Interaction between blood selenium concentration and a levels of oxidative stress and antioxidative capacity in healthy children

Review on the health-promoting effect of adequate selenium status

Selenium is an essential microelement involved in various biological processes. Selenium deficiency increases the risk of human immunodeficiency virus infection, cancer, cardiovascular disease, and inflammatory bowel disease. Selenium possesses anti-oxidant, anti-cancer, immunomodulatory, hypoglycemic, and intestinal microbiota-regulating properties. The non-linear dose-response relationship between selenium status and health effects is U-shaped; individuals with low baseline selenium levels may benefit from supplementation, whereas those with acceptable or high selenium levels may face possible health hazards. Selenium supplementation is beneficial in various populations and conditions; however, given its small safety window, the safety of selenium supplementation is still a subject of debate. This review summarizes the current understanding of the health-promoting effects of selenium on the human body, the dietary reference intake, and evidence of the association between selenium deficiency and disease.

Low urinary selenium levels are associated with iodine deficiency in Brazilian schoolchildren and adolescents

BACKGROUND

Selenium (Se) and iodine (Io) are important micronutrients for the proper functioning of the thyroid gland, as they are crucial for the synthesis and activation of the thyroid hormones (TH) triiodothyronine (T₃) and thyroxine (T₄).

OBJECTIVE

To evaluate the Se and Io nutritional status among schoolchildren.

METHODOLOGY

Cross-sectional, descriptive and analytical study conducted in 982 schoolchildren aged 6-14 years from public schools in the state of Bahia, Brazil. Sociodemographic and anthropometric variables, as well as urinary Se (USC) and Io concentrations (UIC) using the inductively coupled plasma mass spectrometry (ICP-MS) method and thyroid-stimulating hormone (TSH) from filter paper blood collection, were evaluated.

RESULTS

The median USC and UIC were 38.7 and 210.0 (IQR: 26.8-52.9 and 129.3-334.1 μg/L, respectively). The prevalence of iodine deficiency and excessive UIC were observed in 17.1% and 30.9% of schoolchildren, respectively. Concomitant low USC and IoD was found in 3.9% of schoolchildren. There was a positive correlation between USC and UIC (r = 0.60; p = 0.00). The median TSH was 0.95 (IQR: 0.69-1.30 µUI/L).

CONCLUSIONS

This study demonstrates that USC is a good biomarker for assessing Se status, meantime more studies are needed to establish cutoff USC in child population. Despite adequate median intake, a subgroup of schoolchildren had IoD and low USC. The correlation between UIC and USC point at the importance of two micronutrients, raising the question whether measuring Se should be included in monitoring programs that address the prevention of nutritional disturbances.

The Total Antioxidant Status, Serum Selenium Concentrations and the Ultrasound Assessment Carotid Intima Media Thickness in Patients with Arterial Hypertension

The objective of the study was to establish the correlation between serum selenium concentrations, total antioxidant status, and the carotid intima media thickness in ultrasound assessment in patients with arterial hypertension. A group of 76 people suffering from arterial hypertension was qualified to participate in the study. The mean age of the respondents was 53.48 ± 12.78. Serum selenium concentrations (Se-S) and total antioxidant status (TAS) were determined in all respondents. Se-S were determined by hydride generation atomic absorption spectroscopy (HGAAS). The antioxidant status was assessed by the enzyme-linked immunosorbent assay (ELISA). In addition, an ultrasound exam of the carotid arteries was performed, and the intima media thickness (cIMT) was measured. In the study group, Se-S and TAS were 89.73 ± 18.99 µg/L and 1.18 ± 0.35 mM. However, the cIMT measured using ultrasound was 0.68 ± 0.15 mm. cIMT was significantly greater in patients with arterial hypertension with Se-S < median in comparison to patients with arterial hypertension with Se-S ≥ median (0.73 ± 0.19 mm vs. 0.65 ± 0.10 mm, p < 0.05), as well as in patients with arterial hypertension with TAS < median than in patients with arterial hypertension with TAS ≥ median (0.79 ± 0.18 mm vs. 0.56 ± 0.13 mm, p < 0.05). In regression analysis, older age, higher BMI, smoking, and lower serum selenium concentrations were independently correlated with the greater cIMT. Higher BMI and smoking were independent risk factors for the lower TAS, and the use of ACE inhibitors, β-blockers, and higher Se-S were independent factors of protection against the lower TAS. In patients with arterial hypertension, the lower total antioxidant status due to lower serum selenium concentrations may be correlated with an increase of the carotid intima media thickness measured using ultrasound.

