Sensory changes like taste and smell changes are extremely common, affecting up to 70% of people with cancer during treatment². They can occur in any form of cancer but are particularly frequent in patients with head and neck cancer³. In addition to taste changes, people with cancer may experience changes in their sense of smell and “mouthfeel” (how food or drink feel in the mouth)⁴. Taste and smell alterations generally appear shortly after patients begin treatment and may last for 6–12 months after treatment ends, sometime longer^2,5.

Having a metallic taste in the mouth is very common among people with cancer. Studies have found that as many as 78% of patients being treated with chemotherapy, radiotherapy, or targeted therapy have a metallic taste or find that food tastes metallic⁶. People with this particular side effect are also likely to report having a bitter taste in their mouth or an increased sensitivity to sour or bitter foods⁶. As well as a metallic taste, treatments for cancer may cause a “rancid” or “chemical” taste in the mouth. Fortunately, these side effects typically disappear after treatment ends².

You perceive flavor via around 5000 taste buds on your tongue and inside your mouth. The taste buds contain special cells, called receptors, which detect the basic tastes of sweet, sour, salty, bitter, and umami^2,3.Sometimes, taste changes are caused by the cancer itself interfering with the body’s normal processes^2,3. More often, however, taste changes are an unintended side effect of cancer treatment. Both radiotherapy and chemotherapy damage the tastebuds, affecting how food and drink taste; they can also affect the sensory nerves, changing how things feel in the mouth^2,3. Surgery for cancer may also affect taste and smell if it involves damaging parts of the mouth, tongue, or nose.

Treatments for cancer – particularly chemotherapy and radiotherapy – can cause a dry mouth by reducing the amount of saliva you make. Because saliva helps the tastebuds to perceive flavor, having a dry mouth can affect your sense of taste. It can also cause other problems, such as mouth infections, a sore throat, and even tooth decay2,3.

Unintentional weight loss can cause you to feel tired and weak, makes your treatment less effective, increases the chance of side effects, and reduces your overall quality of life8.

Ensuring good nutrition and avoiding weight loss is really important for patients with cancer. This will give your body the best chance of staying strong and responding well to treatment. Aim to eat high-protein and energy dense foods throughout the day to maintain your weight and keep your muscles strong. For example high protein foods include chicken, fish, tofu, cheese, eggs, nuts, beans, lentils and chickpeas are all rich in protein.

If medical nutrition is appropriate as part of any treatment you may be receiving, it is a decision that must always be made in consultation with a healthcare professional. It’s particularly important to always discuss if your appetite is reduced and/or if you are losing weight, as whatever age you may be, unintentional weight loss is never a normal part of life.