The effect of the ketogenic diet on adult and paediatric patients with primary brain cancers: a systematic review

Abstract

Abstract Background There is growing interest in studying the effects of the ketogenic diet (KD) on cancers. Limited data suggests that the KD limits access to glucose, which may weaken cancer cells that have a high energy demand. The review examines the impact of adults and paediatric patients with brain cancer (BC) using the KD with a specific focus on feasibility, safety and efficacy of prognosis, quality of life (QoL), blood tests and weight outcomes. Methods A systematic search was carried out using PubMed, CENTRAL, Scopus, Ovid and Web of Science databases for relevant literature published in English from 1995–20260. Quantitative observational and interventional studies involving patients with BC following any type of KD were selected. Search words included a combination of BC and KD terms synonyms and abbreviations. The articles were assessed using the National Institute of Health (NIH) quality assessment tools (NHLBI, 2020). Results Fifteen studies (including prospective, retrospective, and case report studies) were eligible for inclusion – seven studies were of good quality, seven of fair quality and one was of poor quality. The studies evaluated different versions of the KD and recruited 173 patients with different BC subtypes. The KD regimens were safely undertaken and well tolerated by 82.6% of patients who completed the studies; however, weight reduction was observed in all studies, with significant weight loss in some. Blood glucose (BG) levels decreased, and ketosis was induced and maintained in most patients. Inconsistent results regarding survival and prognosis were reported. The participants’ QoL assessment was based mainly on questionnaires, which indicated stabilisation or improvement in most studies that evaluated QoL, with few exceptions.

Conclusions The KD has been reported to be safe and well tolerated, and patients who complied with it showed QoL stabilisation; however, the effect on tumour prognosis and survival rates remains inconclusive. Furthermore, weight outcomes were concerning, highlighting the need for patient monitoring by a dietitian while undergoing such a restrictive diet. Future studies are needed to explore the efficacy and optimal regimen that could be better tolerated and provide significant health improvements.