Causes of loss of taste include flu, Bell's palsy, the common cold, nasal infections and salivary gland infections, states MedlinePlus. Other possible causes include ear surgery, mouth dryness, heavy smoking, inflamed gums and certain medications, such as lithium, captopril and rifampin.
Loss of taste is a common aging condition that starts occurring at age 60, notes MedlinePlus. In most cases, a patient loses sweet and salty tastes first. This condition reduces the quality of life, leading to poor nutrition and reduced appetite, says Mayo Clinic. It may also result in using excess sugar or salt to enhance the taste, which can be a problem for diabetes or hypertension patients.