Serum zinc reference intervals and its relationship with dietary, functional, and biochemical indicators in 6- to 9-year-old healthy children.

BACKGROUND: Zinc is an important cause of morbidity, particularly among young children. The dietary, functional, and biochemical indicators should be used to assess zinc status and to indicate the need for zinc interventions. OBJECTIVE: The purpose of this study was to determine the zinc status and reference intervals for serum zinc concentration considering dietary, functional, and biochemical indicators in apparently healthy children in the Northeast Region of Brazil. DESIGN: The cross-sectional study included 131 healthy children: 72 girls and 59 boys, aged between 6 and 9 years. Anthropometric assessment was made by body mass index (BMI) and age; dietary assessment by prospective 3-day food register, and an evaluation of total proteins was performed. Zinc in the serum samples was analyzed in triplicate in the same assay flame, using atomic absorption spectrophotometry. RESULTS: With respect to dietary assessment, only the intake of fiber and calcium was below the recommendations by age and gender. All subjects were eutrophic according to BMI and age classification. Zinc intake correlated with energy (p=0.0019), protein (p=0.0054), fat (p<0.0001), carbohydrate (p=0.0305), fiber (p=0.0465), calcium (p=0.0006), and iron (p=0.0003) intakes. Serum zinc correlated with protein intake (p=0.0145) and serum albumin (p=0.0141), globulin (p=0.0041), and albumin/globulin ratio (p=0.0043). Biochemical parameters were all within the normal reference range. Reference intervals for basal serum zinc concentration were 0.70-1.14 µg/mL in boys, 0.73-1.17 µg/mL in girls, and 0.72-1.15 µg/mL in the total population. CONCLUSIONS: This study presents pediatric reference intervals for serum zinc concentration, considering dietary, functional, and biochemical indicators, which are useful to establish the zinc status in specific groups. In this regard, there are few studies in the literature conducted under these conditions, which make it an innovative methodology.

Nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children.

BACKGROUND: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cell-mediated immune dysfunction, and cognitive impairment. OBJECTIVE: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children. DESIGN: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n=31) and an experimental group (10 mg Zn/day, n=31) for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. RESULTS: Our study showed (1) an increased body mass index for age and an increased phase angle in the experimental group; (2) a positive correlation between nutritional assessment parameters in both groups; (3) increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4) increased consumption of all nutrients, including zinc, in the experimental group; and (5) an increased serum zinc concentration in both groups (p<0.0001). CONCLUSIONS: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Bioelectrical impedance vector analysis for evaluating zinc supplementation in prepubertal and healthy children.

BACKGROUND: The prevalence of abnormal nutritional status has increased in children and adolescents. Nutritional assessment is important for monitoring the health and nutritional status. Bioelectrical impedance vector analysis (BIVA) combines changes in tissue hydration and structure and body composition that can be assessed. OBJECTIVES: The objective of this study was to use BIVA to evaluate nutritional status in 60 prepubertal children, aged between 8 and 9 years, supplemented with zinc, to detect possible changes in body composition. DESIGN: We performed a randomized, controlled, triple-blind study. The children were divided into the control group (CG; sorbitol 10%, n=29) or the experimental group (EG; 10 mg Zn/day, n=31), and the duration of the experiment was 3 months. Anthropometric assessments were performed for all of the children. RESULTS: The body mass index-for-age increased after oral zinc supplementation in the EG (p=0.005). BIVA indicated that the CG demonstrated a tendency for dehydration and decreased soft tissue and the EG demonstrated a tendency for increased soft tissue, primarily the fat-free mass. After analyses of BIVA ellipses, we observed that this method could detect improvements in body composition in healthy children supplemented with zinc. CONCLUSIONS: These results suggest that BIVA could be an auxiliary method for studying a small population undergoing zinc intervention.

Oral zinc supplementation decreases the serum iron concentration in healthy schoolchildren: a pilot study.

The recognized antagonistic actions between zinc and iron prompted us to study this subject in children. A convenience sample was used. Thirty healthy children between 8 and 9 years of age were studied with the aim of establishing the effect of a 3-mo oral zinc supplementation on iron status. Fifteen individuals were given a placebo (control group), and 15 were given 10 mg Zn/day (experimental group). Blood samples were collected at 0, 60, 120, 180 and 210 min after a 12-h overnight fast, before and after placebo or zinc supplementation. This supplementation was associated with significant improvements in energy, protein, fat, carbohydrate, fiber, calcium, iron, and zinc intake in accordance with the recommendations for age and sex. The basal serum zinc concentration significantly increased after oral zinc supplementation (p < 0.001). However, basal serum iron concentrations and area under the iron curves significantly decreased in the experimental group (p < 0.0001) and remained at the same level throughout the 210-min study. The values obtained for hemoglobin, mean corpuscular volume, ferritin, transferrin, transferrin saturation, ceruloplasmin and total protein were within normal reference ranges. In conclusion, the decrease in serum iron was likely due to the effects of chronic zinc administration, and the decrease in serum iron was not sufficient to cause anemia.

