Poor zinc status is associated with increased risk of insulin resistance in Spanish children

Dietary Inflammatory Potential in Pediatric Diseases: A Narrative Review

Inflammatory status is one of the main drivers in the development of non-communicable diseases (NCDs). Specific unhealthy dietary patterns and the growing consumption of ultra-processed foods (UPFs) may influence the inflammation process, which negatively modulates the gut microbiota and increases the risk of NCDs. Moreover, several chronic health conditions require special long-term dietary treatment, characterized by altered ratios of the intake of nutrients or by the consumption of disease-specific foods. In this narrative review, we aimed to collect the latest evidence on the pro-inflammatory potential of dietary patterns, foods, and nutrients in children affected by multifactorial diseases but also on the dietetic approaches used as treatment for specific diseases. Considering multifactorial diet-related diseases, the triggering effect of pro-inflammatory diets has been addressed for metabolic syndrome and inflammatory bowel diseases, and the latter for adults only. Future research is required on multiple sclerosis, type 1 diabetes, and pediatric cancer, in which the role of inflammation is emerging. For diseases requiring special diets, the role of single or multiple foods, possibly associated with inflammation, was assessed, but more studies are needed. The evidence collected highlighted the need for health professionals to consider the entire dietary pattern, providing balanced and healthy diets not only to permit the metabolic control of the disease itself, but also to prevent the development of NCDs in adolescence and adulthood. Personalized nutritional approaches, in close collaboration between the hospital, country, and families, must always be promoted together with the development of new methods for the assessment of pro-inflammatory dietary habits in pediatric age and the implementation of telemedicine.

Association of Healthy Eating Index-2015 and Dietary Approaches to Stop Hypertension Patterns with Insulin Resistance in Schoolchildren

Background: Diet quality patterns are associated with a lower incidence of insulin resistance (IR) in adults. The aim of this study was to investigate the association between two diet quality indices and IR in schoolchildren and to identify the best diet quality index associated with a lower risk of IR. Methods: A total of 854 schoolchildren (8−13 years) were included in a cross-sectional study, who completed a three-day dietary record to assess their diet. Fasting plasma glucose and insulin were also measured, and anthropometric data were collected. Healthy Eating Index-2015 (HEI-2015), Dietary Approaches to Stop Hypertension (DASH), and adjusted DASH (aDASH) were calculated as diet quality indices. The homeostasis model assessment of insulin resistance (HOMA-IR) was used, and IR was defined as HOMA-IR > 3.16. Results: The prevalence of IR was 5.5%, and it was higher in girls. The mean HEI-2015 and DASH scores were 59.3 and 23.4, respectively, and boys scored lower in both indices. In girls, having a HEI-2015 score above the 33rd percentile was associated with a lower risk of IR (odds ratio [95% CI]: 0.43 [0.19−0.96], p = 0.020). Conclusion: Greater adherence to a healthy dietary pattern, as assessed by a higher HEI-2015 score, was associated with a lower risk of IR in schoolchildren, especially in girls.

Leukocytes and Neutrophil–Lymphocyte Ratio as Indicators of Insulin Resistance in Overweight/Obese School-Children

Background and Aims

Inflammation in overweight/obesity may condition the development of insulin resistance (IR). New markers of inflammation and systemic inflammation, such as leukocyte and platelet counts, the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR), could be used as indicators of IR. The aim of the present study was to investigate the relationship between these markers and IR in overweight/obese children.

Materials and Methods

A total of 1,035 schoolchildren were studied (398 overweight/obese). Anthropometric, hematological and biochemical measurements were collected. Inflammation was considered to be present when the values of leukocytes, platelets, NLR, PLR and MLR were ≥p75 for each sex. IR was defined as HOMA-IR >3.16.

Results

In overweight/obese schoolchildren, leukocytes were higher in both boys and girls, and platelets and NLR were higher in boys with IR than in boys with insulin sensitivity. An association between leucocytes and NLR values (≥p75) and IR was found in the entire population [2.911 (1.328–6.381); p = 0.008 and 2.660 (1.185–5.968); p = 0.018, respectively] and in boys [9.255 (1.896–45.168); p = 0.006 and 6.996 (1.377–35.544); p = 0.019, respectively].

Conclusion

Elevated white blood cell values and elevated NLR in overweight/obese children, and particularly in boys, could be indicators of the presence of IR in these subjects and should be considered when predicting possible complications, such as type II diabetes mellitus.

