Purpose of review To discuss the technique and clinical applications of myocardial and hepatic H magnetic resonance spectroscopy to study myocardial and hepatic triglyceride content, in relation to changes in plasma nonesterified fatty acids induced by nutritional interventions. Recent findings Progressive caloric restriction induces a dose-dependent increase in myocardial triglyceride content and a dose-dependent decrease in diastolic function in lean healthy men. Hepatic triglyceride content shows a differential response to progressive caloric restriction, indicating that redistribution of endogenous triglyceride stores is tissue specific, at least in lean healthy men. A short-term high-fat high-energy diet in healthy men results in major increases in hepatic fat content, whereas it does not influence myocardial triglyceride content or myocardial function. Apparently, there is a differential, tissue-specific partitioning of either triglyceride or fatty acids or both between nonadipose organs such as the human heart and liver during different physiological conditions. Summary Metabolic MRI of myocardial and hepatic triglyceride content is a promising new tool to study the effects of nutritional interventions on myocardial and hepatic lipid metabolism in relation to heart function. Future studies should aim to apply these magnetic resonance techniques to obesity and type 2 diabetes mellitus.
