Why do taste and smell changes happen in cancer treatment? 

Throughout treatment you may experience taste and smell changes. These changes can include food and drinks tasting like metal or bitter. This can lead to you being put off by certain foods, making it harder for you to keep up with a healthy lifestyle. 

The exact reason for taste changes is not clear, although it is thought that it is a result of the damage to the cells in the oral cavity, which are especially sensitive to chemotherapy and immunotherapy. About half of people receiving chemotherapy have taste changes, which usually stops about 3 to 4 weeks after treatment ends. 

During radiotherapy to the head and neck, your taste buds and salivary glands may be harmed, causing changes in your taste and smell. This usually starts to improve 3 weeks to 2 months after treatment ends, but may continue to improve for about a year. Although, if salivary glands are harmed, then the sense of taste may not fully return to the way it was before treatment.

When my senses are affected by cancer treatment, why can I not enjoy my food?

The senses of smell and taste combine at the back of the throat, and if one’s sense of smell is not functional, then the sense of taste will also not function. We commonly distinguish taste as one sense and smell as another, but they work together to create the perception of flavour. 

Your body uses taste and smell mechanisms to help you survive. They warn you to stay away from spoiled food and substances that could harm you. But these senses are also there to entice you to eat, so when food tastes and/or smells different, it may turn off your appetite. 

Taste changes may also be caused by the following factors: 

 

• Surgery to the nose, throat, or mouth
• Dry Mouth 
• Damage to the nerves involved in tasting
• Mouth Sores 
• Dental or gum problems 
• Nausea and vomiting 
• Dehydration 
• Allergies
• Gastric reflux

What can I do if i experience sensory changes?

Taste changes can impact your enjoyment of eating or drinking. In turn, you may not eat or drink enough for proper nutrition. Although the problem with taste changes often gets better over time after therapy ends, it can last for a year or longer. There are some things you can do to help manage taste changes and, in the process, decrease or prevent weight loss and even lower nausea symptoms. 

1. If you are sensitive to smells, use an exhaust fan, cook on an outdoor grill, or buy precooked foods. Or try cold or room-temperature foods.

2. Avoid cold foods if you are receiving chemotherapy with oxaliplatin (Eloxatin). This drug can make you sensitive to the cold.

3.Try sugar-free gum or hard candies with flavours such as mint, lemon, or orange. These flavours can help mask a bitter or metallic taste in the mouth.

4. Marinate meats in fruit juices, sweet wines, salad dressings, or other sauces.

5. Flavour foods with herbs, spices, sugar, lemon, or sauces.

6. Avoid eating 1 to 2 hours before and up to 3 hours after chemotherapy. This helps prevent food aversions caused by nausea and vomiting.

7. Keep a clean and healthy mouth. 

8. Think about taking zinc sulfate supplements, which may improve taste for some people. Talk with your doctor before taking any dietary supplements, especially during active cancer treatment.

How to get rid of metallic taste in mouth  

I experienced many taste changes during chemotherapy and the main taste change for me was tomatoes, which tasted like paracetamol! Most patients will experience something similar, and is normally called a metallic taste. This happens especially after eating meat or other high-protein foods. Using plastic utensils and glass cookware can lessen the metallic taste. 

How to reduce metallic taste
Use this solution before eating.  

- Half a teaspoon of salt and baking soda  
- 1 cup of warm water
- Mix together

Read 'Oral Care for Cancer Treatment' for more help and tips.