Plasma levels of trace element status in early pregnancy and the risk of gestational diabetes mellitus: A nested case-control study

PURPOSE

We investigated the impacts of plasma levels of magnesium (Mg), zinc (Zn), calcium (Ca), iron (Fe), copper (Cu), selenium (Se), and chromium (Cr) on GDM risk and the potential mediation effect of blood glucose levels on the relationship between trace elements and GDM risk.

METHODS

This nested case-control study was based on data from a birth cohort study conducted in Wuhan, China in 2013-2016. A total of 305 GDM cases and 305 individually-matched controls were included in the study. Conditional logistic regression models were used to estimate the associations between plasma trace element concentrations and GDM risk. A mediation analysis was conducted to explore whether blood glucose levels act as a mediator between trace element levels and GDM risk.

RESULTS

An IQR increment in plasma levels of Fe and Cu was associated with a significant increase in GDM risk [OR = 2.04 (95 % CI 1.62, 2.57) and OR = 1.52 (95 % CI 1.25, 1.82)], respectively. On the other hand, an IQR increment in plasma levels of Zn and Ca was associated with a significant decrease in GDM risk [OR = 0.55 (95 % CI 0.43, 0.71) and OR = 0.72 (95 % CI 0.56, 0.92)], respectively. The mediation analysis showed significant mediation of the association between Cu and GDM risk via the FBG (%mediated: 19.27 %), 1 h-PBG (12.64 %), 2h-PBG (28.44 %) pathways.

CONCLUSIONS

Plasma levels of Zn and Ca were negatively associated with GDM risk, while Fe and Cu were positively associated. Blood glucose levels act as a mediator between plasma trace element exposures and GDM risk.

Association between serum zinc concentrations and metabolic risk factors among Chinese children and adolescents

The aim of the present study was to examine whether serum Zn concentrations were associated with metabolic risk factors in Chinese children and adolescents. This was a cross-sectional study including 3241 participants, aged 6 to 17 years, from Jiangsu, China. Metabolic risk factors included fasting glucose (FG), total cholesterol (TC), TAG, HDL-cholesterol, LDL-cholesterol, systolic blood pressure and diastolic blood pressure. Data were analysed using multi-variable linear regression and generalised additive models, which were adjusted for age, sex, high-sensitive C-reactive protein, estimated glomerular filtration rate, BMI and region of residence, to assess the associations of serum Zn concentrations with metabolic risk factors. We observed a negative association between serum Zn concentrations and FG (coefficient = -0·532; 95 % CI -0·569, -0·495; P < 0·001). Moreover, TC (coefficient = 0·175; 95 % CI 0·127, 0·222; P < 0·001), HDL-cholesterol (coefficient = 0·137; 95 % CI 0·082, 0·193; P < 0·001) and LDL-cholesterol (coefficient = 0·195; 95 % CI 0·128, 0·263; P < 0·001) were found to be positively associated with Zn levels. A generalised additive model showed that the negative association between serum Zn and FG was weak at lower serum Zn concentrations and was stronger with the increase in serum Zn concentrations. Additionally, a U-shaped association between serum Zn and TAG was observed. Serum Zn concentrations were associated with FG, TC, TAG, HDL-cholesterol and LDL-cholesterol levels in Chinese children and adolescents. Lower levels of serum Zn were more likely related to a poor metabolic status.

The effect of zinc deficiency and iron overload on endocrine and exocrine pancreatic function in children with transfusion-dependent thalassemia: a cross-sectional study

BACKGROUND

Children with transfusion-dependent thalassemia (TDT) suffer from secondary hemosiderosis and the delirious effects this iron overload has on their different body organs, including the pancreas. They are also more prone to develop zinc deficiency than the general pediatric population. This study aimed to determine the effect of zinc deficiency and iron overload on the endocrine and exocrine pancreas in TDT children.

METHODS

Eighty children, already diagnosed with TDT, were included in this study. We assessed the following in the participant children: serum ferritin, serum zinc, endocrine pancreatic function (oral glucose tolerance test (OGTT), fasting insulin level and from them, HOMA-IR was calculated), and exocrine pancreatic function (serum lipase and serum amylase).

