EVALUATION OF ZINC SUPPLEMENTATION ON PHASE ANGLE AND VECTOR ANALYSIS OF BIOELECTRICAL IMPEDANCE IN BOYS WITH DUCHENNE MUSCULAR DYSTROPHY: A CLINICAL TRIAL
Rare disease; Electric Impedance; body composition; micronutrients; pediatrics
Background: Duchenne muscular dystrophy (DMD) is a neurodegenerative disease that alters the structure of the muscle plasma membrane with a consequent progressive loss of muscle mass and strength. Zinc plays a crucial role in cell structure and functionality; its supplementation has a modifying effect on the phase angle (PA) and on the bioimpedance vector analysis (BIVA) of healthy children. Aim: To evaluate changes in PA and BIVA in boys with DMD after oral zinc supplementation. Design: This clinical trial was carried out from February 2018 to March 2020 with boys diagnosed with DMD. These were divided into three groups (G1, G2, and G3) and received oral supplementation of 5, 10, or 15 mg of zinc. Before and after supplementation, data were collected: serum zinc, anthropometric data, and bioelectrical impedance (BIA). Results: 33 boys aged between 5.6 and 24.5 years were analyzed. The mean serum zinc concentration was 74 μg / dL and 29% had concentrations below the reference value. The mean (SD) of the BIA parameters were: PA = 2.59° (0.84); R = 924.36 (212.31) 𝛺; Xc = 39.64 (8.41) 𝛺. We verified an increase in resistance and a decrease in PA and free fat mass proportional to age, in addition to a negative correlation (r = -0.614; p < 0.001) between age and PA. Regarding BIVA, we found a greater cell mass in G1 when compared to G3 (p = 0.012). Conclusion: The research participants were at risk of zinc deficiency, and zinc supplementation, at the dosages that were used, was not sufficient to change the parameters of serum zinc, PA, and BIVA in the study population. However, PA and BIVA are useful parameters for the clinical-nutritional evaluation and follow-up of boys with DMD.