Ketogenic diets consumed during radio-chemotherapy have beneficial effects on quality of life and metabolic health in patients with rectal cancer

Purpose Interest in ketogenic diets (KDs) as complementary nutritional treatments for cancer patients is rising, although some skepticism about their safety exists. We, therefore, studied the effects of KDs on quality of life and blood parameters in rectal cancer patients undergoing radio-chemotherapy. Methods EORTC-QLQ30 questionnaire scores and different metabolic and hormonal blood parameters were obtained prior to, in the middle of and at the end of radiotherapy within the KETOCOMP study (ClinicalTrials.gov Identifier: NCT02516501). A total of 18 patients consuming a KD were compared to 23 patients consuming their standard diet (SD). Baseline-end differences were measured using Wilcoxon tests, and repeated measures analysis was performed using linear mixed effects models. Results Eighty-nine percent of patients on the KD reported subjectively feeling good or very good, but roughly half of them rated the daily routine implementation as difficult. Only the SD group experienced significant declines in physical and role functioning, while the KD group improved in role ( p = 0.045), emotional ( p = 0.018) and social functioning ( p = 0.009).Urinary frequency, buttock pain and fatigue significantly increased in the SD group, but to a much lesser extent in the KD group. Several biomarkers of metabolic health (gamma-glutamyl-transpeptidase, triglyceride-glucose index, HDL cholesterol/triglyceride ratio, and free T3) improved in the KD, but not the SD group. Conclusions Despite being perceived as difficult to implement by ≈50% of patients, KDs are feasible as complementary therapies alongside radio-chemotherapy and associated with subjective well-being. The hypothesis that they exert beneficial effects on quality of life and metabolic health in rectal cancer patients is supported by our data. Trial registration ClinicalTrials.gov identifier NCT02516501, registered Aug 6th 2015.