For many people affected by cancer, eating and drinking can become unexpectedly challenging. Once enjoyable foods may taste bland, metallic, overly sweet, or even unpleasant. These changes can occur before treatment starts, during therapy, or after treatment ends. Understanding the reasons behind these changes and how to manage them is essential for maintaining nutrition, strength, and quality of life throughout cancer care.
Understanding flavour
Flavour is more than just taste; it results from the combined effects of taste, smell, and touch. Taste is detected by the taste buds on the tongue, which recognise five basic flavours: sweet, salty, sour, bitter, and umami (savoury).
Smell, sensed by olfactory receptors in the nose, works in conjunction with taste to provide the full perception of flavour. Touch, encompassing the texture, temperature, and mouthfeel of food, also influences how enjoyable eating can be. When you eat, signals from your mouth and nose travel to the brain, which combines them to create the complete flavour experience. If any part of this system is affected, food may taste different, feel unusual, or seem less appealing.
How cancer can affect taste and smell
In some cases, cancer itself can alter taste and smell even before treatment begins. Tumours may disrupt nerve pathways or interfere with normal metabolic processes, leading to subtle changes in appetite or flavour perception. Emotional factors such as stress, anxiety, and fatigue can also affect how food tastes.
However, most changes in taste and smell are caused by cancer treatments. Chemotherapy, which targets fast-growing cancer cells, can also impact healthy cells, including taste buds.
Common effects include a metallic or bitter taste, a reduced ability to taste food, heightened sensitivity to certain flavours, and changes in how hot or cold foods feel. These effects may vary daily and are often more noticeable in the first week after treatment.
Radiation therapy to the head or neck can damage taste buds and salivary glands. Saliva is essential for dissolving food so taste buds can detect flavour. A reduced saliva production can lead to a dry mouth, altered food smells, and changes in sensation in the mouth and throat. Some patients may experience long-lasting taste changes due to radiation.
Surgery involving the mouth, nose, or throat can also impact the tongue, nasal passages, or salivary glands, resulting in altered taste, smell, and texture perception. Nerve damage from surgery can affect flavour perception for weeks or even months after recovery.
Dry mouth and mouth sores
Many treatments reduce saliva production, leading to dry mouth (xerostomia). Without enough saliva, food may taste bland or unpleasant, chewing and swallowing can become difficult, and sensitivity to spicy, acidic, or salty foods may increase. Some patients also develop painful sores in the mouth, known as mucositis, which further reduces appetite.
Maintaining oral hygiene is vital during this time. Gentle brushing with a soft toothbrush, rinsing with warm salt water or a dentist-recommended mouthwash, staying hydrated, and visiting the dentist regularly can help preserve oral health and improve taste perception.
Flavour perception is influenced not only by the senses but also by context and emotions. Eating in a hospital, associating certain foods with treatment, or feeling anxious can reduce enjoyment of meals. Even familiar foods may taste unpleasant during or immediately after chemotherapy due to nausea or stress.
How long changes last
The duration of taste and smell changes varies depending on treatment type, cancer location, and individual factors. Taste often changes during chemotherapy cycles, but many patients regain normal taste within two months after the final cycle. Changes from radiation to the head or neck may persist longer, especially if saliva production is reduced. Recovery from surgery depends on the procedure’s extent and nerve involvement, sometimes taking weeks or months. Patients should discuss specific expectations with their healthcare provider.
Coping strategies
Understanding that taste and smell changes are common and usually temporary can provide reassurance. Keeping a food diary to track what tastes good or bad, experimenting with different foods, textures, and flavours, eating small, frequent meals, including high-protein foods such as eggs, dairy, beans, lentils, nuts, or fish, maintaining oral hygiene, and using straws for liquids to bypass sensitive taste buds can make a significant difference.
Consulting a dietitian may also help provide individualised advice and meal plans to ensure adequate nutrition.