This low sensitivity can be overcome using the recent development of hyperpolarized magnetic resonance (MR) technology, which can amplify the 13C MRS signal by over 10 000-fold.12 Using hyperpolarized [1-13C]pyruvate, physiological changes in PDH flux have been demonstrated in animal models of feeding and fasting.13–15 In addition, changes in cardiac substrate selection in a variety of pathological situations have been observed,16–18 particularly in diabetes mellitus.7,14,19,20. Here, PDP1 is linked to diabetes mellitus.