Humans eat to satisfy hunger, but we also eat for pleasure.
When people no longer derive pleasure from eating, their appetite may be severely altered. That's because when food doesn't taste good, eating becomes a health maintenance chore, like tooth flossing or walking on the treadmill.
"Patients who have impaired taste often report forgetting to eat, which is hard for someone with normal taste function to imagine," said Laura McLaughlin, PhD, RN, OCN, assistant professor at Saint Louis University School of Nursing in Missouri.
The 2005 Institute of Medicine (IOM) report on cancer survivorship called for increased awareness of the psychosocial and functional consequences of cancer and cancer therapies and the development of strategies to achieve improved quality of life.
"Increasing awareness of taste dysfunction, its consequences and potential strategies to mitigate the problem are important goals for oncology nurses," McLaughlin noted.
Causes & Treatment
Dysgeusia (dysfunction of the sense of taste) in patients with cancer may be caused by a number of treatment- or tumor-related factors. The presence of cancerous tumors is associated with higher levels of inflammatory cytokines, which are known to disrupt taste sensation transmission.
In addition, taste cells need an adequate nerve supply to function properly. Tumors in the head and neck have the potential to compress nerves; surgery to the head and neck may sever nerves; and radiation may damage the nerves of taste transmission.
"Most taste cells are found on the tongue, so it is easy to understand why patients with tongue cancer are at risk for taste dysfunction," explained McLaughlin. "Many chemotherapeutic agents cause de-epithelialization of the oral cavity and tongue. De-epithelialization results in fewer cells capable of receiving and transmitting taste sensations."
She also noted that radiation therapy to the head and neck is associated with dry mouth and that the saliva of patients with dry mouth is more acidic and more highly concentrated in sodium than normal.
"Basic tastes have additive and subtractive effects upon each other, and so having too much salty or sour taste changes the intensity of other salty or sour foods and also affects the taste of sweet and bitter foods," McLaughlin said.
Treatment for taste dysfunction is focused on prevention. Modern radiation therapy techniques attempt to spare the salivary glands as much as possible. Additionally, drugs such as ethyol (Amifostine) may be given during treatment in an attempt to prevent post radiation therapy dry mouth.
Karen Ulmer, BSN, RN, CORLN, added that artificial saliva agents or oral moisturizers may relieve dry mouth and provide a degree of improvement in taste dysfunction.
"We often recommend using non-metallic utensils and avoiding metallic or bitter-tasting foods," the otolaryngology nurse specialist at The Milton J. Dance, Jr. Head & Neck Center at
Greater Baltimore Medical Center remarked. "Adding spices and seasonings to food can also be of a benefit to those experiencing taste dysfunction. Sometimes eating food that is cold or at room temperature can minimize unpleasant taste and odor."
Flavors are recognizable by combined sensory data which includes taste, smell, texture, look and heat. When taste is impaired, cold or room temperature foods is less flavorful because aroma is enhanced by heat.
An Integrative Approach to Nutrition
Today, nearly 20% of all cancer deaths are attributable to malnutrition, according to the National Cancer Institute.
Patients undergoing chemotherapy, radiation and surgery commonly experience nutrition impact symptoms that alter their ability to consume food and absorb nutrients from the digestive tract. In addition, cancer itself can truly alter the actual metabolism of carbohydrates, fats and proteins.
"Knowing this, it's not too surprising that people with cancer often struggle to eat and maintain a healthy weight," said Kristen Trukova, MS, RD, CSO, CNSC, LDN, nutrition/clinical oncology dietitian at Cancer Treatment Centers of America (CTCA) at Midwestern Regional Medical Center in Zion, Ill.
CTCA at Midwestern uses an integrative approach to care for patients undergoing cancer treatment. Registered dietitians work with patients from the first visit forward to identify and work toward specific goals to help them stay strong during treatment.
Traditional tools for fighting cancer, such as surgery, radiation, chemotherapy and immunotherapy, are used in conjunction with supportive therapies, including nutritional support, naturopathic medicine, mind/body medicine, oncology rehabilitation, pain management, chiropractic care and spiritual support.
Each member of the patient's care team works together and shares patient information to provide personalized and coordinated care.
At CTCA, nurses are typically the first in the care team to identify taste alteration as a problem through their assessment. They then inform the dietitians on each team of any nutrition impact symptoms so the dietitians can further assess and create a plan of care.
Nurses assess compliance to any nutrition supplements or medications that have been prescribed for taste alteration through a medication reconciliation process and are critical in reinforcing the recommendations of the dietitian to patients.
"If the patient is experiencing any nutrition-related issues, nurses immediately make note of the issue and turn to the clinical oncology dietitians for assistance," said Trukova.
A few usual interventions might be:
- Encourage patients to try a different protein source, such as poultry, fish, eggs, dairy, soy products, protein powder or beans if meat is unappealing.
- Suggest they choose room temperature foods and/or using marinades/spices to mask strange tastes.
- In some situations, taking a zinc supplement can benefit patients with taste alterations.
"We are aware that a plant-based diet can reduce both cancer risk and cancer recurrence. When patients finish treatment, we work with them to include more plant foods in their lifestyle," Trukova commented.
The Importance of Educating Patients
Ulmer said it's important for patients to be educated as to the expected side effects of treatment and duration.
"I tell patients prior to their beginning XRT/chemo that dysgeusia is an anticipated side effect. We discuss onset and duration as well as symptom management strategies, which include use of non-metallic utensils, meticulous oral hygiene, and trialing use of different seasonings and temperature on their food. Each patient will react differently, so there is no one tried-and-true treatment," she explained.
Nurses in The Milton J. Dance, Jr. Head & Neck Center at GBMC even provide a cookbook compiled by patients and staff that includes symptom management strategies for the most commonly anticipated side effects of head and neck cancer treatment.
McLaughlin noted that taste dysfunction is an under-recognized and under-reported problem. Poor recognition of the problem of taste dysfunction may be related to limited nurse/patient contact in the follow-up setting, she said. In many cancer centers, registered nurses staff the treatment rooms and the hospital floors, but nursing care is limited in the follow-up clinics.
"Oncology nurses are experts at monitoring patients during treatment for side effects, such pain, nausea, vomiting, diarrhea and weight loss. However, we often think of taste changes as time-limited side effects like nausea or mouth sores," observed McLaughlin. "Taste dysfunction can be a long-term problem for many patients with cancer.
"Patients and families who are educated about the problem will be more likely to report symptoms at follow-up and seek nursing care in the post-treatment phase of survivorship."
Beth Puliti is a freelance writer.