RESULTS

Forty-four TDT children had a subnormal zinc level, while 36 of them had a normal serum zinc level. TDT children with low serum zinc had significantly more impaired endocrine pancreatic function and an abnormally high serum lipase than children with normal serum zinc, p < 0.05 in all. Serum zinc was significantly lower in TDT children with serum ferritin above the ferritin threshold (≥2500 ng/ml) than those below (59.1 ± 20.2 vs. 77.5 ± 28.13), p = 0.02. TDT children, having a serum ferritin ≥2500 ng/ml, had significantly more frequently impaired endocrine pancreatic function and abnormally high serum lipase than TDT children below the ferritin threshold, p < 0.05 in all.

CONCLUSION

In children with transfusion-dependent thalassemia, zinc deficiency aggravates iron-induced pancreatic exocrine and endocrine dysfunction.

[Evaluating malnutrition in pediatrics, a current challenge]

Malnutrition in pediatric patients conditions their health/illness. Malnutrition in sick children further aggravates their baseline situation, and conditions their evolution and prognosis. Despite its relevance, it is not evaluated in many cases, nor is there a single definition that facilitates its diagnosis. The objective of this article is to establish the principal aspects to consider when evaluating malnutrition, and to highlight the importance of routine evaluation.

[Zinc and its relation to insulin resistance in children]

Zinc is an essential trace element involved in catalytic, structural, and regulatory functions, participating also in the metabolism of nutrients. Its role in insulin resistance appears to be of great importance, as it is involved in oxidative stress, the endocrine regulation of insulin, and the regulation of glucose uptake. For this reason, both intake and serum levels of zinc are inversely related to insulin resistance. Currently, zinc intake in children is low, and zinc deficiency exists in a significant proportion. Zinc can be found in meat, fish, eggs, and dairy products. Although it certainly is present in foods of plant origin, their high phytate contents generally reduce its bioavailability. For this reason, it is important to monitor intake throughout childhood, and to consider supplementation in children with insulin resistance or obesity.

Zinc Nutritional Status in a Series of Children with Chronic Diseases: A Cross-Sectional Study

BACKGROUND

Zinc is an essential trace element for the normal growth and development of human beings. The main objective was to evaluate the nutritional status of zinc and its association with nutritional indicators in a series of children with chronic diseases.

METHODS

The prevalence of patients with dietary zinc deficiency or deficit zinc intake (<80% DRI: dietary reference intake) was analyzed through prospective 72 h dietary surveys, and serum zinc deficiency or hypozincemia (≤70 µg/dL in children under 10 years of age in both sexes and in females older than 10 years and <74 μg/dL in males older than 10 years) was measured through atomic absorption spectrophotometry. The participants were classified according to their nutritional status by body mass index (BMI).

RESULTS

Mean serum zinc level in obese (87 µg/dL), undernourished (85 µg/dL), and eutrophic children (88 µg/dL) were normal, but in the undernutrition (60% DRI) and eutrophic (67% DRI) groups the mean dietary zinc intake was low compared to that in the obesity group (81% DRI). There were different associations between nutritional parameters, dietary zinc intake, and serum zinc. All patients with hypozincemia had dietary zinc deficiency.

CONCLUSIONS

In the whole series, 69% of participants showed a zinc intake lower than recommended and might be at high risk of zinc deficiency.

Physical activity practice and sports preferences in a group of Spanish schoolchildren depending on sex and parental care: a gender perspective

BACKGROUND

Physical activity plays an important role in the maintenance of health, and it is especially important during childhood. However, the lack of information about differences in physical activity practice and sports preferences of children considering gender differences can result in non-effective policies that enhance inequalities between sexes. The aim of this study is to identify the sports preferences of Spanish schoolchildren and their physical activity practice behaviors depending on their sex and their parental care, analyzing the possible differences from a gender perspective.

METHOD

Three hundred sixty-four Spanish schoolchildren (179 girls, 185 boys) participated in this cross-sectional study. A daily physical activity questionnaire was used to evaluate physical activity level (PAL), moderate-to-vigorous physical activity (MVPA) and sports preferences and a socio-health questionnaire were used to collect data about parental care. Statistical analysis was performed using SPSS and applying Student's T-test for normal variables, Mann-Whitney U-test for non-parametrical variables, and chi-square (χ2) test for categorical variables. Subsequently, odds ratios were used to analyze associations between the physical activity practice of the children and parental care.

