One of the questions most frequently asked of patients and their relatives during the cancer treatment process is nutrition. The question “What should I eat, what should I not eat?” reflects both a legitimate concern and the confusion created by the conflicting information circulating on the internet. This article addresses, from a clinical perspective, why nutrition is important during cancer treatment and which general principles need to be taken into account.
Why Is Nutrition So Important in the Treatment Process?
Oncological treatments such as chemotherapy, immunotherapy, radiotherapy or surgery can create serious physiological burdens on the body. In this process, the body needs to repair tissues, keep the immune system functional and respond to treatment. Adequate and appropriate nutrition can play an important role in supporting these processes.
It is known from clinical observations that inadequate nutrition can adversely affect the treatment process, can reduce the patient’s capacity to complete treatment and can prolong the recovery process. On the other hand, the claims that nutrition “treats” cancer or that certain foods “kill” the tumour are devoid of scientific basis, and such approaches can adversely affect the treatment process.
The basic goal is as follows: to be able to meet the energy and nutrients the body needs throughout treatment, to be able to maintain a body weight that is as adequate as possible and to be able to manage the side effects of treatment to the extent possible.
Does the Nutritional Need Change According to the Type of Treatment?
Yes, it can change. Which treatment is applied, which region is targeted and the person’s initial nutritional status directly affect the priorities regarding nutrition. For this reason, a “single nutrition plan for the cancer patient” approach does not coincide with the clinical reality.
During the Chemotherapy Process
Chemotherapy can come with side effects such as nausea, vomiting, mouth sores, taste changes and loss of appetite. These effects vary significantly from person to person and according to the drug used. In some patients, taking an adequate amount of nutrients may become difficult; this situation may turn into a nutritional problem requiring clinical assessment. Sharing the complaints with the treatment team is important in terms of suitable support options being brought into play.
During the Radiotherapy Process
The side effects of radiotherapy that affect nutrition depend largely on which region is being treated. While difficulty swallowing and dry mouth may come to the fore in radiotherapy aimed at the head and neck region, complaints related to the digestive system may be seen more frequently in applications in the abdominal region. These complaints may require temporary adaptations in the nutritional pattern.
After Surgery
After oncological surgery, the functional changes on the digestive system and the recovery process directly affect the nutritional needs. According to the region operated on and the procedure applied, temporary or permanent adaptations may be required in the manner of eating and food preferences. In this process, dietitian support can undertake a determining role.
During the Immunotherapy Process
In patients receiving immunotherapy, the symptoms related to nutrition may follow a different profile compared to other treatment types. However, in some patients, an autoimmune-related effect on the digestive system may arise. Such developments may require the nutritional pattern to be reviewed and should be conveyed to the treatment team.
General Nutrition Principles: What Can Be Focused On?
Offering a definite nutrition list without taking individual treatment conditions into account is not a correct approach. However, there are some general principles widely adopted in the field of oncology.
Adequate protein intake stands out as a nutritional priority of particular importance in terms of tissue repair and immune functions during the treatment process. The protein need may increase according to the type of treatment and the patient’s condition; how this need is met is determined through a dietitian assessment.
The maintenance of body weight is also one of the important indicators that need to be monitored during the treatment process. Since unintended weight loss can affect treatment tolerance and recovery capacity, noticing and assessing it at an early stage is recommended.
Fluid intake is another matter that needs to be carefully monitored, particularly during periods accompanied by symptoms such as nausea, vomiting or diarrhoea. Such symptoms should be shared with the treatment team, and additional support should be brought into consideration where necessary.
Food safety is of special importance in patients whose immune system is suppressed. Not cooking, the consumption of raw foods or not paying attention to hygiene conditions can increase the risk of infection. The treatment team can provide guidance on this matter in line with individual requirements.
Coping With Loss of Appetite: What Can Be Said From a Practical Standpoint?
Loss of appetite is one of the most frequently encountered nutritional difficulties during the treatment process. During periods when eating becomes difficult, eating in small and frequent intervals instead of large meals can be a more practical approach. When changes are experienced in the perception of taste and smell, it is normal for food preferences to differ temporarily; trying to adapt to these changes does not force the patient unnecessarily.
In situations where the nutritional difficulty exceeds a certain threshold or weight loss accelerates, getting support from an oncology dietitian can facilitate the management of the process. Such support also covers clinical options such as the assessment of nutritional supplements or medical nutrition products; however, these decisions should be taken together with the treatment team.
What Should Nutrition Be Like After Treatment Ends?
The completion of treatment does not mean that the attention and care regarding nutrition come to an end. In the post-treatment period, some side effects may continue, the normalisation of digestive system functions may take time, and long-term health goals continue to be determining in nutrition planning.
In the long term, steps aimed at improving the general quality of nutrition can be evaluated both in terms of general health and in terms of the management of factors related to a possible risk of recurrence. What these steps will be and how they will be applied is a process that needs to be planned with expert support, by taking into account the individual health condition and treatment history.
Who Is an Oncology Dietitian, and When Should Support Be Sought?
Dietitians specialised in the field of oncology work in collaboration with clinicians in the management of the nutritional problems that arise during cancer treatment and in the creation of individual nutrition plans. Unlike standard dietitian support, they carry a special body of knowledge regarding the side effects of treatment, drug-nutrient interactions and clinical nutrition requirements.
The assessment of the nutritional status before treatment begins, the management of the nutritional difficulties that arise during treatment and the planning of the post-treatment period fall within the scope of this support. When any kind of complaint or question regarding nutrition is conveyed to the treatment team, a referral to dietitian support can be made where necessary.
Frequently Asked Questions
Does eating organically during treatment make a difference?
Organic foods are preferred by some patients. However, the clinical evidence regarding the effect of organic nutrition on cancer treatment is limited. During the treatment process, the priority is to maintain adequate nutrient intake; preferences that contribute to the realisation of this goal can be evaluated within the framework of individual conditions.
Can raw vegetables and fruit be eaten while receiving chemotherapy?
This is a question that varies according to the status of the immune system and the treatment being applied. During periods when immunity is markedly suppressed, it is known that raw and unwashed foods can increase the risk of infection. The treatment team can provide guidance on this matter according to the person’s clinical condition.
Can herbal teas and natural supplements be used?
The assumption that everything that is “natural” is harmless is not valid during the treatment process. Some herbal products and supplements can interact with the drugs used or can affect liver and kidney functions. For this reason, any kind of supplement and herbal product used or wished to be used during the treatment process should be shared with the treatment team.
Wouldn’t losing weight be healthy, does it weaken the tumour?
Unintended weight loss during the treatment process is not a development that weakens the tumour; on the contrary, it is a situation that threatens treatment tolerance and recovery capacity. The preservation of muscle mass stands out as an important goal in this process. When weight loss is experienced, reporting it to the treatment team is recommended.
Does taking probiotics support immunity?
Although the effects of probiotics on immunity are on the research agenda, the clinical guidance regarding their use during the cancer treatment process has not yet become clear. In situations of serious immune suppression, the use of probiotics may not be recommended. This is a decision area that needs to be discussed with the treatment team.
Can I return to normal nutrition once treatment is over?
Post-treatment nutrition planning is individual. For some patients, the marks left by treatment may permanently affect digestive system functions; for others, temporary adaptations are sufficient. In the post-treatment period, dietitian support can contribute to the healthy management of this transition.
This text is for general information purposes; it does not replace individual dietitian or physician advice. The nutrition plan during the treatment process should be shaped with expert support, by taking into account the type of treatment applied, the side-effect profile and the person’s general health condition. Do not hesitate to share your questions and complaints about nutrition during cancer treatment with your treatment team.
