Nutritional status of selenium in overweight and obesity: A systematic review and meta-analysis.

BACKGROUND & AIMS: Selenium is an antioxidant and anti-inflammatory nutrient and regulates important physiological processes, such as carbohydrate and lipid metabolism, immune system actions, and adipocyte differentiation. Given these important functions, several studies have assessed the nutritional status of selenium to elucidate whether its homeostasis is impaired by excess adiposity, which in turn could contribute to the adipose tissue dysfunction and metabolic disorders. However, the results of these studies are quite controversial. Therefore, this systematic review and meta-analysis aimed to assess differences in the nutritional status of selenium in overweight/obese individuals. METHODS: We searched the PubMed, Scopus, Web of Science, Embase, Cochrane Library, and Virtual Health Library databases. Studies comparing overweight or obese individuals with eutrophic individuals and assessing at least one marker of selenium were included. Comprehensive Meta-Analysis software was used to perform meta-analysis. The effect size was calculated using the raw mean difference or the standardized mean difference, with 95% confidence interval and a p-value of <0.05. Heterogeneity was determined using the I2 index. Subgroup analyses were performed according to sex, body mass index (BMI), and selenium content in the soil. The protocol of this review was registered in the Prospective Register of Systematic Reviews (registration number: CRD42020185405). RESULTS: This systematic review included 73 articles, of which 65 articles were eligible for meta-analysis. There were no significant differences between the overweight/obesity and eutrophy groups in terms of dietary intake and plasma/serum levels of selenium and selenoprotein P levels. The activity of plasma/serum glutathione peroxidase was decreased in the overweight/obese children and adolescents; however, the difference was no statistically significant when the enzyme activity was analyzed in erythrocytes and whole blood. In the adult age group, overweight/obese individuals had decreased activity of both glutathione peroxidase isoforms compared to those individuals with eutrophy. In particular, the activity of erythrocyte glutathione peroxidase was significantly decreased in obese individuals and those living in regions with low-to-moderate selenium content in the soil. Regarding selenium excretion markers, overweight/obese individuals had lower levels of selenium in the urine and nails and a trend of higher levels of selenium in the hair than eutrophic individuals. CONCLUSIONS: In conditions of excess adiposity, the main alteration in the nutritional status of selenium is a decrease in glutathione peroxidase activity, particularly in adults with obesity. In addition, reduced levels of selenium in urine and nails can be found in overweight or obese individuals.

Association between calcium/magnesium ratio and insulin resistance in women with obesity and normal-weight women

ABSTRACT The aim of this study was to evaluate the association between the calcium/magnesium (Ca/Mg) ratio and insulin resistance in women with obesity and normal-weight women. This was a cross-sectional study with 128 women (62 women with obesity and 66 normal-weight women). We measured dietary minerals intake and analyzed magnesium and calcium biomarkers. Ca/Mg ratio in diet, plasma and urine were calculated. We have evaluated glycemic parameters. Women with obesity had low dietary magnesium, reduced plasma and erythrocyte magnesium concentrations, and elevated urinary magnesium excretion. Plasma calcium concentration was lower and urinary calcium excretion was higher in patients with obesity than in the normal-weight group. Dietary magnesium and calcium intake per kilogram of body weight per day was lower in obese women than in the control group. Ca/Mg ratio in plasma and urine were elevated in women with obesity. We found a significant correlation among magnesium biomarkers and calcium parameters. Ca/Mg ratio seems to be associated with insulin resistance in obese women.

