Effects of Vitamin D Supplefmentation on Outcome of Low-Calorie Diet in Workers Presenting Obesity or Overweight: A Retrospective Observational Study.

AIM: Growing evidence underscores the inverse association between serum vitamin D (vit D) and chronic conditions such as metabolic syndrome, diabetes and obesity. The aim of this retrospective study was to compare weight loss and metabolic serum biomarkers in subjects on low-calorie diet receiving vit D supplementation versus those not receiving it. METHODS: The study considered 405 indoor sedentary workers with overweight/obesity and vit D insufficiency, who participated to a health fitness program between 2011-2013. Participants were recommended a moderately-low calorie diet plus vit D supplementation with 150,000 or 900,000 IU cumulative over 6 months in case of hypovitaminosis D (according to the guidelines at the enrollment), while those with optimal levels were recommended only diet. Participants were evaluated at baseline (T0), and after 6 months (T1). Anthropometric parameters, BMI, waist circumference (WC), serum 25-hydroxyvitamin D concentration ([25(OH)D]) and glycated hemoglobin (HbA1c) were assessed at T0 and T1. RESULTS: Participants fell into one of three groups: (A) not supplemented, (B) receiving 150,000 IU and (C) receiving 900,000 IU cumulative over 6 months. Overall, the supplementation was associated with increased [25(OH)D], but only the dosage of group C was associated with the achievement of optimal vit D status. A significantly greater weight decrease was observed in group B (-4.1 kg) and C (-4.5 kg) compared to untreated (-1.2 kg). WC reduction was higher in the vit D groups (group B: -3.95 cm; group C; -6.20 cm; untreated: -3.21 cm; p < 0.05). When setting the threshold for obesity at BMI > 30kg/m2, [25(OH)D] no longer correlated with body fat or weight. [25(OH)D] inversely correlated with the Homeostatic Model Assessment for Insulin Resistance and remained significant after adjustment for BMI. CONCLUSIONS: Higher [25(OH)D] levels were associated to a greater weight loss and enhanced the beneficial effects of a reduced-calorie diet in individuals with BMI > 30 kg/m2.

Supplementation with a selective amino acid formula ameliorates muscular dystrophy in mdx mice.

Duchenne muscular dystrophy (DMD) is one of the most common and severe forms of muscular dystrophy. Oxidative myofibre content, muscle vasculature architecture and exercise tolerance are impaired in DMD. Several studies have demonstrated that nutrient supplements ameliorate dystrophic features, thereby enhancing muscle performance. Here, we report that dietary supplementation with a specific branched-chain amino acid-enriched mixture (BCAAem) increased the abundance of oxidative muscle fibres associated with increased muscle endurance in dystrophic mdx mice. Amelioration of the fatigue index in BCAAem-treated mdx mice was caused by a cascade of events in the muscle tissue, which were promoted by endothelial nitric oxide synthase (eNOS) activation and vascular endothelial growth factor (VEGF) expression. VEGF induction led to recruitment of bone marrow (BM)-derived endothelial progenitors (EPs), which increased the capillary density of dystrophic skeletal muscle. Functionally, BCAAem mitigated the dystrophic phenotype of mdx mice without inducing dystrophin protein expression or replacing the dystrophin-associated glycoprotein (DAG) complex in the membrane, which is typically lost in DMD. BCAAem supplementation could be an effective adjuvant strategy in DMD treatment.