RESULTS

PAL and time spent in MVPA was significantly lower for girls compared to boys (1.44 ± 0.07 vs. 1.46 ± 0.07, p < 0.001 and 0.74 ± 0.40 h/day vs. 0.90 ± 0.45 h/day; p < 0.001, respectively). Dancing, rhythmic gymnastics, skating, and water sports were practiced more by girls, while football, wrestling sports, handball, and racket sports were practiced more by boys (p < 0.05). Children cared for by their fathers had higher odds for physical activity practice (OR = 1.995 (1.202-3.310), p = 0.008).

CONCLUSION

Physical activity among girls was less frequent and less intense. Girls opted for individual sports with artistic connotations, while boys often practiced more team contact sports. Furthermore, children are more physically actives when their father is in charge of them.

[Weight status, body composition, and diet quality of Spanish schoolchildren according to their level of adherence to the 24-hour movement guidelines]

Introduction

Introduction: moderate to vigorous physical activity, limiting sedentary behaviors, and getting adequate rest are lifestyle factors that help prevent overweight and obesity. However, there are few studies that relate all of these factors to weight status, body composition, and diet quality in school children. Objective: to assess the differences in anthropometric status and diet quality in a group of Spanish schoolchildren, according to their level of adherence to the 24-hour movement guidelines. Methods: a total of 367 schoolchildren aged 7-11 years were studied. Anthropometric, dietary, and movement patterns were collected. Subsequently, they were divided into three groups based on their adherence to the extant guidelines: low adherence (BA), medium adherence (AM) and high adherence (AA). Results: only 15 % of the schoolchildren met the guidelines. The percentage of overweight was higher in the BA group than in the AM and AA groups. The BA group also had a lower fibre intake; a lower contribution to the recommendations for vitamins B6, B12 and C, selenium and magnesium; and a higher intake of saturated fatty acids. The schoolchildren who did not meet screen time recommendations had a higher odds ratio for overweight/obesity (OR = 1.92 (1.10-3.36); p = 0.022). Conclusion: schoolchildren who adhere to 2 or more movement guideline recommendations had less overweight and a diet of better nutritional quality. Non-compliance with the screen time recommendation leads to a higher risk of overweight or obesity.

Type 2 Diabetes-Associated Genetic Polymorphisms as Potential Disease Predictors

Diabetes is a major cause of mortality worldwide. There are several types of diabetes, with type 2 diabetes mellitus (T2DM) being the most common. Many factors, including environmental and genetic factors, are involved in the etiology of the disease. Numerous studies have reported the role of genetic polymorphisms in the initiation and development of T2DM. While genome-wide association studies have identified around more than 200 susceptibility loci, it remains unclear whether these loci are correlated with the pathophysiology of the disease. The present review aimed to elucidate the potential genetic mechanisms underlying T2DM. We found that some genetic polymorphisms were related to T2DM, either in the form of single-nucleotide polymorphisms or direct amino acid changes in proteins. These polymorphisms are potential predictors for the management of T2DM.

Physical activity and sedentary behavior impacts on dietary water intake and hydration status in Spanish schoolchildren: A cross-sectional study

BACKGROUND

The importance of maintaining an adequate hydration status and the complexity of the water balance make it necessary to study the lifestyle factors that can influence or modify these variables. The aim of this study was to evaluate the hydration status and dietary water intake for a sample of Spanish schoolchildren from 7 to 12 years old and their associations with physical activity (PA) and sedentary behaviors.

METHODS

A total of 242 schoolchildren was studied (49.17% females). A 24-hour urine sample was collected from each child, and the urine volume and osmolality were measured to estimate the hydration status (adequate hydration ≤800 mOsm/kg). In addition, a 3-day dietary record was completed to evaluate their water intake according to EFSA parameters. Dietary information was processed with DIAL software, and a statistical analysis was performed using SPSS. Student's t-test was used to study the normal variables, and the Mann-Whitney U test was used for those that were not normal. In the case of the categorical variables, the Z and Chi-Square proportions tests were used. The Bonferroni test was used to adjust the values in multiple comparisons. To evaluate the influence of these lifestyles on the urine osmolality, a 2-way ANOVA and an odds ratio were used.

RESULTS

A total of 48.3% of the sample presented an adequate hydration status, and the percentage was significantly higher in females (p = 0.003). Only 20.9% showed an adequate intake of dietary water. The lifestyle influence reveals that more inactive and non-sedentary schoolchildren were adequately hydrated (p = 0.008). PA (practice ≥1 h/day) was associated with a higher risk of having an inadequate hydration status, even when accounting for sex and other lifestyle factors (OR = 1.753(1.006-3.054), p = 0.048).

