Doctor's Reference Guide To Dietetics




General information:

Diet is an important part of the total care for cancer patients. Although there are plenty of indications that a healty lifestyle reduces the risk of developing cancer, nutrition has a different role after cancer develops. Diet has no direct effect on the tumor, but must be seen as a supporting therapy. No known evidence exists to show that diet has a direct influence on the progression or remission of the tumor, but good nutritional support for cancer patients can improve the course of cancer treatment and contribute to recovery and better quality of life. The central aim is to promote the well-being of the patient.

Dietary problems experienced by cancer patients are varied and depend on many different factors, such as the type of tumor, the stage, the treatment and its side effects.


Best time to refer to the dietician:

  • Diagnosis of an oncological disease combined with at least one of the following:
  • unwanted weight loss of > 5% within 1 month or > 10% within 6 months and/or underweight (ages 18-65: BMI < 18.5 kg/m2 and > age 65: BMI < 20 kg/m2)
  • hardly any food intake or no food intake for more than 5 days, or when it is anticipated that adequate intake cannot be assured for 5 days (surgery, radiation therapy, chemotherapy)
  • if the patient has symptoms that seriously hinder food intake, food passage and/or absorption, and if these symptoms persist for longer than one week
  • unwanted weight gain during or after the treatment
  • when there are questions about (alternative) diets and/or a need for support and advice with respect to food, or a desire to use nutritional and dietetic support products (liquid meals, supplements, preparations). These subjects can also be processed in during appointments scheduled for such purposes.


Relevant information for the dietician:

  • Diagnosis: type of tumor, localization, staging, any comorbid conditions
  • Symptoms:
  • general: anorexia, food aversions, changes in taste and smell, fatigue, assistance required with eating
  • specific: mouth problems (dry mouth, mucus production, painful mouth, stomatitis), problems with chewing, swallowing and/or food passage, gastrointestinal problems (food obstruction in the gastrointestinal tract, nausea and/or vomiting, diarrhea, constipation).
  • Medication/Therapy:
  • surgery, radiation therapy, chemotherapy, hormonal therapy, immunotherapy and endoscopic therapy.
  • Nature of the treatment (intended to be curative, palliative or symptomatic)
  • Medications: to treat comorbidity, use of nutritional supplements.
  • Other: height, (changes in) weight, alternative additional treatments.


Aims of the diet:

  • maintain/improve the nutritional status, or prevent it from deteriorating unnecessarily
  • reduce the symptoms or prevent them from worsening unnecessarily
  • inform patients and/or their caregivers as thoroughly as possible about the relationship between diet and cancer (treatment)


Characteristics of the diet:

No general standard advice exists for cancer. The advice is partly based on the symptoms, the treatment, and the stage of disease. Dietary recommendations are first based on a diet composed of foods the patient is accustomed to. If necessary, other foods with similar nutritional values may be recommended or the consistency of the food may be altered. Supplementary nutrition such as liquid meals, preparations and supplements are advised for weight loss or for certain symptoms.


Enteral or parenteral nutrition is indicated when oral intake is inadequate or not possible. The choice to use enteral or parenteral nutrition should be well considered, and the benefits must outweigh the drawbacks. Depending on the symptoms and medical information with respect to the treatment and prognosis, a choice is made from the following diets:


Adequate diet

  • A diet which provides a satisfactory amount of energy, protein, vitamins and minerals in order to maintain the nutritional status and which makes daily functioning possible. This diet is aimed at the actual situation and the effects over the mid-to-long term. Prevention counseling for the long term regarding diseases such as cardiovascular disease, diabetes and cancer are not a priority. The principles of adequate diet are:
  •  Energy: basal metabolism (Harris & Benedict) + extra allowances
  • Protein: 1 g protein/kg ideal body weight
  • fats and carbohydrates: enough to cover the energy requirements (the ratio of fats to carbohydrates and their food sources are less important)
  • vitamins, minerals, trace elements: follow recommended allowances
  • Fluids: 1.5 L drinking fluids (> age 65: 1.7 L).

High-calorie and high-protein diet

  • Energy-enriched: basal metabolism (Harris & Benedict) + extra allowances (if there is severe physical stress, no more than 150% of the basal metabolism is given)
  • Protein(-enriched): 1.2-1.7 g protein/kg of actual body weight
  • High calorie and high-protein diet is relevant only if one goal is to improve nutritional status
  • vitamins, minerals, trace, elements: follow recommended allowances.