Assessment of antioxidant enzymes, total sialic acid, lipid bound sialic acid, vitamins and selected amino acids in children with phenylketonuria

BACKGROUND

In this study, children with phenylketonuria and healthy control subjects were assessed for glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) activity, malondialdehyde (MDA), glutathione (GSH), retinol, cholecalciferol, α-tocopherol, phylloquinone, total sialic acid (TSA), lipid bound sialic acid (LSA), total antioxidant (TAS), total oxidation (TOS), and amino acid levels, and the relationships of these variables with phenylketonuria were evaluated.

METHODS

The study included 60 children with phenylketonuria and 30 control subjects. Children with phenylketonuria were divided into hyperphenylalaninemia (HPA) and amino acid mixture (AAM) groups.

RESULTS

The HPA group had significantly lower levels of GSH-Px, CAT, GSH, TAS, α-aminobutyric acid, and taurine levels (p < 0.01, p < 0.05, p < 0.05, p < 0.001, p < 0.01, p < 0.05, respectively) than the control group. Additionally, the AAM group had significantly lower levels of CAT, TAS, and phylloquinones (p < 0.05, p < 0.05, p < 0.05, respectively) than the control group. It was observed in our study that in the HPA group, a significantly strong positive linear correlation was observed between phenylalanine and α-aminoadipic acid (r = 0.777; p = 0.002).

CONCLUSIONS

It was concluded that the levels of α-aminoadipic acid and phylloquinone might be an appropriate choice for the determination of phenylketonuria in parallel with the levels of phenylalanine. α-aminobutyric acid and phylloquinone as a supplement can decrease HPA damage.

Blood Selenium Concentration and Blood Cystatin C Concentration in a Randomly Selected Population of Healthy Children Environmentally Exposed to Lead and Cadmium

This study aimed at evaluation of a relationship between blood selenium concentration (Se-B) and blood cystatin C concentration (CST) in a randomly selected population of healthy children, environmentally exposed to lead and cadmium. The studies were conducted on 172 randomly selected children (7.98 ± 0.97 years). Among participants, the subgroups were distinguished, manifesting marginally low blood selenium concentration (Se-B 40-59 μg/l), suboptimal blood selenium concentration (Se-B: 60-79 μg/l) or optimal blood selenium concentration (Se-B ≥ 80 μg/l). At the subsequent stage, analogous subgroups of participants were selected separately in groups of children with BMI below median value (BMI <16.48 kg/m²) and in children with BMI ≥ median value (BMI ≥16.48 kg/m²). In all participants, values of Se-B and CST were estimated. In the entire group of examined children no significant differences in mean CST values were detected between groups distinguished on the base of normative Se-B values. Among children with BMI below 16.48 kg/m², children with marginally low Se-B manifested significantly higher mean CST values, as compared to children with optimum Se-B (0.95 ± 0.07 vs. 0.82 ± 0.15 mg/l, p < 0.05). In summary, in a randomly selected population of healthy children no relationships could be detected between blood selenium concentration and blood cystatin C concentration. On the other hand, in children with low body mass index, a negative non-linear relationship was present between blood selenium concentration and blood cystatin C concentration.

Increased oxidative stress parameters in children with moderate iodine deficiency

BACKGROUND

Iodine is a part of thyroid hormones and has been reported to act directly as an antioxidant or induce indirectly antioxidant enzymes. This study aimed to assess the urinary iodine concentration and its relationship between the antioxidant and oxidative stress capacity in healthy school-aged children.

METHODS

In total, 196 students from five primary schools, randomly selected between 9 and 12 years (mean age: 10.2±1.2 years), were enrolled in the study. Urinary iodine levels were measured by spectrophotometry with the Sandell-Kolthoff reaction. Total antioxidant status (TAS) and total oxidant status (TOS) were analysed from urine samples. The ratio of TOS to TAS was regarded as an oxidative stress index (OSI), an indicator of the degree of oxidative status.

