Sensory Changes in Cancer Patients
Imagine that you have little to no sense of taste. Eating food is no longer pleasurable and it has now become a chore. This is likely something you would not wish upon yourself or loved one however this is a serious issue that many cancer patients experience as a part of daily life.
Humans have taste buds on the tongue and in the mouth which contain taste receptors. This allows us to sense the basic tastes: sweet, sour, salty, bitter and umami. Smell also plays a large factor in the flavor of foods. Volatiles are picked up by the olfactory receptors and in combination with the taste in the mouth, flavor is detected. Without these senses food would lack taste or would have an alteration in the taste perceived1.
Cancer can interfere greatly with the ability to taste and smell foods properly. Dysgeusia, or the change in the sense of taste2, is a common side effect of cancer as well as cancer treatments such as chemotherapy and radiation therapy. According to the Oncology Nursing Forum 38-77% of patient reported changes in the sense of taste after receiving chemo therapy3. Chemotherapy as well as radiation may cause damage to sensory receptors causing dysgeusia or even ageusia which is the complete loss of taste3. These therapies most specifically in patients with head and neck cancer can also cause olfactory dysfunction leading to altered or complete loss of smell. Metabolic changes can also occur from the presence of the cancer alone. In addition, fungal infections such as thrush, ulcers and dry mouth or xerostoma can also lead to complaints related to dysgeusia4. Some cancer-related vitamin deficiencies such as zinc, vitamin A and niacin can be related to an altered taste ! as well3.
Some of the complaints in the change of taste include metallic tastes (especially after eating meat), too bitter or salty tastes and aversions to certain foods secondary to nausea and vomiting associated with those foods. The unfortunate result of dysgeusia and ageusia in the cancer patient leads to a significant downfall in the nutritional status. Anorexia and severe weight loss along with muscle wasting typically occurs from decreased appetite all related to the loss of the desire to eat.
Although there is no treatment for dysgeusia or ageusia there are some recommendations to be made in order to alleviate some of the discomfort and lack of enjoyment while eating. It is suggested to eat cold foods when you have a metallic taste in your mouth; cold meats may be easier to tolerate. If food is too salty try to under-season and consume more bland foods. Eating smaller, more frequent meals may help with bitter taste in the mouth. If a total loss of taste is the problem, eating room temperature foods and highly seasoned foods is most recommended3.
The sense of taste and smell are two senses that may be overlooked by the average person and even taken for granted. The loss or distortion in these senses can have detrimental effects on someone such as loss of appetite, nausea and vomiting as well as severe weight loss resulting in poor nutrition status. Dysgeusia and ageusia are two side effects that need to be considered by the cancer patient, especially those undergoing chemotherapy and radiation. The side effects can sometimes be permanent; some may never fully be able to taste or smell the same again. Others have to suffer for a while but three to four weeks after chemotherapy and three weeks to two months after radiation the sense of taste and smell may begin to return for the cancer patient2.
1 McWilliams, M. 2008. Foods: experimental perspectives. 6th ed. Ohio: Pearson Prentice Hall p. 45-52.
2 Taste changes [Internet] American Society of Clinical Oncology; c2005-2009 [Accessed 2009 Jan 5]. Available from: http://cancer.net.
3 Rehwaldt M, Wickman R, Purl S, Tariman J, Blendowski C and others. 2009. Self-care strategies to cope with taste changes after chemotherapy. Oncology Nursing Forum. 36(2): E47-E56.
4 Schiffman SS. 2007. Critical illness and changes in sensory perception. Proceedings of the Nutrition Society. 66: 331-345.