Effects of a leucine‐containing nutraceutical on fat oxidation in overweight and obese adults

Abstract

We have previously shown leucine to modulate energy partitioning between adipose tissue and myocytes by suppressing adipocyte lipid storage, increasing myocyte fatty acid oxidation and stimulating mitochondrial biogenesis in both cell types. Consequently, we have now evaluated the efficacy of a nutraceutical preparation (InnutriaTM) containing 2.25 g leucine/d in 3 daily doses on fat oxidation. 20 overweight and obese subjects were randomized to receive Innutria‐supplemented or control tea three times/day for 28 days. All subjects maintained their usual diets and modestly increased their physical activity by walking (steps increased from baseline 3882+713 steps/day to 8406+925 steps/day during treatment; no difference between groups). Respiratory quotient (RQ) and fat oxidation were assessed by respiratory gas exchange on day 0 and day 28. There were no significant changes in RQ or fat oxidation in the control group (RQ change, 0.011; fat oxidation change, ‐0.23+0.28 g/hr, ‐5.6 g/d, NS), while the supplemented group exhibited a decrease in RQ (‐0.019, p<0.04) and a corresponding increase in fat oxidation (+1.4+0.4 g/hr, 33.6 g/d, p<0.01). These data demonstrate that a nutraceutical blend containing leucine effectively increases fat oxidation and may thereby contribute to weight management in overweight and obese subjects.