RESULTS

Fifty-four percentage (107) of the children had iodine deficiency (ID) and the majority of them (30%) had mild ID. There was no severe-ID child in the population (<20 μg/L). Urine TAS levels were significantly lower in the moderate-ID group than in the mild-ID group (6.5±4.1 vs. 11.3±4.1 mmol, p<0.001) and the iodine-sufficient group (11.0±5.3 μmol, p<0.001). TOS levels and OSI were found higher in the moderate-ID group than in the mild-ID group (4.8±2.1 vs. 3.7±2.1 μmol, p<0.001) and the iodine-sufficient group (4.8±2.1 vs. 3.4±2.5 mmol, p<0.001). In the moderate-ID group, low urine iodine levels exhibited significant negative correlations with OSI (r=-0.660) and TOS (r=-0.248) and a positive correlation with TAS (r=0.475).

CONCLUSIONS

We found that children with moderate ID were exposed to more oxidative burden than children with mild ID or iodine sufficiency. Increased systemic oxidative stress induced by moderate ID could cause development of ID-related complications and diseases. Iodine supplementation could have a beneficial role in the prevention of oxidative stress.

Chrysobalanus icaco L. fruits inhibit NADPH oxidase complex and protect DNA against doxorubicin-induced damage in Wistar male rats

Chrysobalanus icaco L. is an underexplored plant found in tropical areas around the globe. Currently, there is no apparent information regarding the effects C. icaco fruits may exert in vivo or potential role in health promotion. This study aimed at providing evidence regarding the in vivo influence of this fruit on antigenotoxicity, antimutagenicity, and oxidative stress in rats. Male Wistar rats were treated with 100, 200, or 400 mg/kg body weight (bw)/d C. icaco fruit for 14 d. Doxorubicin (DXR, 15 mg/kg bw, ip) was used for DNA damaging and as an oxidant to generate reactive oxygen species (ROS). Genomic instability was assessed by the comet assay and micronucleus (MN) test, while antioxidant activity was determined by oxidative burst of neutrophils. Chrysobalanus icaco fruit polyphenols were quantified and characterized by high-performance liquid chromatography coupled to a diode array detector and tandem mass spectrometer (HPLC-DAD-MS/MS). The concentrations of 19 chemical elements were determined by inductively coupled plasma-mass spectroscopy (ICP-MS). Significant amounts of polyphenols, magnesium, and selenium were found in C. icaco fruit. This fruit displayed in vivo antioxidant activity against DXR-induced damage in rat peripheral blood neutrophils, antigenotoxicity in peripheral blood cells, and antimutagenicity in bone-marrow cells and peripheral blood cells. Correlation analyses between endpoints examined indicated that the mechanism underlying chemopreventive actions of C. icaco fruit was attributed to inhibition of NADPH oxidase complex manifested as low levels of DNA damage in animals exposed to DXR. Data indicate that phytochemicals and minerals in C. icaco fruit protect DNA against damage in vivo associated with their antioxidant properties.

Evaluation of trace element and mineral status and related to levels of amino acid in children with phenylketonuria

The aim of the present study was to examine trace elements (Zn, Cu, Mn, Se, Fe, Co, Cr, Ni, Cd, Pb), minerals (Ca, Mg, K), amino acids status in children with phenylketonuria and also whether they were correlated with each other in phenylketonuric patients. It has been found out that the HPA group was significantly lower than the control group with regards to Zn, Se, K, Ca, Mg and Zn/Cr levels (p<0.001, p<0.01, p<0.001, p<0.01, p<0.01 and p<0.001 respectively). In the patients with HPA, significantly strong positive correlations were observed between magnesium and calcium (r=0.791; p=0.001), also, indicates negative significant correlation between the concentrations of magnesium and phenylalanine (r=-0.591; p=0.026). The results of this study showed that, in the HPA group, phenylalanine-Mg relationship found, the presence of disease will in the evaluation of phenylalanine and other amino acids, together with the value of magnesium is required to consider.