Seven-day overfeeding enhances adipose tissue dietary fatty acid storage and decreases myocardial and muscle dietary fatty acid partitioning in healthy subjects
Résumé
BACKGROUND: Increased myocardial partitioning of dietary fatty acids (DFA) and decreased left-ventricular (LV) function is associated with insulin resistance in prediabetes. OBJECTIVE: We hypothesized that enhanced myocardial DFA partitioning and reduced LV function may be induced concomitantly with reduced insulin sensitivity upon a 7-day hypercaloric (+50% in caloric intake), high saturated fat (~11% of energy) and simple carbohydrates (~54% of energy) diet (HIGHCAL) vs. an isocaloric diet (ISOCAL) with a moderate amount of saturated fat (~8% of energy) and carbohydrates (~50% of energy). DESIGN: Thirteen healthy subjects (7 men/6 women) underwent HIGHCAL vs. ISOCAL in a randomized crossover design, with organ-specific DFA partitioning and LV function measured using the oral 14(R,S)-[(18)F]-fluoro-6-thia-heptadecanoic acid and [(11)C]-acetate positron emission tomography methods at the end of both interventions. RESULTS: HIGHCAL induced a decrease in insulin sensitivity indexes with no significant change in body composition. HIGHCAL led to increased subcutaneous abdominal (+4.2+/-1.6 %, P\textless0.04) and thigh (+2.4+/-1.2 %, P\textless0.08) adipose tissue storage and reduced cardiac (-0.31+/-0.11 mean standard uptake value [SUV], P\textless0.03) and skeletal muscle (-0.17+/-0.08 SUV, P\textless0.05) DFA partitioning without change in LV function. CONCLUSIONS: We conclude that early increase in adipose tissue DFA storage protects the heart and skeletal muscles from potential deleterious effects of DFA.