CONCLUSIONS

Approximately half of the participants presented an inadequate hydration status (which was higher in males than in females). PA (practice ≥1 h/day) was associated with a higher risk of inadequate hydration. This fact highlighted the importance of raising awareness about hydration in children, especially in ones who are more active.

[Association between serum zinc level and hypercholesterolemia and insulin resistance in Brazilian children]

The objective of the study was to assess the association between serum zinc level and cardiometabolic factors in prepubertal Brazilian children. This was a cross-sectional study in a representative sample of schoolchildren 8 to 9 years of age in public and private urban schools in Viçosa, Minas Gerais State, Brazil. Body composition was assessed with dual-energy x-ray absorptiometry. The study measured serum glucose, insulin, total cholesterol, high and low density lipoprotein cholesterol, triglycerides, apolipoproteins A (Apo A) and B, uric acid, leptin, homocysteine, ultrasenstive C-reactive protein, and serum zinc. Arterial pressure was measured with automatic inflation equipment. Zinc deficiency was observed in 1.3% of the children. Girls showed the worst cardiometabolic profile, with higher prevalence of increased android fat, triglycerides, insulin resistance, leptin, zinc, and Apo A. In the first tertile of serum zinc concentration, prevalence of insulin resistance was 96% higher (PR = 1.96; 95%CI: 1.04-3.66) and hypercholesterolemia was 23% lower (PR = 0.77; 95%CI: 0.61-0.96) than in the reference category (grouped 2nd and 3rd tertiles of serum zinc concentration). Despite the low prevalence of zinc deficiency, insulin resistance was more prevalent in children in the lowest third of serum zinc concentration. It is important to prevent cardiometabolic alterations in childhood, especially insulin resistance, with an emphasis on serum zinc level.

Assessment of Zinc Status in School-Age Children from Rural Areas in China Nutrition and Health Survey 2002 and 2012

Zinc is an essential trace element for growth and development in children, but zinc deficiency is a serious nutritional problem worldwide. Our study aimed to assess the zinc status of school-age children living in rural areas of China and to examine the change of zinc status based on the China Nutrition and Health Survey 2002 and 2012. We used the probability proportional to size sampling method for subject selection, and a total of 3407 school-age children were included in this study. Zinc status was assessed by three items of indicators recommended by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), the International Atomic Energy Agency (IAEA), and the International Zinc Nutrition Consultative Group (IZiNCG). The concentration of serum zinc was 718.2 μg/L, and 44.4% of children being zinc deficiency in 2002, while 846.8 μg/L and 10.4% in 2012. Zinc intake was 7.8 mg/day with a 7.6% inadequate zinc intake in 2002, together with 6.9 mg/day and 38.2% in 2012. Height-for-age Z score was -1.06 and 19.1% of children being stunting in 2002, as well as -0.15 and 6.8% in 2012. In conclusion, the zinc status of school-age children living in rural areas of China has been significantly improved in addition to zinc intake over the past 10 years. However, the zinc deficiency still observed in poor rural areas of China in 2012. In addition, we suggested that the zinc bioavailability should be taken into account when assessing zinc status in population.

β-Carotene Concentration and Its Association with Inflammatory Biomarkers in Spanish Schoolchildren

AIM

To examine the correlation between inflammatory biomarkers and plasma β-carotene levels in children.

METHODS

A total of 564 Spanish schoolchildren aged 9-12 were observed and studied. Plasma β-carotene levels were assessed by HPLC. A β-carotene level <4.83 µg/dL (0.09 µmol/L) was considered deficient. Plasma tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured by immunoenzyme assays. Serum high-sensitivity C-reactive protein (hs-CRP) was tested by immunonephelometry.

RESULTS

Subjects who were β-carotene-deficient (23.1% of the studied children) had higher IL-6 levels than subjects with normal β-carotene concentrations. The log-IL-6 and log-hs-CRP concentrations, but not the log-TNF-α level, were strongly and inversely related to the plasma log-β-carotene level (taking into account log-age, energy intake, log-triglycerides, gender, log-body mass index, log-β-carotene intake, energy from lipids and cholesterol as covariables). When the 3 inflammatory biomarkers were introduced into the regression model along with the corresponding covariables, only the log-IL-6 level was related to the plasma log-β-carotene level (β = -0.505 ± 0.078; p < 0.001).

