Effects of a ketogenic diet on the quality of life in 16 patients with advanced cancer: A pilot trial

Abstract

Background: Tumor patients exhibit an increased peripheral demand of fatty acids and protein. Contrarily, tumors utilize glucose as their main source of energy supply. Thus, a diet supplying the cancer patient with sufficient fat and protein for his demands while restricting the carbohydrates (CHO) tumors thrive on, could be a helpful strategy in improving the patients' situation. A ketogenic diet (KD) fulfills these requirements. Therefore, we performed a pilot study to investigate the feasibility of a KD and its influence on the quality of life of patients with advanced metastatic tumors.

Methods: Sixteen patients with advanced metastatic tumors and no conventional therapeutic options participated in the study. The patients were instructed to follow a KD (less than 70 g CHO per day) with normal groceries and were provided with a supply of food additives to mix a protein/fat shake to simplify the 3-month intervention period. Quality of life [assessed by EORTC QLQ-C30 (version 2)], serum and general health parameters were determined at baseline, after every two weeks of follow-up, or after drop out. The effect of dietary change on metabolism was monitored daily by measuring urinary ketone bodies.

Results: One patient did not tolerate the diet and dropped out within 3 days. Among those who tolerated the diet, two patients died early, one stopped after 2 weeks due to personal reasons, one felt unable to stick to the diet after 4 weeks, one stopped after 6 and two stopped after 7 and 8 weeks due to progress of the disease, one had to discontinue after 6 weeks to resume chemotherapy and five completed the 3 month intervention period. These five and the one who resumed chemotherapy after 6 weeks report an improved emotional functioning and less insomnia, while several other parameters of quality of life remained stable or worsened, reflecting their very advanced disease. Except for temporary constipation and fatigue, we found no severe adverse side effects, especially no changes in cholesterol or blood lipids.

Conclusions: These pilot data suggest that a KD is suitable for even advanced cancer patients. It has no severe side effects and might improve aspects of quality of life and blood parameters in some patients with advanced metastatic tumors.

Figure 1

Study design. The course of the study plan, including the intervals of data acquisition is shown in this diagram.

Figure 2

Trial profile flow diagram. A trial profile corresponding to the CONSORT criteria is shown indicating the course of the pilot study

Figure 3

Course of urinary ketones. Typical examples of urinary ketone data are shown for three patients reaching ketonuria (A) and three who failed to reach ketonuria on the majority of days (B). The first 50 days of the intervention period are shown

Figure 4

Quality of life. Summary of the EORTC QLQ-C30 (version 2) questionnaires. A): Global health status and functional score remained relatively stable during the time evaluated while the global symptom score increased slightly. B) Subdivision of functional scores shows a slight decrease in physical and role functioning, an increase in emotional functioning and stable cognitive as well as social functioning. C) Concerning digestive functions, the symptoms score showed an increase in appetite loss, constipation or diarrhoea in the first four weeks of the diet. Symptoms then remain stable and signs of diarrhoea diminish. D) The other symptoms were an increase in fatigue and pain corresponding to the very advanced tumor situation. However, insomnia clearly decreased with ongoing dieting. Graphs are given as means for the seven evaluable patients.

Figure 5

Blood parameters. The courses of the blood parameters for the 11 evaluable patients at start of study and after at least 6 weeks of dieting are shown. While the blood glucose (A), creatinine (B), albumin (C) and triglycerides (D) did not change much, leukocyte count increased significantly (E) and cholesterol (F), LDL (G) and LDL/HDL (H) decreased significantly. The patients', ALT dropped significantly (I) while blood urea increased, albeit remaining in normal range (J). Dotted lines: upper and lower level of normal range.