RESUMEN El objetivo de este estudio fue evaluar la asociación entre la relación Ca/Mg y la resistencia a la insulina en mujeres con obesidad y en mujeres con peso normal. El diseño del estudio fue transversal y participaron 128 mujeres (62 mujeres con obesidad y 66 mujeres con peso normal). Se analizó la ingesta de minerales en la dieta y se realizaron análisis de biomarcadores de magnesio y calcio. Se calculó la relación Ca/Mg en dieta, plasma y orina y se evaluaron los parámetros glicémicos. Las mujeres con obesidad tenían niveles bajos de magnesio en la dieta, concentraciones reducidas de magnesio en plasma y eritrocitos, y excreción urinaria de magnesio elevada. La concentración plasmática de calcio fue menor en pacientes con obesidad, y la excreción urinaria de calcio fue mayor que en el grupo de mujeres con peso normal. La ingesta dietética de magnesio y calcio por kilogramo de peso corporal por día fue menor en las mujeres con obesidad, que en el grupo control. La relación Ca/Mg en plasma y orina estaba elevada en mujeres con obesidad. Se encontró una correlación significativa entre los biomarcadores de magnesio y los parámetros de calcio. La relación Ca / Mg parece estar asociada con la resistencia a la insulina en mujeres con obesidad.

EFFECTIVENESS OF AN EDUCATIONAL INTERVENTION TO REDUCE THE CONSUMPTION OF HIGH-CALORIE FOODS IN PUBLIC SCHOOL CHILDREN IN TERESINA, PIAUÍ (BRAZIL).

INTRODUCTION: there is high prevalence of overweight and poor food habits among adolescents, and these factors contribute to the development of chronic diseases. OBJECTIVE: the aim of this study was to evaluate the effectiveness of an educational intervention designed to reduce the consumption of high-calorie foods in public school children in Teresina, Piaui, Brazil. MATERIALS AND METHODS: quasi-experimental, randomized, quantitative intervention study involving adolescents (n = 126) of both sexes aged 10-14 years. An educational intervention, which involved 9 weekly meetings, was developed. A questionnaire was completed prior and subsequent to the intervention. Associations between variables were examined using a chi-square test (x2). RESULTS AND DISCUSSION: there was a significant reduction in the consumption of soft drinks and processed juices subsequent to the educational intervention (p = 0.007). It has further reduction in weekly consumption of food like meat and sausage (p = 0.072). Adolescents' weekly consumption of fried foods and potato chips also decreased significantly subsequent to the educational intervention (p < 0.001). CONCLUSIONS: the food and nutrition educational program was efficacious in reducing the adolescents' intake of high-calorie food and drinks and contributed to an improvement in the quality of food consumed by the schoolchildren evaluated.

Introdución: existe una alta prevalencia de sobrepeso y hábitos alimentarios pobres entre los adolescentes, y estos factores contribuyen al desarrollo de enfermedades crónicas. Objetivo: el objetivo de este estudio fue evaluar la efectividad de una intervención educativa diseñada para reducir el consumo de alimentos con alto contenido calórico en los niños de las escuelas públicas en Teresina, Piauí (Brasil). Material y métodos: estudio cuasi-experimental, aleatorizados y de intervención cuantitativo realizado con adolescentes (n = 126), con edades comprendidas entre 10 y 14 años, de ambos sexos. La intervención educativa se desarrolló durante nueve semanas, con reuniones semanales. Se realizó una encuesta previa y posterior a la intervención. Las asociaciones entre las variables fueron examinadas usando una prueba de chi-cuadrado (x2). Resultados: se observó una reducción significativa en el consumo de refrescos y jugos procesados posterior a la intervención educativa (p = 0,007). Tiene una mayor reducción en el consumo semanal de alimentos embutidos (p = 0,072). El consumo semanal de los adolescentes de alimentos fritos y patatas fritas también se redujo significativamente después de la intervención educativa (p < 0,001). Conclusiones: el programa educativo de alimentación y nutrición fue eficaz en la reducción de la ingesta de alimentos altos en calorías y bebidas de los adolescentes, lo cual contribuyó a una mejora en la calidad de los alimentos consumidos por los niños de las escuelas evaluadas.

Influence of magnesium on biochemical parameters of iron and oxidative stress in patients with type 2 diabetes.

