Effects of a Leucine and Pyridoxine-Containing Nutraceutical on Fat Oxidation, and Oxidative and Inflammatory Stress in Overweight and Obese Subjects

Michael B Zemel,Antje Bruckbauer

doi:10.3390/nu4060529

Michael B Zemel, Antje Bruckbauer

Open Access

https://doi.org/10.3390/nu4060529

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Journal: Nutrients	Publication Date: Jun 15, 2012
Citations: 88	License type: CC BY 3.0

Affiliation: University of Tennessee at Knoxville

Abstract

Leucine stimulates tissue protein synthesis and may also attenuate adiposity by increasing fatty acid oxidation and mitochondrial biogenesis in muscle and adipocytes. Accordingly, the effects of a nutraceutical containing 2.25 g leucine and 30 mg pyridoxine (Vitamin B6) (NuFit active blend) were tested in cell culture and in a clinical trial. 3T3L1 adipocytes were treated with leucine (0.25 mM or 0.5 mM) and/or Pyridoxal Phosphate (PLP) (50 nM or 100 nM) for 48 h. For the clinical trial, twenty overweight or obese subjects received the NuFit active blend or placebo three times/day for 4 weeks without energy restriction. Leucine decreased fatty acid synthase (FAS) expression and triglyceride content in adipocytes, and PLP addition significantly augmented this effect. Administration of NuFit active blend in the clinical trial increased fat oxidation by 33.6 g/day (p < 0.04), decreased respiratory quotient, improved HOMAIR, reduced oxidative and inflammatory biomarkers (plasma MDA, 8-isoprostane-F2α, TNF-α, C-reactive protein), and increased the anti-inflammatory marker adiponectin. These data indicate that the NuFit active blend significantly increased fat oxidation and insulin sensitivity, and reduced oxidative and inflammatory stress. Therefore, the NuFit active blend appears to be a useful nutraceutical in the management of obesity and associated co-morbidities.

Highlights

Leucine ingestion is well recognized to stimulate tissue protein synthesis via both mTOR-dependent and -independent pathways [1], as well as exerting an antiproteolytic effect [2]
The NuFit active blend is a blend of leucine and pyridoxine which we propose to be more effective than leucine alone in regulating energy metabolism
Leucine reduced both the expression and activity of fatty acid synthase (FAS) in adipocytes by 61 and 54%, respectively, and these effects were significantly augmented by the addition of Pyridoxal Phosphate (PLP) to 82 and 67%, respectively

Summary

Introduction

Leucine ingestion is well recognized to stimulate tissue protein synthesis via both mTOR-dependent and -independent pathways [1], as well as exerting an antiproteolytic effect [2]. These effects predominate in muscle, but are manifested in other tissues, including adipose tissue [3]. Treatment of muscle cells with adipocyte conditioned medium attenuates fatty acid oxidation in muscle indicating that adipocyte secreted factor(s) suppress these effects, while leucine administration permits a partial escape from this suppression [9,10]

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