Palliative diet

  • a diet primarily aimed at maximum well-being and at resolving or coping with symptoms. A palliative diet is called for if the disease is developing rapidly, in a very progressed stage, and no cancer treatment is possible anymore. Death is expected to come more likely within a few weeks than within a few months. The principles of palliative nutrition are:
  • Intake of energy and nutrients to the extent that the patient can. Maintaining nutritional status is not a priority.
  • Intake of fluids is more important than energy-producing foods and nutrients.
  • In the palliative-terminal phase, deliberately refraining from force-feeding fluids and/or food contributes to reducing the symptoms.


Treatment time:

  • Care level is different for each patient, because cancer is not one disease, and depends on the type of tumor, disease stage, the treatment, specific symptoms and the desire for support.


Specific remarks:

  • The view that nutritional support should be withheld because food would promote growth of the tumor is incorrect. Food may well feed both the tumor cells and the ordinary cells, but not enough food harms the patient most. For patients who have a high risk of malnutrition or are already malnourished, poor nutritional status means a higher risk of complications.
  • for specific types of cancer, it may be necessary to restrict certain nutrients in the diet (protein, fat, dietary fiber)
  • When cancer is diagnosed, 50-60% of the patients experience unwanted weight loss, caused by reduced consumption or by a change in the metabolism: the anorexia-cachexia syndrome.
  • The anorexia-cachexia syndrome is a complex metabolic process, marked by muscle atrophy, weight loss, fatigue, anorexia and increased inflammatory activity, and is associated with increased morbidity. Cachexia is the primary cause of death in 20% of patients who die of cancer. Treatment options for it are limited; nutritional measures do not solve the problem. Radical removal of the tumor removes the metabolic disturbance that causes the cachexia. Supplemental nutritional therapy combined with medication and measures to promote (or retain) the muscle mass are supportive. The value of dietary preparations supplemented with omega 3 fatty acids (such as EPA, or eicosapentaenoic acid) has not been proven convincingly. Nutritional therapy cannot directly affect the catabolic effect of the disease and the treatment, but can effect the risk of malnutrition and reduce the complications associated with that.
  • For certain tumors, the resting metabolism is elevated (pancreatic and lung cancer), which would imply a higher energy requirement. The effect on the total energy requirement, however, also depends on the activity pattern: the higher energy requirement may be compensated by a reduction in physical activity.
  • During treatment and during the period of rehabilitation, in certain forms of cancer (such as breast cancer), poor body composition may be prominent, in which the fat mass has increased and the fat-free mass has decreased, with symptoms of weakness and severe fatigue. A normal body weight can mask the poor body composition, but often there is unwanted weight gain (sarcopenic obesity). 30% of all breast cancer patients gain more than 5 kg with systemic treatment. For unwantedweight gain: calorie restriction of no more than 500 kcal/day less, extra protein, combined with an exercise program.
  • A calcium-restricted diet is not indicated for hypercalcemia. The treatment consists of administering extra fluids and medication (biphosphonates).
  • For ascites (caused by tumor growth) a sodium and/or fluid-restricted diet is not advisable. A high protein diet would be desirable, but is usually not achievable in practice (full feeling, reduced appetite, anorexia) and is not advised in view of the short life expectancy.
  • The use of supplements/antioxidants for treatment of cancer is a matter of debate. Intake of a total of 200% RDA of vitamins/minerals (i.e. intake from normal food, enriched food products, drinks and/or enteral nutrition and supplements) is considered safe.
  • For more information about various tumors and their specific dietary problems, please consult the book Leidraad voor voedingsdeskundigen bij kanker.



Block KI, Koch AC et al. Impact of antioxidant supplementation on chemotherapeutic efficacy: a systematic review of the evidence from randomized controlled trials. Cancer Treat Rev. 2007; 33:407-18


Bozzetti F, Mori V. Nutritional support and tumor growth in humans: a narrative review of the literaure. Clinical Nutrition 2009(28):226-230


Dewey A, Baughan C et al. Eicosapentaenoic acid (EPA, an omega-3 fatty acid from fish oils) for the treatment of cancer cachexia. Cochrane Database of Systematic Reviews 2007, Issue 1. Art. No.: CD004597. DOI:10.1002/14651858.CD004597.pub2


Doornink N, Vogel J et al. Leidraad voor voedingskundigen bij kanker. 4e druk. Haarlem: de Toorts; 2006


Evans, WJ, Morley JE. Cachexia: A new definition. Clinical Nutrition 2008;27:793-799


Heideman WH, Russell NS et al. The frequency, magnitude and timing of post-diagnosis body weight gain in Dutch breast cancer survivors. European Journal of Cancer 2009; 45:119-126 > Voeding en Dieet


Oncology was updated by Niki Doornink, dietician at Academisch Medisch Centrum (AMC), writing also on behalf of the Landelijke Werkgroep Diëtisten Oncologie (LWDO).


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