Taste and Smell

It has always been assumed that the number of taste buds declines with age but that does not appear to be the case. There is no evidence that taste cells are no longer regenerated or that the structure of taste buds changes in healthy older adults. However, both disease and medication use may affect this process. For example, drugs that interfere with cell division or growth, such as cancer chemotherapy agents, can disrupt both taste and smell.

Some, if not all, of the observed taste losses with age may be caused by a cumulative history of disease or by the chronic use of medications. Nerve damage during the extraction of wisdom teeth has been found to reduce taste pore density (and presumably taste bud density) in the front of the tongue. Surgery to repair the nerve increases taste pore density and partially restores taste function.

Ear infections can also cause nerve damage. A history of middle ear infections has been associated with taste abnormalities. Damage from bacterial or viral infection may result in an enhanced perception of bitter taste or in taste phantoms. Taste phantoms are a taste sensation in the absence of a stimulus. Scientists believe that taste nerves mutually inhibit each other. A lessening of nerve input from one area of the tongue may cause another area to take over and thus maintain the level of taste sensation. This may explain why older people often do not perceive a loss in taste, even when damage to taste nerves is readily apparent to a medical professional.