Impact of a ketogenic diet intervention on body composition changes during radiotherapy: Preliminary results of the KETOCOMP study

Background:

Preclinical data indicate that ketogenic diets (KDs) act synergistically with radiation therapy (RT) against tumor cells while protecting against fat free mass loss. We therefore started a phase I trial to study KDs during the course of RT in patients with rectal, head and neck (HN) and breast tumors assigned to one of three groups: (i) a standard diet group; (ii) a ketogenic breakfast group taking up to 50 g MCT oil and 10 g essential amino acids; (iii) a complete ketogenic diet group. Here we report our first preliminary results on body composition changes of all patients prospectively followed using the KETOCOMP study protocol.

Methods:

Body composition was measured prior to and weekly during RT using the seca mBCA bioelectrical impedance analysis (BIA) scale. Blood samples were collected prior to, in the middle of and in the last week of RT. In most cases ketogenic interventions were started following baseline measurements prior to the first RT fraction and lasted until the final week of RT. Longitudinal data were analyzed using linear mixed effects models. For this preliminary analysis, patients receiving a ketogenic breakfast and those on a complete ketogenic diet were grouped together into a single “KD” group in order to increase modeling accuracy.

Results:

A total of 28 (8 KD) rectal, 19 (5 KD) HN and 5 (all KD) breast cancer patients had been followed prospectively. Median beta-hydroxybutyrate (BHB) levels were not significantly different between ketogenic and control patients at baseline (all p > 0.05), but were significantly higher in ketogenic versus control patients during RT (p < 0.001), indicating compliance with the KD. In the breast cancer patients, BHB levels at baseline were significantly lower than during RT (median 0.19 (range 0.03 – 0.27) mmol/l versus 0.56 (0.2 – 2.7) mmol/l, p = 0.021). Regression analysis showed that in rectal cancer patients, KD was not associated with body composition changes, except for a trend of lowering fat mass (p = 0.081). In HN cancer patients chemotherapy (p = 0.012) and irradiated volume (p = 0.088) were associated with fat free mass (p = 0.034) loss, while KD appeared protective (p = 0.027). In the breast cancer patients who had a median BMI of 28.7 kg/m² at baseline, fat mass decreased significantly (p < 0.001), while there was a trend of fat free mass to increase during combined KD+RT (p = 0.081).

Conclusions:

A KD intervention during RT is feasible and may have favorable effects on body composition.