Taste changes

Cancer treatments can cause changes in how food tastes. These changes can be a decrease in taste (called hypogeusia), altered taste (called dysgeusia) or loss of taste (called ageusia).

Taste changes can contribute to loss of appetite, weight loss and malnutrition.

You experience taste through your taste buds, which are found mostly on your tongue but also on the roof, back and sides of your mouth and back of your throat. The basic sensations that your taste buds deliver are sweet, sour, salty, bitter and umami (savouriness). Any cancer treatment that affects the taste buds or damages these areas can cause taste changes.

The taste buds are very sensitive to radiation. People who receive radiation therapy for head and neck cancers may have damage to their taste buds and changes in their sense of taste. The taste changes begin early, often during the first 2 weeks of treatment. They are usually most noticeable about 2 months after treatment begins. The changes will be different for each person, but changes in the taste of salty and bitter foods are usually more noticeable than for sweet foods.

Radiation therapy to the head and neck can cause other oral side effects like a dry mouth and a sore mouth and throat, which can make taste changes seem worse. Having a dry mouth can affect your sense of taste since saliva is important for bringing food in contact with the taste buds.

Radiation therapy to the chest can also cause changes in taste, but the reason is not clear.

Chemotherapy drugs can damage the taste buds and cause taste changes. The changes vary a lot from person to person. Common changes include bitter foods tasting more bitter than usual, sweet foods tasting less sweet than usual and having a metallic taste in the mouth.

Chemotherapy drugs that commonly cause taste changes include:

• cyclophosphamide (Procytox)
• dacarbazine
• doxorubicin

• fluorouracil

• methotrexate (Metoject)
• cisplatin
• paclitaxel

• vincristine

Taste changes caused by chemotherapy can seem worse if you have dental or gum problems or mouth infections or if you don't take care of your teeth.

Surgery can cause taste changes if parts of the mouth, throat or tongue are removed.

Some immunotherapy drugs can cause taste changes.

Interleukin-2 (aldesleukin, Proleukin) affects the lining of the mouth and can cause oral side effects, including taste changes.

Interferon alfa (Intron A) can cause decreased taste, so foods seem less flavourful. It can also cause taste changes. Foods may taste salty, bitter or metallic. Sweet foods may taste so sweet that you cannot eat them. Certain foods or beverages that you enjoyed before may no longer appeal to you.

Other factors related to cancer can also cause taste changes, including:

• growth of head and neck tumours into areas related to taste
• nerve damage
• low levels of nutrients (for example, zinc, copper, niacin)

• medicines

Taste changes can vary depending on their cause and other factors. They are different for each person. Taste changes may include:

• changes in the way food tastes
• foods tasting rancid or metallic
• foods having a "chemical" taste
• foods tasting less sweet, sour, salty or bitter than before
• foods tasting more sweet, sour, salty or bitter than before
• foods having little or no taste
• a sudden dislike for certain foods, like meat
• feeling like food creates a tasteless ball of goo in your mouth

Taste changes may affect your eating behaviour. Your ability to taste is closely related to your appetite and interest in eating. When you cannot taste food, you may lose your appetite and your enjoyment of food. This may cause you to lose weight. These things can lower your mood and reduce your quality of life.

Let your healthcare team know if taste changes are a problem for you.

Taste usually returns to normal several weeks to months after cancer treatment is finished. Some people with taste changes following radiation therapy will experience a slow gradual improvement in taste that may take place over years. But some people find that their sense of taste is permanently decreased. This is more likely after surgery or radiation therapy.

Check with your healthcare team or a registered dietitian for other suggestions on how to deal with taste changes. Your healthcare team can refer you to a registered dietitian. You can try the following to help you cope with taste changes.

General tips

• Try new foods that you don't usually eat.
• Avoid foods that do not appeal to you. Use a straw for drinks that taste different.
• Add flavour to your food with herbs and spices.
• Keep your mouth clean by brushing and flossing your teeth.
• Eat foods cold to reduce strong tastes.
• Use flavourful condiments like barbecue sauce and mustard.
• Marinate meat, fish and vegetables to improve their flavour.
• Choose other sources of protein (such as eggs, fish, nuts, beans) if meat tastes strange.
• Chew gum or suck on sugar-free candies or mints to get rid of unpleasant tastes after eating.

Coping with metallic tastes

• Use plastic or bamboo cutlery or chopsticks to eat.
• Use glass or ceramic cookware.

Coping with bitter or sour tastes

• Avoid sour or tart foods.
• Add a little honey, sugar or other sweetener to foods.

Coping with sweet tastes

• Eat sour or tart foods.
• Add lemon, lime or vinegar to foods.

Learn more about eating well during and after treatment.