Proceedings of The Physiological Society

The Biomedical Basis of Elite Performance 2016 (London, UK) (2016) Proc Physiol Soc 35, PC12

Poster Communications

Ketone ester drinks increase blood ketone levels more effectively than ketone salt drinks

B. J. Stubbs1, R. Evans1, K. Clarke1, P. J. Cox1

1. Department of Physiology Anatomy and Genetics, Oxford University, Oxford, United Kingdom.

Introduction: Ketone bodies (KB) are oxidative fuel substrates and metabolic signals produced in response to starvation or a high fat, low carbohydrate diet. KB may provide a superior fuel source to athletes [1]. We developed a ketone ester (KE) that, when consumed as a drink, rapidly increased circulating KB [2]. Ketone salt (KS) drinks are an alternative to achieve nutritional ketosis [3]. However, the comparative efficacy of KE and KS drinks to raise blood KB is unknown. The aim of this study was to compare blood KB levels after body-weight adjusted, equimolar amounts of KB were consumed in KE and KS drinks. Methods and Results: Following favourable ethical review, healthy, non-obese volunteers (n = 5) completed a 4-armed randomized, cross-over study. Following an overnight fast, volunteers consumed a weight-adjusted dose of β-hydroxybutyrate (BHB) (low- 1.6 mmol/kg OR high- 3.2 mmol/kg) in KS or KE, artificially flavoured and made up to 300 ml using water. Blood samples were obtained via an IV catheter at baseline (BL) and at regular intervals post-drink. Samples were analyzed for D-BHB. Volunteers completed questionnaires to record any GI/systemic symptoms experienced. D-BHB values are means ± SEM. Symptoms are number reported per 100 possible reports. Repeated measures ANOVA with Tukey Post Hoc corrections were performed. Significance was taken at p<0.05. Consumption of both KE and KS drinks increased the blood levels of D-BHB. Peak D-BHB concentration (D-BHB Cmax) was significantly greater following the high dose of KE (3.0 ± mM) vs. low dose KE (1.5 ± mM) and vs. both high (1.2 ± mM) and low (0.9 ± mM) doses of KS. There were no significant differences in D-BHB Cmax between low dose KE, and low and high doses of KS. D-BHB uptake (AUC) was significantly higher following high dose of KE (417 ± 62 mM.min) vs. all other groups, but there were no differences between low dose KE (166 ± 24 mM.min), and low (117 ± 21 mM.min) and high (170 ± 7 mM.min) doses of KS. GI symptoms reported were significantly higher with high dose of KS (10/100 possible) than low doses of both KS (2.6/100 possible) and KE (3.4/100 possible), however there were no significant differences between the high dose of KE (6.5/100 possible) and all other groups. Conclusions: Increasing KE dose results in greater D-BHB Cmax and AUC; however this is not seen following KS drinks. Long term KS consumption may result in clinical complications due to the inorganic ion load in each drink [4], furthermore we saw that high doses of KS cause a greater incidence of GI symptoms. Therefore we conclude that KE drinks are a more effective method to elevate D-BHB in athletes than KS drinks, with fewer acute side effects.

Where applicable, experiments conform with Society ethical requirements