Micronutrientes e capacidade antioxidante em adolescentes sedentários e corredores

Effect of Oral Zinc Supplementation on Phase Angle and Bioelectrical Impedance Vector Analysis in Duchenne Muscular Dystrophy: A Non-Randomized Clinical Trial

Zinc plays a crucial role in cell structure and functionality. Neurodegenerative Duchenne muscular dystrophy (DMD) alters muscle membrane structure, leading to a loss of muscle mass and strength. The objective of this study was to evaluate the changes in phase angle (PA) and bioelectrical impedance vector analysis (BIVA) results in patients with DMD after oral zinc supplementation. This clinical trial included 33 boys aged 5.6 to 24.5 years diagnosed with DMD. They were divided into three groups according to age (G1, G2, and G3) and supplemented with oral zinc. The mean serum zinc concentration was 74 μg/dL, and 29% of patients had concentrations below the reference value. The baseline values (mean (standard deviation)) of the bioelectrical impedance parameters PA, resistance (R), and reactance (Xc) were 2.59° (0.84°), 924.36 (212.31) Ω, and 39.64 (8.41) Ω, respectively. An increase in R and a decrease in PA and lean mass proportional to age were observed, along with a negative correlation (r = -0.614; p < 0.001) between age and PA. The average cell mass in G1 was greater than that in G3 (p = 0.012). There were no significant differences in serum zinc levels or bioelectrical impedance parameters before and after zinc supplementation. We conclude that this population is at risk of zinc deficiency and the proposed dosage of zinc supplementation was not sufficient to alter serum zinc levels, PA and BIVA results.

Zinc in sickle cell disease: A narrative review

Sickle cell disease (SCD) is an inherited disease caused by hemoglobin S mutated hemoglobin S. It is characterized by chronic hemolysis, intermittent vaso-occlusive crises followed by ischemia-reperfusion, and organ damage. These patients have an increased risk of multiple micronutrient deficiencies, such as zinc. The reduced zinc bioavailability in sickle cell patients may lead to several complications such as growth retardation, delayed wound healing, increased vaso-occlusive crises, and infections. This narrative review aims to analyze the literature concerning the zinc status in SCD and their possible consequences on the patients' clinical evolution. We found in children and adolescents a direct association between zinc insufficiencies/deficiencies with increased disease severity in SCD. Monitoring zinc status in children and adolescent SCD appears essential for reducing disease-associated morbidity and infections. Zinc supplementation is a safe therapeutic modality for treating SCD patients. New research must be carried out, especially for adults, to ensure more remarkable survival for this population.

Bioelectrical Impedance Vector Analysis and Phase Angle on Different Oral Zinc Supplementation in Eutrophic Children: Randomized Triple-Blind Study

The parameters derived from bioelectrical impedance, phase angle (PA) and bioelectrical impedance vector analysis (BIVA) have been associated with cell membrane integrity and body cell mass. Zinc is a micronutrient that exerts important structural functions and acts in maintaining cellular functionality. To evaluate cell integrity and body cell mass, PA and BIVA were evaluated in children orally supplemented with zinc at different concentrations. Anthropometric, bioelectrical (resistance and reactance) and serum zinc variables were collected from two randomized, triple-blind, controlled clinical trials. Sampling was composed of 71 children consisting of three groups: a control group who received a placebo and two experimental groups who received oral supplementation of 5 or 10 mg-Zn/day for three months. The three groups presented increases (p < 0.001) in the linear height and weight. In the group supplemented with 10 mg-Zn/day, there was an increase in reactance values (p = 0.036) and PA (p = 0.002), in addition to vector displacement (p < 0.001) in relation to the confidence ellipses. An increase in serum zinc concentration was found (p < 0.001) in all three groups. Whit this, the supplementation with 10 mg-Zn/day promotes changes in the integrity of the cell membrane associated with the increase in the cellular mass of healthy children.

Elevated Serum Retinol and Low Beta-Carotene but not Alpha-Tocopherol Concentrations Are Associated with Dyslipidemia in Brazilian Adolescents

The purpose of this study was to investigate the status of retinol, beta-carotene, and alpha-tocopherol serum concentrations in adolescents with dyslipidemia. A case series dyslipidemia study was conducted, with an attached control group, including 104 adolescents of public schools in Recife during the months of March/April 2013. Retinol, beta-carotene and alpha-tocopherol serum concentrations were analysed by high efficiency liquid chromatography. Sociodemographic, anthropometric, clinical and biochemical variables were analysed. Dyslipidemic adolescents had high serum concentrations of both retinol (p=0.007) and beta-carotene/apolipoprotein A-I ratio (p=0.034); they also had low concentrations of beta-carotene/total cholesterol (p<0.0001) and beta-carotene/apolipoprotein B ratios (p=0.033) when compared to the controls. The alpha-tocopherol serum status was not associated with dyslipidemia. Overweight, abdominal obesity, lipid profile markers, and systolic and diastolic blood pressures were more prevalent in dyslipidemic adolescents. The findings show an association between vitamin A and dyslipidemia in adolescents. However, additional investigations of this risk group are necessary to clarify the mechanisms of action of this nutrient in the pathogenesis of this syndrome, aiming at reducing cardiometabolic risks as of earlier ages.

Designed formulation based on α-tocopherol anchored on chitosan microspheres for pH-controlled gastrointestinal controlled release

Chitosan microspheres were prepared and vitamin E (α-tocopherol) was anchored onto the polymer. The amount of α-tocopherol entrapped onto a gram of the microspheres based system was 13.4±0.4 mg. The microspheres modified with α-tocopherol were applied to vitamin E controlled release in a simulated gastrointestinal system. Characterizations were carried out by optical microscopy, FTIR and HPLC-UV techniques. For chitosan microspheres based system there was a 4.10% release, while for pure α-tocopherol the release was 25.53%. The percentage of α-tocopherol released at pH 6.8 was 13.10% for chitosan microspheres and 60.00% for free α-tocopherol. At pH 7.4, α-tocopherol release reached 51.30% and 92.88% for chitosan microspheres and pure α-tocopherol, respectively. α-tocopherol immobilized onto chitosan presented three distinct landings at each studied pH, whereas pure α-tocopherol presented only two established solubilization regions, one at pH 1.2, while between pH 6.8 and 7.4 it did not present any difference, establishing after 3.5h. Thus, the immobilization of α-tocopherol onto chitosan microspheres figures it as an efficient controlled release system.

Aspectos sobre a relação entre exercício físico, estresse oxidativo e zinco

Este trabalho visa a contribuir com informações sobre a relação entre exercício físico, estresse oxidativo e zinco. A formação de espécies reativas de oxigênio durante o exercício pode contribuir para danos tissulares e celulares, prejudicando o desempenho do atleta. Podem amenizar esses efeitos alguns minerais, como o zinco, que atuam como cofator da enzima superóxido dismutase e na regulação da síntese da metalotioneína, proteínas importantes no sistema de defesa antioxidante. No exercício físico, ocorrem distúrbios na compartimentalização do zinco, com alterações da concentração desse mineral em compartimentos celulares. No entanto, os mecanismos envolvidos no comportamento metabólico do zinco bem como a participação do mineral na melhora do desempenho físico ainda não estão totalmente esclarecidos. Dessa forma, conclui-se que a distribuição do zinco em organismos submetidos ao estresse oxidativo e os efeitos da deficiência desse mineral na capacidade antioxidante durante o exercício ainda devem ser pesquisados mais profundamente.