Less Taste Sensitive Tongue in Cancer Survivors

Head and neck cancer survivors report that their sense of taste is dulled, changed or lost during radiation treatment, causing them to lose interest in eating and diminishing their quality of life.

A recent study at the University of Illinois Urbana-Champaign about taste and smell dysfunction in 40 cancer survivors discovered that the tip of tongue is less sensitive to bitter, salty or sweet tastes than the control group.

‘Cancer survivors' tongues are less sensitive to tastes than those of healthy peers.’

Diminished taste sensitivity in taste buds is due to damaged chorda tympani facial nerve branches that carry signals from the tip of the tongue to the brain during radiation therapy.

"While most studies suggest that patients' ability to taste recovers within a few months of treatment, patients report that they continue to experience taste dysfunction for years after treatment ends", said M. Yanina Pepino, a professor of food science and human nutrition at the U. of I.

The research team assessed participants' smell and taste functions separately to explored the sensory interactions between taste and retro nasal odors - aromas from food and beverages that are perceived in the oral cavity while eating or drinking.

The ability to taste is tested by applying cotton swabs soaked in flavored solutions to the tip of their tongue. Whole-mouth taste function is done by swishing solutions around their mouths for five seconds and spit them out. Later the taste quality is identified.

Participants also tasted the samples twice - once wearing a nose clip and once without - to determine the difference in their taste perception.

The results of the study published in Chemical Senses revealed that the taste and smell of the all samples were rated similarly using the whole-mouth test with or without the nose clip.

When participants' sense of taste is assessed regionally at the tip of the tongue, the cancer survivors were more likely to respond they did not perceive a taste or to misidentify the taste quality - such as bitter, salty or sweet - of multiple samples.

Tongue signaling system allows taste intensity to remain constant in the whole mouth, even when taste signaling coming from the tip of the tongue is reduced. However, reduced signal input can also lead to phantom tastes, metallic taste and other oral symptoms.



Source: Medindia