Taste alteration and cancer

ALSO KNOWN AS: Taste change, taste dysfunction, dysgeusia, hypogeusia, ageusia

RELATED CONDITIONS: Anorexia (loss of appetite), xerostomia (dry mouth), thrush (a fungal disease of the mouth), zinc deficiency, increased levels of calcium, COVID-19

DEFINITION: As the phrase suggests, taste alteration is a change in how people perceive tastes or flavors. People can recognize four main tastes: sweet, sour, salty, and bitter. Any one or all four taste sensations can be affected. Taste alteration is a symptom or side effect, not a disease. Infection in the mouth, cancer, and certain cancer treatments can change a person’s sense of taste. Taste alteration may emerge as one of three medically recognized abnormalities: dysgeusia (changes in how foods normally taste), hypogeusia (a decreased ability to taste foods), or ageusia (the complete loss of the ability to taste foods). In addition, many cancer patients complain of a medicine-like or metallic taste in the mouth that affects their sense of taste.

Risk factors: Risk factors include having cancer of the mouth, tongue, lips, or throat; receiving radiation treatments to the head or neck; receiving involving certain cancer-fighting drugs; and undergoing surgery to the head or neck. Although not specifically related to cancer, infection with COVID-19 may also cause a loss of taste and smell.

Etiology and the disease process: Although the exact causes of taste alteration in cancer patients are not known, doctors suspect three principal sources: the disease itself, radiation treatments, and certain cancer-fighting drugs.

Many cancerous tumors, found anywhere in the body, release substances that change the taste of foods or even take away people’s desire to eat.

Radiation treatments, especially to the head or neck, can damage taste buds, which changes the way food tastes to a patient. For instance, sour or bitter foods may taste especially strong, or sweet foods may not taste as sweet as they once did. Radiation can also damage the salivary glands, causing them to produce less saliva, which results in a dry mouth. Saliva contributes to the sense of taste by mixing with food particles and carrying them to the tongue. This process stimulates the taste receptors on the tongue, allowing people to experience and distinguish among the four tastes. Taste alteration from radiation may not show up until several weeks after treatment begins.

Chemotherapy changes the sense of taste in some patients. Researchers believe that some cancer-fighting drugs affect certain taste cells on the tongue and cause an imbalance of taste, changing the way things normally taste. These changes may result from damage to the cells in the mouth from chemotherapy or the spread of the drug to the tissues of the mouth.

Taste alteration in itself is normally not a serious problem. Nevertheless, it can lead to problems when patients change their eating habits. Each patient’s sense of taste changes differently. Some patients with taste alteration may avoid certain nutritious foods because their taste has changed; others may lose their appetite altogether. Taste alteration is one of the leading causes of malnutrition in cancer patients.

Incidence: Although taste alteration appears to be common among cancer patients receiving radiation treatment or chemotherapy, studies show varying degree of prevalence. More research may be needed because the condition usually does not last long and often takes place in the early stages of cancer. However, studies have shown anywhere from 15 to 100 percent of patients experience some degree of taste alteration during cancer treatment. When this condition arises in patients in the later stages of cancer, treatment and research focus more on other aspects of care, such as pain relief.

Symptoms: Taste alteration itself is a symptom or a side effect. It can, however, lead to complications in a cancer patient’s nutritional status, which causes such symptoms as mouth sores, anorexia, nausea and vomiting, diarrhea, constipation, lack of energy, and weight gain or loss.

Screening and diagnosis: Nutritional screening and assessments are done for nearly all cancer patients before starting radiation therapy or chemotherapy. Screenings identify patients who may be undernourished. Assessments establish the nutritional status of patients and determine which patients need nutritional therapy. Patients who are well nourished are better able to tolerate aggressive cancer treatments.

Treatment and therapy: There is no treatment for taste alteration. Results of some studies suggest that increased zinc may be of some benefit. Care management focuses on nutrition therapy to help cancer patients avoid malnutrition, tolerate treatment, maintain their energy and strength, fight infection, heal and recover, and improve their quality of life. In addition, dietitians suggest the following for patients who may have lost their desire to eat:

• Eat with plastic utensils.
• Use sweet marinades or strong sauces with foods.
• Eat chilled rather than hot foods.
• Use extra seasonings, spices, and herbs.
• Drink citrus juices, especially lemon, to stimulate saliva.
• Keep the mouth clean with frequent tooth brushing and rinsing.
• Supplement with high-calorie meal replacement shakes

Prognosis, prevention, and outcomes: Fortunately, for many cancer patients, taste alteration lasts only a short time and is hardly ever permanent. Normal taste returns within a few weeks to a few months after treatment ends. In terminal patients, however, taste alteration can cause or exacerbate existing and cachexia.

Bibliography

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Bloch, A. Nutrition Management of the Cancer Patient. Sudbury, Mass.: Jones and Bartlett, 1990.

Keane, M., and D. Chace. What to Eat If You Have Cancer: A Guide to Adding Nutritional Therapy to Your Treatment Plan. New York: McGraw-Hill, 1996.

“Managing Taste Changes During Chemotherapy.” Memorial Sloan Kettering Cancer Center, 15 June 2022, www.mskcc.org/cancer-care/patient-education/managing-taste-changes-during-chemotherapy. Accessed 19 June 2024.

Mosel, D. D., et al. "Oral Complications in the Treatment of Cancer Patients." Oral Diseases, vol. 17.6, 2011, pp. 550–59.

Murtaza, Babar, et al. "Alteration in Taste Perception in Cancer: Causes and Strategies of Treatment." Frontiers in Physiology, vol. 8, 2017, doi.org/10.3389/fphys.2017.00134. Accessed 19 June 2024.

Paccagnella, Agostino, Ildamaria Morassutti, and Giovanni Rosti. "Nutritional Intervention for Improving Treatment Tolerance in Cancer Patients." Current Opinion in Oncology, vol. 23.4, 2011, pp. 322–30.

Whittington, E. “Food for Thought: A Waste of Taste.” CURE, fall 2006.