Oncology Nutrition: Updated Guidelines Discourage Restrictive Diets
Recent updates to clinical practice guidelines are emphasizing the critical role of nutrition in cancer care. The updated S3-Leitlinie “Klinische Ernährung in der Onkologie” – a comprehensive guideline on clinical nutrition in oncology – focuses particularly on the dangers of restrictive diets for individuals undergoing cancer treatment.
The Importance of Nutritional Support
Weight loss is a common and serious consequence of both cancer and its treatment. Maintaining adequate nutrition is therefore paramount, as a patient’s nutritional status directly impacts both the progression of the disease and the effectiveness of therapy. According to Jutta Hübner of Universitätsklinikum Jena, failing to address nutritional deficiencies can lead to “Komplikationen, Therapieversagen und im schlimmsten Fall der Tod durch Mangelernährung” – complications, treatment failure, and, in the worst-case scenario, death from malnutrition.
Critical Evaluation of Special Diets
The updated guidelines assess eleven specific dietary approaches, including vegan, ketogenic, and the so-called Breuß diet. Currently, studies reviewed by the guideline team show no positive benefit from these diets. In fact, the restrictive nature of these diets can actively contribute to malnutrition. While evidence is still lacking regarding vegetarian or vegan diets, the guidelines stress the need for careful planning to avoid deficiencies if patients choose to follow these approaches.
The Risks of Restrictive Diets
The guidelines strongly advise against strict “Krebsdiäten” – cancer diets – and other highly restrictive regimens like fasting, ketogenic diets, and the Budwig and Breuß diets. These diets limit nutritional intake, increasing the risk of malnutrition and weight loss.
Focus on Perioperative Nutrition
A new chapter has been added to the guidelines addressing nutritional needs during and after cancer surgery. The guidelines recommend multiple assessments of a patient’s nutritional status before and after major onco-surgical procedures. Patients unable to consume solid food for several days post-surgery should receive artificial nutrition promptly. For patients at high risk – such as those experiencing significant weight loss – a nutrition therapy plan is recommended even if it means delaying surgery.
Collaborative Development and Funding
The updated guidelines were developed under the leadership of the Deutsche Gesellschaft für Ernährungsmedizin (DGEM), the Deutsche Gesellschaft für Hämatologie und Medizinische Onkologie (DGHO), and the Deutsche Krebsgesellschaft. Forty-three additional professional societies and organizations contributed to the process. The work was financially supported by the Deutsche Krebshilfe.
Frequently Asked Questions
What is the main focus of the updated guidelines?
The main focus is on the importance of adequate nutrition for cancer patients and the critical evaluation of special diets, particularly those that are restrictive.
What does the guideline say about vegan or vegetarian diets?
The guideline states that there is currently insufficient evidence to recommend for or against vegan or vegetarian diets, but careful planning is essential to avoid malnutrition.
What types of diets are specifically discouraged by the guidelines?
The guidelines advise against strict diets such as fasting, ketogenic diets, and the diets after Budwig and Breuß, as they can lead to malnutrition and weight loss.
How might these updated guidelines influence the way healthcare professionals approach nutritional care for cancer patients in the future?