specialist may perform an examination to rule out other causes, such as a nasal obstruction or other underlying conditions. Seeking professional guidance is important if the change in sensation is accompanied by other concerning symptoms, like sudden changes in vision or persistent neurological issues.