INTRODUCTION: Studies have shown that oxidative stress, found in patients with type 2 diabetes, may be due to changes in the metabolism of minerals, such as magnesium and iron. Data related to compartmentalization of these minerals in diabetes are scarce and controversial. OBJECTIVE: This study assessed the influence of magnesium on biochemical parameters of iron and oxidative stress in patients with type 2 diabetes. METHODS: A case-control study in male and female subjects aged 27-59 years, divided into two groups: type 2 diabetes (n=40) and control (n=48). Intake of magnesium and iron was assessed by three-day food record. Plasma, erythrocyte and urinary levels of magnesium, serum iron, ferritin, total iron binding capacity, fasting glucose, glycated hemoglobin, insulin, creatinine clearance and plasma thiobarbituric acid reactive substances (TBARS) were analyzed. RESULTS AND DISCUSSION: Magnesium intake and plasma magnesium were lower in diabetic subjects. There was low urinary magnesium excretion, with no difference between groups. Although normal, the diabetic group had lower serum iron and ferritin concentrations compared to control subjects. Plasma TBARS in diabetic patients was higher than control while creatinine clearance was lower. An inverse correlation between erythrocyte magnesium and serum iron and ferritin was observed in the diabetes group. CONCLUSIONS: Diabetes induced hypomagnesemia and this, associated with chronic hyperglycemia, may have enhanced oxidative stress. Erythrocyte magnesium may have contributed to prevent iron overload and worsening of oxidative stress and hyperglycemic status.

Introducción: Los estudios han demostrado que el estrés oxidativo, que se encuentra en pacientes con diabetes tipo 2, puede ser debido a cambios en el metabolismo de los minerales, como el magnesio y el hierro. Los datos relacionados con la compartimentación de estos minerales en la diabetes son pocos y cuestionables. Objetivos: Evaluar la influencia del magnesio sobre parámetros bioquímicos de hierro y el estrés oxidativo en pacientes con diabetes tipo 2. Métodos: Estudio caso-control en los sujetos masculinos y femeninos de edad 27 a 59 años, divididos en dos grupos: la diabetes tipo 2 (n = 40) y control (n = 48). La ingesta de magnesio y hierro se evaluó por tres días registro de alimentos. Plasma, eritrocitos y los niveles urinarios de magnesio, hierro sérico, ferritina, capacidad total de fijación del hierro, glucosa en ayunas, hemoglobina glucosilada, la insulina, el aclaramiento de creatinina y el plasma se analizaron tiobarbitúrico sustancias reactivas al ácido (TBARS). Resultados y Discusión: La ingesta de magnesio y el magnesio en plasma fueron más bajos en los pacientes diabéticos. Hubo baja excreción urinaria de magnesio, sin diferencias entre los grupos. Aunque lo normal, el grupo de diabéticos tenían concentraciones de hierro y ferritina sérica inferiores en comparación con los sujetos control. TBARS plasmáticos en los pacientes diabéticos fue mayor que en el control, mientras que la depuración de creatinina fue menor. Se observó una correlación inversa entre el magnesio y el hierro en suero de los eritrocitos y la ferritina en el grupo de diabetes. Conclusiones: Diabetes hipomagnesemia inducida y esto, asociado a la hiperglucemia crónica, pueden haber mejorado el estrés oxidativo. Magnesio eritrocitaria puede haber contribuido a evitar la sobrecarga de hierro y el empeoramiento de estrés oxidativo y el estado de hiperglucemia.

Influence of cortisol on zinc metabolism in morbidly obese women.

INTRODUCTION: The accumulation of visceral fat affects the metabolism of hormones and some nutrients, but these mechanisms remain unclear. OBJECTIVE: To assess the influence of cortisol on the metabolism of zinc in morbidly obese women. METHOD: Cross-sectional, case-control study involving 80 women aged between 20 and 59 years. The participants were divided into two groups: experimental (morbidly obese, n = 40) and control (normal weight, n = 40). Zinc concentrations were determined by atomic absorption spectroscopy and serum and urinary cortisol by chemiluminescence method. RESULTS: Zinc intake was significantly different between groups. Mean plasma zinc was lower in obese compared to control group. Mean values for erythrocyte zinc were 44.52 ± 7.84 µg/gHb and 40.17 ± 6.71 µg/gHb for obese and control groups, respectively. Urinary excretion of this mineral was higher in obese compared to control subjects (p < 0.05). Mean values for plasma cortisol were 9.58 ± 4.86 µg/dL for obese and 9.89 ± 5.61 µg/dL for control groups. Mean values for urinary cortisol were 163.00 ± 100.35 µg/dL and 109.71 ± 34.88 µg/dL for obese and control groups, respectively (p > 0.05). The correlation analysis between cortisol and zinc was not significant (p > 0.05). CONCLUSIONS: Obese patients have hypozincemia and high erythrocyte zinc levels. The correlation between zinc parameters and cortisol concentration showed no influence of this hormone on zinc metabolism.

