Radiotherapy is not solely a treatment method targeting the tumour area it is also an intensive process that directly influences the body's energy requirements, the immune system, and overall metabolic balance. This is why the diet established during treatment plays an important role in maintaining the patient's quality of life and in their ability to tolerate the sessions more effectively. In patients receiving radiotherapy, side effects such as loss of appetite, changes in taste, mouth sores, nausea, digestive problems, and fatigue may occur, which calls for a diet adapted to each situation. A balanced diet rich in protein, healthy fats, vitamins, and minerals helps to limit muscle loss, to preserve energy levels, and to support the recovery process. For many patients, it is often more comfortable to favour more frequent meals in smaller portions rather than widely spaced and heavy meals. It is also generally advisable to avoid overly fatty, very spicy, or ultra-processed foods in favour of more natural and easily digestible options.
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During radiotherapy, eating is not simply about consuming food it also represents a genuine form of therapeutic support that contributes to the body's repair mechanisms. A sufficient protein intake is particularly important for promoting tissue renewal. Eggs, yoghurt, kefir, cheese, fish, poultry, red meat, and plant-based protein sources should be consumed regularly. Fruit and vegetables, thanks to their richness in antioxidants, can also help to support the immune system. However, in some patients, fibre-rich foods may heighten intestinal sensitivity, so their consumption should be adjusted with the guidance of the doctor or dietitian. The dietary approach may also vary according to the area being treated. For example, patients receiving radiotherapy to the head or neck may experience difficulty swallowing; blended, soft, and non-irritating foods are then preferred. Conversely, for abdominal radiotherapy, a lighter diet aimed at preserving intestinal comfort may be more appropriate. For this reason, it is preferable to avoid standardised diets and to adopt a nutritional approach that is personalised, balanced, and sustainable.
Why Is Diet Important During Radiotherapy?
An appropriate diet during radiotherapy is essential for reducing the physical exhaustion caused by the treatment and for enabling the body to maintain its capacity for recovery. During this period, cell renewal may be altered, leading to an increase in energy requirements. When food intake becomes insufficient, this can result in weight loss, muscle wasting, a weakened immune system, and a general decline in physical capacity. In patients suffering from a lack of appetite, a reduction in food intake can also make the treatment harder to tolerate. It is therefore essential that individuals undergoing radiotherapy do not simply eat but provide their body with the fundamental nutrients it needs. A shortage of energy and protein can slow the recovery and complicate daily activities. Appropriate nutritional support thus helps the patient to remain stronger, both physically and mentally.
The importance of diet is also explained by its role in reducing certain side effects associated with radiotherapy. In some patients, dry mouth, loss of taste, nausea, or intestinal problems make everyday eating more difficult. In this context, the choice of food becomes decisive in improving the patient's comfort. For example, meals that are high in calories but small in volume can be advantageous when appetite is poor. A protein-rich diet can help to limit muscle loss, whilst a sufficient intake of vitamins and minerals contributes to maintaining the immune system. It is also important to consume food that is safe and prepared under good hygiene conditions in order to limit the risk of infection. Patients should avoid going long periods without eating, should favour regular meals, and should adopt a diet that does not place unnecessary strain on the body. Nutritional support during radiotherapy influences not only the course of the treatment but also the recovery phase that follows.
How Should Hydration Be Managed During Radiotherapy?
During radiotherapy, hydration plays an essential role in maintaining the body's overall balance and in reducing certain side effects of the treatment. In patients experiencing fatigue, dry mouth, nausea, or digestive problems, an insufficient fluid intake can quickly lead to dehydration. This can worsen the drop in energy and have a negative impact on kidney function. Fluid requirements vary from one person to another, but for the majority of patients, drinking water regularly throughout the day remains indispensable. However, hydration is not limited solely to water. Fermented milk, soups, sugar-free liquid compotes, kefir, and certain drinks recommended by the doctor can also contribute to the daily fluid intake. In patients with oral sensitivity, it may be preferable to avoid very hot or very cold drinks. Drinking in small sips spread throughout the day often helps to maintain good hydration without overloading the stomach.
The management of fluid intake must take into account the area being treated, the side effects present, and the patient's general health. For example, in cases of diarrhoea, losses of fluid and electrolytes can be significant, which requires particular attention to fluid balance. Conversely, in some patients with heart or kidney problems, fluid quantities may need to be monitored closely. It is therefore important to adopt a personalised approach rather than applying the same standard quantity to everyone. Drinks containing a high amount of caffeine should be consumed in moderation, as they can promote dehydration in some individuals. Heavily sweetened fizzy drinks are also generally inadvisable, as they can worsen digestive discomfort. Regular hydration during radiotherapy helps to relieve dry mouth, to support digestion, and to preserve the proper overall functioning of the body. In patients with a poor appetite, nutritional strategies based on liquid or semi-liquid foods can also represent an effective way of increasing daily energy intake.