A growing body of evidence indicates the importance of nutrition in cancer treatment. Ketogenic diets are one of the strategies that have been proposed to enhance traditional anti-cancer therapy. This review summarises the evidence on the effect of oral ketogenic diets on anthropometry, metabolism, quality of life (QoL) and tumour effects whilst documenting adverse events and adherence in patients with cancer.
We searched electronic databases using medical subject headings (MeSH) and text words related to ketogenic diets and cancer. Adult patients following a ketogenic diet as a complementary therapy prior, alongside or after standard anti-cancer treatment for longer than 7-days were included. Studies were assessed for quality using the Critical Appraisal Skills Programme tools.
Eleven studies were included with 102 participants, (age range 34-87 years) from early phase trials, cohort studies and case reports. Studies included participates with brain, rectal or mixed cancer sites with early or advanced disease stage. The duration of intervention ranged from 2.4-134.7 weeks (0.5-31 months). Evidence was inconclusive for nutritional status and adverse events. Mixed results were observed for blood parameters, tumour effects and QoL. Adherence to diet was low (50 out of 102, 49%) and ranged from 23.5-100%.
High-quality evidence on the effect of ketogenic diets on anthropometry, metabolism, QoL and tumour effects is currently lacking in oncology patients. Heterogeneity between studies and low adherence to dietary manipulation impedes the current evidence. There is an obvious gap in the evidence highlighting a need for controlled trials to fully evaluate the intervention.