Science

Cancer, chemotherapy, and food

It does not taste like it used to

Imagine your favourite foods taking on the taste of a mouth full of nails. One of the lesser-known side effects of chemotherapy is how people’s taste and sense of smell changes. Irene IJpma received her PhD for research into that change.
By Tim Bakker / Translation by Sarah van Steenderen

According to Irene IJpma, taste change is an effect of chemotherapy that receives too little attention. She received her doctoral degree for her research into taste changes in people with testicular cancer.

Cancer patients undergoing chemotherapy often experience a change in their taste and sense of smell, often combined with a metallic taste in their mouths.

Ewald Lausberg, now in remission, recalls the sensation as ‘gross’ and ‘nauseating’.

The taste change is caused because taste buds are damaged by the chemo, but the effect appears to be different for everyone.

This change in taste also affects patients’ social lives. Having dinner or drinks together becomes more difficult.

Reading time: 8 minutes (1,500 words)

The change in taste and sense of smell is an effect of chemotherapy that receives too little attention, says Irene IJpma. ‘Many people suffer from it, but they don’t tell their doctors because they think it’s normal.’

‘Research into the effects of chemotherapy does mention this taste change that patients experience. It’s often accompanied by a strong metallic taste during eating. Someone described it as having a mouth full of nails. But no one knew how exactly their sense of taste changed.’

She followed a group of young men with testicular cancer who all received the same treatment, as well as a group of former patients who had all been treated successfully over the past years. ‘By studying a homogeneous group, we wanted to research whether there was a pattern to the taste change, so we’d be able to prepare and advise future patients for it.’

One of the patients in the research was Ewald Lausberg. Prior to his treatment, his doctors asked him if he was willing to participate. ‘I was. I didn’t really know what to expect beforehand anyway. But when I experienced that taste for myself, I wanted to know what types of food I’d be able to handle.’

Sweet, sour, salty, bitter

The taste you experience is based both on the taste in your mouth and the smell of what you eat or drink. The tongue contains thousand taste buds with receptors for the flavours sweet, sour, salty, bitter, and umami, which is the Japanese word for ‘savoury’.

Each bud contains receptors for all flavours. The claim that you taste certain flavours best on certain parts of your tongue is not true. The flavours are transmitted to your brain through your brain stem. The smell of food and drinks also plays an important role in how you experience taste.

That experience changes during chemotherapy. That is because chemotherapy mainly influences rapidly dividing cells in the body, IJpma explains. That means not just cancer cells, but also your taste and smell receptors.

Chemotherapy was not the only therapy to cause a metallic taste in people’s mouths. ‘Patients who were being treated with targeted therapy or therapy combined with radiotherapy indicated experiencing that metallic taste in their mouths. But we don’t yet know what causes that exactly.’

Milkshakes and noodle soup

‘It’s a taste I never experienced before’, Lausberg remembers. ‘A truly metallic flavour. It wasn’t there all day, but always when I ate. It completely took over my taste buds. Nothing tasted like it should have. I’d have a craving, and my brain knew what it was supposed to taste like. But whenever I ate something, it didn’t just taste different, but also really unpleasant. Not just “not that great”, but seriously gross. And as my treatment progressed, so did that gross taste.’

At first, he experimented to see what foods he could or could not stomach, he says. ‘But after a while, I just tried fewer things. There were a few foods I could handle. The rest I simply didn’t eat. I’d rather eat the same things over and over and enjoy them than get nauseated by that gross flavour again. My food toleration decreased immensely. The last few weeks of my treatment, I subsisted on nothing but milkshakes, noodle soup, and white bread with chocolate sprinkles.’

Milkshakes and noodle soup. Could they be the solution during chemo? IJpma say it is impossible to day. ‘Discovering a pattern in the patients’ taste changes turned out to be very difficult. One suffered more from it than the other, and the degree differed per person. Sometimes one person’s taste experience changed over time. But most patients experienced a diminished sense of taste after their treatment, and they had become more sensitive to bitter tastes.’

Experiments

IJpma says there is simply no blanket advice to give, no matter how much she and Lausberg wanted there to be. Patients will simply have to keep experimenting on themselves with the aid of a tailored diet. ‘It’s important for patients to keep their weight up during chemotherapy. But they often have a higher percentage of fat after treatment, especially around the stomach area, while their muscle mass and bone density have decreased. Testosterone levels are a factor in that.’

It is important that this is taken into account in patients’ diets. The fact that there are significant differences between patients and that the study did not result in a clear, singular cause for the change in taste makes this difficult. ‘That means each and every patient needs a tailored diet to limit the health risks.’

Joy of eating

And yet physical health is not the only factor. ‘Enjoying your food is important, too’, IJpma emphasises. ‘Eating and drinking are social activities.’

Going out to dinner is not half as fun if you hate all foods, Lausberg found. ‘I just didn’t feel like going out anymore because the food was disappointing every time.’ Luckily, he overcame his cancer, and the metallic taste eventually subsided. Going out to dinner became fun again. ‘When my results came back positive and my old sense of taste returned, I truly had cause to celebrate.’

Although he does not enjoy sweet things as much he used to, Lausberg is mainly happy to be healthy and able to appreciate food again. He realises there are plenty of other people who will have to go through what he is going through. ‘This study is good for science, but it still needs a lot of work.’

IJpma agrees that her PhD research was just a first step. ‘We definitely need to follow up on this.’

Nederlands

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