Taste is a stimulus for appetite. The most common taste disorder is the distortion of the sense of taste or dysgeusia. Taste acuity declines with age but people more often report dysgeusia (distortion of taste) when they experience an abrupt alteration resulting in an overly strong/weak taste. Among the seriously ill, dysgeusia can adversely influence nutrition and quality of life as well as lead to food aversions, distorted smells, and loss of eating pleasure.
In cancer, dysguesia is most associated with chemotherapy and radiation; yet there is considerable intra-individual variability regarding the intensity of impact. Patients with head and neck cancer and those exposed to tyrosine kinase inhibitors or taxane based regimens are most at risk. Common non-malignancy causes of dysgeusia in the seriously ill include, infections, zinc deficiency, hypothyroidism, Cushing ’s syndrome, liver disease, sequelae from ENT operations, and medications such as psychotropics, opioids, and antihypertensives.
Patients often fail to volunteer symptoms of dysguesia. Hence, patients with cancer or other described risk factors should be routinely asked about distorted smell and taste.
Chemotherapy induced dysgeusia most often resolves within months. However, in that time, it can have a devastating effect. Because eating habits are shaped by life experiences and life experiences are shaped by eating habits, dysgeusia can alter customs within the family unit and lead to a reduction in socialization around meals.
Many with taste alterations try home remedies such as lemon juice, candy before meals, sweet drinks, plastic utensils, drinking from a straw, brushing teeth and tongue before meals, and using salt, soda or antibacterial mouthwashes. There is weak evidence for flavor enhancers (e.g. salt, sugar, monosodium glutamate, monopotassium glutamate) during chemotherapy.
There are a multitude of ineffective drugs: corticosteroids, vitamin A, gabapentin, gingko biloba, glutamine, and amifostine have all been shown to be non-beneficial, other medications may help, however the data are not fully convincing. A randomized trial demonstrated taste improvement with alpha lipoic acid (available over the counter); however, other studies did not reproduce this finding. Dronabinol at low doses such as 2.5 mg twice daily may improve dysguesia in advanced cancer without improving appetite. Multiple randomized trials of zinc supplementation at doses between 30 to 50 mg three times a day demonstrated a modest improvement in taste acuity and taste quality among individuals undergoing chemotherapy and/or radiation. This benefit was not observed in a non-cancer population.
Patients with taste distortion must try a variety of foods to pick the one that works for them, this time could be used to try various other cuisines that have multiple flavor’s, experimentation is the best option.