Effect of zinc supplementation on superoxide dismutase activity in patients with ulcerative rectocolitis.

INTRODUCTION: Ulcerative rectocolitis is characterized by diffuse mucosal inflammation and oxidative stress. Thus, the organism activates the antioxidant defence system in an attempt to reduce the excessive production of reactive oxygen species or neutralize them. OBJECTIVE: This study evaluated the effect of zinc supplementation on the activity of the enzyme superoxide dismutase (SOD) in patients with ulcerative rectocolitis. METHODS: The study included 24 patients, aged between 20 and 59 years and diagnosed with ulcerative rectocolitis, in the remission stage of the disease, who were divided into two groups: experimental - deficient in zinc (n=12) and control - normal or high zinc (n=12). Only the first group underwent supplement intervention, in the form of zinc gluconate (30 mg Zn/day), taken daily in the morning, fasted for 60 days. Plasma and erythrocyte zinc concentrations were determined by flame atomic absorption spectrophotometer. The erythrocyte SOD activity was determined in vitro according to the methodology recommended by the manufacturer Randox. RESULTS AND DISCUSSION: Zinc supplementation caused a significant increase in the plasma concentrations of the mineral, and showed a significant reduction in erythrocyte zinc, remaining within normal limits. The SOD activity was high in patients of both the experimental and control groups, with no difference after supplementation. CONCLUSION: This study demonstrates that zinc supplementation improves the homeostatic condition of the mineral, with no change in SOD activity, as a marker of oxidative stress in patients with ulcerative rectocolitis.

Introducción: La colitis ulcerosa se caracteriza por la inflamación difusa de la mucosa y el estrés oxidativo. De esta forma, el cuerpo activa el sistema de defensa antioxidante en un intento de reducir la producción excesiva de especies reactivas de oxígeno, así como poder neutralizarlos. Objetivo: Este estudio evaluó el efecto de la suplementación de zinc sobre la actividad de la enzima superóxido dismutasa en pacientes con colitis ulcerosa. Métodos: El estudio incluyó 24 pacientes, con edades comprendidas entre 20 y 59 años y con diagnóstico de colitis ulcerosa en fase de remisión de la enfermedad. Los pacientes fueron divididos en dos grupos: experimental - deficiencia de zinc (n = 12) y control - normales o con altos contenido de zinc (n = 12). El grupo experimental se sometió a tratamiento con suplemento de drogas, en forma de gluconato de zinc (30 mg Zn / día), administrada diariamente por la mañana en ayunas durante 60 días. Las concentraciones en plasma y los eritrocitos de zinc se determinaron por espectrofotometría de absorción atómica de llama. La actividad de la superóxido dismutasa (SOD) se determinó por el método de eritrocitos in vitro utilizando el kit de Randox. Resultados y Discusión: La suplementación de zinc causó un aumento significativo en las concentraciones plasmáticas de mineral y mostró una reducción significativa en los eritrocitos, permaneciendo dentro de los límites normales. La actividad de SOD fue mayor en los pacientes de los grupos experimentales y de control, sin diferencias después de la suplementación. Conclusión: El estudio evidenció que la administración de suplementos de zinc mejora la condición homeostática del mineral, sin ningún cambio en la actividad de SOD, como un marcador de estrés oxidativo en pacientes con colitis ulcerosa.