Need for New Review of Article on Ketogenic Dietary Regimes for Cancer Patients

This 2017 comment offers a rebuttal to a review from earlier that year by Nicole Erickson et al., “Systematic review: Isocaloric ketogenic dietary regimes for cancer patients.” Erickson et al. argue the evidence supporting the use of ketogenic diets for cancer treatment is lacking; the authors of the rebuttal argue the evidence is merely preliminary and, in fact, the existing evidence is promising.

The ketogenic diet, the comment authors argue, can only be assessed in comparison to existing cancer treatments. For the majority of cancers, standard-of-care treatments (i.e., radiotherapy and chemotherapy) have limited efficacy and significant side effects. Within this context, even preliminary evidence the ketogenic diet may be effective, either as an individual treatment or as part of a combination therapy, is worth interest and further research.

The ketogenic diet, they argue, functions as an effective cancer therapy through multiple mechanisms. Ketogenic diets reduce energy availability to tumors. They also increase the generation of reactive oxygen species and the vulnerability of tumors to oxidative damage. Simultaneously, they have been shown to attenuate the negative effects of chemo- and radiotherapy. These factors make a ketogenic diet particularly potent in combination with other cancer therapies.

The risks associated with a ketogenic diet are limited. A ketogenic diet may lead to weight loss, but the weight lost is primarily water weight associated with a loss of glycogen. The ketogenic diet has, in fact, been shown to reduce risk of cachexia (i.e., harmful loss of protein/muscle mass). Similarly, acidosis, hypoglycemia, and nutritional inadequacy are not true risks of a well-structured ketogenic diet. In fact, the existing literature suggests many of the negative effects attributed to the use of a ketogenic diet during cancer treatment may in fact be side effects of other adjuvant therapies, and the ketogenic diet, if anything, improves quality of life and reduces side effects in cancer patients undergoing chemotherapy and radiotherapy.

Multiple studies have shown the ketogenic diet is highly effective as an adjuvant to other treatments and leads to an extraordinary response in some patients. In light of this and the aforementioned factors, the authors argue the lack of evidence currently supporting the use of a ketogenic diet for cancer therapy does not reflect its lack of efficacy but merely results from the preliminary but rapidly advancing state of keto research.

The authors close by posing a broader ethical question. Erickson et al. have neither clinical nor research experience with the use of ketogenic diets in cancer therapy; as such, it is valid to question whether they have the expertise necessary to render judgment on the diet’s value. The fact that such a review, written by these authors, could be published may indicate the need for more rigorous standards for the content and authorship of review papers to ensure reviews provide fair assessments of the current state of the science.

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Notes

1. Ketogenic diets as an adjuvant cancer therapy: History and potential mechanism; Insulin, carbohydrate restriction, metabolic syndrome and cancer; Role of ketogenic metabolic therapy in malignant glioma: a systematic review; Metabolic therapy: a new paradigm for managing malignant brain cancer.
2. Modified Atkins diet in advanced malignancies: Final results of a safety and feasibility trial within the Veterans Affairs Pittsburgh Healthcare System; Metabolic response to feeding in weight-losing pancreatic cancer patients and its modulation by a fish-oil-enriched nutritional supplement; Metabolic reprogramming induced by ketone bodies diminishes pancreatic cancer cachexia.
3. Ketogenic diets as an adjuvant cancer therapy: history and potential mechanism; The ketogenic diet is an effective adjuvant to radiation therapy for the treatment of malignant glioma; Impact of a ketogenic diet intervention during radiotherapy on body composition: I. Initial clinical experience with six prospectively studied patients.
4. Modified Atkins diet in advanced malignancies: final results of a safety and feasibility trial within the Veterans Affairs Pittsburgh Healthcare System; Effects of a ketogenic diet on tumor metabolism and nutritional status in pediatric oncology patients: Two case reports; The development of tumours under a ketogenic diet in association with the novel tumour marker TKTL1: A case series in general practice.