From the Guidelines
The ketogenic diet should not be considered a replacement for standard cancer treatments, and its use as a complementary approach should be carefully weighed against potential risks and benefits, particularly in terms of nutritional adequacy and potential interactions with cancer therapies 1.
Background
The idea that a ketogenic diet might slow cancer growth by restricting glucose has some scientific basis, as cancer cells typically rely heavily on glucose for energy (known as the Warburg effect), while normal cells can adapt to use ketones for fuel when glucose is limited.
- Some laboratory and animal studies suggest this metabolic shift may slow the growth of certain cancer types.
- However, not all cancers respond the same way, as some can adapt to use ketones or other fuels.
Clinical Evidence
The most recent and highest quality study on this topic, published in 2022, found that there are exceedingly few randomized controlled trials (RCTs) testing the effect of specific diets, eating patterns, or foods during cancer treatment on cancer or patient-reported outcomes 1.
- The limited data currently available do not support a benefit of dietary modification during treatment on fatigue, quality of life, or other patient-reported outcomes.
- Additionally, studies have suggested that patients randomly assigned to ketogenic diets express lower levels of dietary satisfaction compared with patients randomly assigned to control or other dietary interventions.
Recommendations
Given the limited evidence and potential risks, the ketogenic diet should be approached with caution and only considered under the guidance of a healthcare provider.
- It is essential to prioritize nutritional adequacy and ensure that any dietary modifications do not compromise the patient's overall health or interact with cancer therapies.
- Further research is needed to fully understand the potential benefits and risks of the ketogenic diet in cancer treatment.
From the Research
Cancer Cell Growth and Ketogenic Diet
- The idea of starving cancer cells from glucose by doing the keto diet to prevent them from growing as fast is based on the Warburg effect, which states that cancer cells predominantly use glucose anaerobically 2.
- Studies have investigated the use of ketogenic diets in cancer patients, with some suggesting potential benefits, but the evidence is inconsistent and limited by poor quality and heterogeneity 3, 2, 4.
- A systematic review and meta-analysis of randomized controlled trials found that the ketogenic diet led to decreased glucose levels in patients with cancer, but did not show significant improvements in other cancer-related variables such as cholesterol, insulin-like growth factor 1, weight, or quality of life 5.
Mechanisms and Effects of Ketogenic Diet
- The therapeutic mechanisms of action of the ketogenic diet may potentially influence cancer treatment and prognosis by targeting cancer cell metabolism 2.
- However, the current evidence is not conclusive, and high-quality studies are needed to fully evaluate the effects of the ketogenic diet on cancer-related outcomes 3, 4, 5.
- Medical oncologists in Canada have expressed concerns about the use of ketogenic diets in patients with cancer, citing unknown efficacy and potential side effects 6.
Adherence and Practicality
- Adherence to the ketogenic diet is often low, ranging from 23.5% to 100% in studies, which can affect the validity of the results 4.
- The role of registered dietitian nutritionists is crucial in planning and implementing ketogenic diet protocols in oncology research settings to ensure patients' adherence and optimal nutritional status 2.