Evaluation of Acute Supplementation With the Ketone Ester ( R )-3-Hydroxybutyl-(R)-3-Hydroxybutyrate (deltaG) in Healthy Volunteers by Cardiac and Skeletal Muscle 31 P Magnetic Resonance Spectroscopy.

In this acute intervention study, we investigated the potential benefit of ketone supplementation in humans by studying cardiac phosphocreatine to adenosine-triphosphate ratios (PCr/ATP) and skeletal muscle PCr recovery using phosphorus magnetic resonance spectroscopy ( ³¹ P-MRS) before and after ingestion of a ketone ester drink. We recruited 28 healthy individuals: 12 aged 23-70 years for cardiac ³¹ P-MRS, and 16 aged 60-75 years for skeletal muscle ³¹ P-MRS. Baseline and post-intervention resting cardiac and dynamic skeletal muscle ³¹ P-MRS scans were performed in one visit, where 25 g of the ketone monoester, deltaG ^® , was administered after the baseline scan. Administration was timed so that post-intervention ³¹ P-MRS would take place 30 min after deltaG ^® ingestion. The deltaG ^® ketone drink was well-tolerated by all participants. In participants who provided blood samples, post-intervention blood glucose, lactate and non-esterified fatty acid concentrations decreased significantly (-28.8%, p ≪ 0.001; -28.2%, p = 0.02; and -49.1%, p ≪ 0.001, respectively), while levels of the ketone body D-beta-hydroxybutyrate significantly increased from mean (standard deviation) 0.7 (0.3) to 4.0 (1.1) mmol/L after 30 min ( p ≪ 0.001). There were no significant changes in cardiac PCr/ATP or skeletal muscle metabolic parameters between baseline and post-intervention. Acute ketone supplementation caused mild ketosis in blood, with drops in glucose, lactate, and free fatty acids; however, such changes were not associated with changes in ³¹ P-MRS measures in the heart or in skeletal muscle. Future work may focus on the effect of longer-term ketone supplementation on tissue energetics in groups with compromised mitochondrial function.
Competing Interests: RS is employed by GE Healthcare. The intellectual property covering the uses of ketones and ketone esters is owned by BTG Ltd., the University of Oxford, the National Institutes of Health, and TΔS Ltd. Should royalties ever accrue from these patents, KC, as an inventor, will receive a share of the royalties under the terms proscribed by Oxford University. KC is a director of TΔS Ltd., a company spun out of the University of Oxford to develop and commercialise products based on the science of ketone bodies in human nutrition. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2022 Cameron, Soto-Mota, Willis, Ellis, Procter, Greenwood, Saunders, Schulte, Vassiliou, Tyler, Schmid, Rodgers, Malcolm, Clarke, Frenneaux and Valkovič.)