Kinetics of zinc status and zinc deficiency in Berardinelli-Seip syndrome.

Berardinelli-Seip syndrome (BSS) is a very rare disorder characterized by near-complete absence of adipose tissue from birth or early infancy, hypoleptinemia, hypertriglyceridemia, insulin resistance, diabetes mellitus, and other clinical signals. It is caused by mutations in AGPAT2 or Gng3lg. We evaluated 10 BSS patients and 10 healthy subjects. A single dose of 382.43 µmol zinc was administered intravenously before and after 3 months of oral zinc supplementation. Blood samples were collected from the contralateral arm at 0, 30, 60, 90, and 120 min after zinc injection. Plasma and serum were obtained to measure hematological and biochemical parameters. Urine was collected to measure creatinine, protein, and zinc. Basal serum zinc levels were similar in controls and BSS patients. However, serum zinc profiles were significant reduced in BSS patients in comparison with controls. The change in total-body zinc clearance was more significant in BSS patients, indicating that these patients had suboptimum zinc deficiency.

Positive effects of zinc supplementation on growth, GH, IGF1, and IGFBP3 in eutrophic children.

Zinc is an essential micronutrient for growth and development. Its deficiency causes growth retardation in children and adolescents. The present study analyzes the effect of zinc on growth hormone (GH) secretion, insulin-like growth factor 1 (IGF1), and insulin-like growth factor-binding protein 3 (IGFBP3) in normal children before puberty. Thirty normal children were studied, 15 boys and 15 girls, aged 6-9 years. They were orally supplemented with 5 mg Zn/day for 3 months and 0.06537 mg Zn/kg body weight was injected before and after oral supplementation. Dietary intake and anthropometric measurements were assessed at baseline and end of study. Plasma GH levels increased during intravenous zinc administration and IGF1 and IGFBP3 increased after oral zinc supplementation. There was a positive correlation between the areas under the curves of GH and zinc after oral supplementation. Zinc supplementation was possibly effective in improving the body zinc status of the children, secretory levels of IGF1 and IGFBP3, GH potentialization, and height.

Sensitivity of zinc kinetics and nutritional assessment of children submitted to venous zinc tolerance test.

OBJECTIVE: The purposes of this study were to investigate the kinetics of zinc in schoolchildren between the ages of 6 and 9 years, of both sexes, and to verify its sensitivity in detecting alterations in body zinc status. METHODS: Nutritional assessment was performed by body mass index. Food intake, venous zinc tolerance test, and zinc kinetics were carried out before and after 3-month oral zinc supplementation. RESULTS: Of the 42 children studied, 76.2% had healthy weight. Only energy, calcium, and fiber intake were suboptimal before and after oral zinc supplementation. Serum zinc and total-body zinc clearance, although at normal levels, increased significantly after zinc supplementation. CONCLUSION: We concluded, therefore, that kinetics is a sensitive tool for detecting changes in body zinc status, even in children without a deficiency of this mineral. Furthermore, kinetics showed a positive response to supplementation and may be a sensitive parameter for evaluating the efficacy of this therapy.

[Relation of adult mortality and socioeconomical data on metropolitan regions of Brazil]. / Relação entre mortalidade adulta e indicadores socioeconômicos nas Regiões Metropolitanas do Brasil.

PURPOSE: To evaluate the association between the adult mortality, in the age range between 10 and 64 years old in 2000, and socioeconomic indicators for 16 metropolitan regions of Brazil. METHODS: From the datas of the Mortality System from the Ministry of Heath, were calculated the crude mortality rates (CMR) to all the causes of dead and sex, for the 16 metropolitan regions in Brazil. As a form of guarantee the spacial camparability, the CMR were standardized by age and sex, achieving the total mortality-standardized rates and for sex by the direct method of standardization. The correlation of Pearson was obtained for the 9 indicators and the analysis of cluster was used for the agroupment of the metropolitan regions. RESULTS: The matrix of correlation of Pearson showed significant correlation only between the TMSR, the urbanization degree and residence with rubbish collection. Three groups of metropolitan regions were identified. CONCLUSION: The analysis of agroupment identified three groups: 1--Porto Alegre, São Paulo, Vitória, Curitiba, Maceió, Rio de Janeiro e recife; 2--Florianópolis, Natal, Fortaleza, Brasília e São Luís e 3--Goiânia, Belo Horizonte, Salvador e Belém, that showed be significantly different by analysis of variance (P = 0.000).