Goodpaster, Bret H.

AbstractBackgroundObservational reports suggest that supplementation that increases citric acid cycle intermediates via anaplerosis may have therapeutic advantages over traditional medium‐chain triglyceride (MCT) treatment of long‐chain fatty acid oxidation disorders (LC‐FAODs) but controlled trials have not been reported. The goal of our study was to compare the effects of triheptanoin (C7), an anaplerotic seven‐carbon fatty acid triglyceride, to trioctanoin (C8), an eight‐carbon fatty acid triglyceride, in patients with LC‐FAODs.MethodsA double blinded, randomized controlled trial of 32 subjects with LC‐FAODs (carnitine palmitoyltransferase‐2, very long‐chain acylCoA dehydrogenase, trifunctional protein or long‐chain 3‐hydroxy acylCoA dehydrogenase deficiencies) who were randomly assigned a diet containing 20% of their total daily energy from either C7 or C8 for 4 months was conducted. Primary outcomes included changes in total energy expenditure (TEE), cardiac function by echocardiogram, exercise tolerance, and phosphocreatine recovery following acute exercise. Secondary outcomes included body composition, blood biomarkers, and adverse events, including incidence of rhabdomyolysis.ResultsPatients in the C7 group increased left ventricular (LV) ejection fraction by 7.4% (p = 0.046) while experiencing a 20% (p = 0.041) decrease in LV wall mass on their resting echocardiogram. They also required a lower heart rate for the same amount of work during a moderate‐intensity exercise stress test when compared to patients taking C8. There was no difference in TEE, phosphocreatine recovery, body composition, incidence of rhabdomyolysis, or any secondary outcome measures between the groups.ConclusionsC7 improved LV ejection fraction and reduced LV mass at rest, as well as lowering heart rate during exercise among patients with LC‐FAODs.Clinical Trial Registration: Clinicaltrials.gov NCT01379625.

ObjectiveTo determine effects of physical activity (PA) with diet‐induced weight loss on energy metabolism in adults with severe obesity.MethodsAdults with severe obesity (n = 11) were studied across 6 months of intervention, then compared with controls with less severe obesity (n = 7) or normal weight (n = 9). Indirect calorimetry measured energy metabolism during exercise and rest. Markers of muscle oxidation were determined by immunohistochemistry. Data were presented as medians.ResultsThe intervention induced 7% weight loss (P = 0.001) and increased vigorous PA by 24 min/wk (P = 0.02). During exercise, energy expenditure decreased, efficiency increased (P ≤ 0.03), and fatty acid oxidation (FAO) did not change. Succinate dehydrogenase increased (P = 0.001), but fiber type remained the same. Post‐intervention subjects’ resting metabolism remained similar to controls. Efficiency was lower in post‐intervention subjects compared with normal‐weight controls exercising at 25 W (P ≤ 0.002) and compared with all controls exercising at 60% VO2peak (P ≤ 0.019). Resting and exercise FAO of post‐intervention subjects remained similar to adults with less severe obesity. Succinate dehydrogenase and fiber type were similar across all body weight statuses.ConclusionsWhile metabolic adaptations to PA during weight loss occur in adults with severe obesity, FAO does not change. Resulting FAO during rest and exercise remains similar to adults with less severe obesity.