CONCLUSIONS

Inflammatory status, in particular IL-6 levels, appears to be negatively associated with plasma β-carotene levels in schoolchildren.

Zinc Supplementation Does Not Alter Indicators of Insulin Secretion and Sensitivity in Black and White Female Adolescents

Background: Zinc is a micronutrient involved in the production of, and peripheral sensitivity to, pancreatic β cell-derived insulin. To our knowledge, the effect of zinc supplementation on insulin outcomes, and potential risk of diabetes, in otherwise healthy children in the United States has not been investigated.Objective: The objective of this study was to determine the influence of zinc supplementation on insulin outcomes in black and white girls in the early stages of adolescence. A secondary objective was to determine relations between baseline zinc concentrations and insulin outcomes.Methods: Healthy black and white girls aged 9-11 y were randomly assigned to daily supplementation of zinc (9 mg elemental Zn/d; n = 75; blacks: n = 35) or placebo (n = 72; blacks: n = 32) for 4 wk. Fasting serum insulin, glucose, and C-peptide were assessed at baseline and at 4 wk. C-peptide and glucose values were used to calculate the computer model-derived homeostatic model assessment of insulin resistance (HOMA2-IR). Changes in outcome measures were compared by using repeated-measures, mixed-model ANOVA.Results: Baseline plasma zinc was not correlated with C-peptide (r = -0.07), insulin (r = -0.06), or HOMA2-IR (r = -0.09) (all P > 0.05) after controlling for race and age. Treatment × time interactions for C-peptide and HOMA2-IR were not significant (both P > 0.05). Although the treatment × race × time interactions for C-peptide and HOMA2-IR were not significant (both P = 0.08), black girls who received the placebo experienced slight increases in C-peptide (15.7%) and HOMA2-IR (17.7%) (P = 0.06).Conclusions: Four weeks of zinc supplementation had no effect on insulin outcomes in healthy black and white early-adolescent girls, although C-peptide and HOMA2-IR tended to increase in black girls who received placebo. Additional trials that are appropriately powered should further explore the effect of zinc on markers of diabetes risk, and whether race affects this relation. This trial was registered at clinicaltrials.gov as NCT01892098.

Associations between dietary intakes of iron, copper and zinc with risk of type 2 diabetes mellitus: A large population-based prospective cohort study

BACKGROUND & AIMS

Abnormal homeostasis of iron, copper and zinc has been included in the pathogenesis of type 2 diabetes mellitus (T2DM). However, the evidence of associations between dietary intakes of these elements and T2DM is limited. We thought to examine the association between dietary intakes of iron, copper and zinc with risk of T2DM in Japanese population.

METHODS

A prospective study encompassing 16,160 healthy Japanese men and women aged 40-65 years in whom the associations between dietary intakes of iron, copper and zinc, determined by a validated self-administered food frequency questionnaire, with risk of 5-year cumulative incidence of validated physician-diagnosed T2DM, were evaluated by logistic regression model.

RESULTS

We ascertained 396 self-reported new cases of diabetes within 5-year period. Dietary intakes of iron (total and nonheme but not heme iron) and copper were positively associated with risk of T2DM; the multivariable OR in the highest versus lowest quartiles of intakes were 1.32 (1.04, 1.70; P-trend = 0.03) and 1.55 (1.13, 2.02; P-trend = 0.003), respectively. These associations were more evident in the high risk group; older, overweight, smokers and those with family history of diabetes. The dietary intake of zinc was inversely associated with risk of T2DM; the multivariable OR was 0.64 (0.54, 1.00; P-trend = 0.003), and such association was evident among younger subjects (age 40-55 years) only.

CONCLUSIONS

Dietary intakes of iron and copper were associated with a higher risk, while dietary intake of zinc was associated with a reduced risk of T2DM in Japanese population.

Zinc stimulates glucose consumption by modulating the insulin signaling pathway in L6 myotubes: essential roles of Akt-GLUT4, GSK3β and mTOR-S6K1

The present study was performed to evaluate the insulin-like effects of zinc in normal L6 myotubes as well as its ability to alleviate insulin resistance. Glucose consumption was measured in both normal and insulin-resistant L6 myotubes. Western blotting and immunofluorescence revealed that zinc exhibited insulin-like glucose transporting effects by activating key markers that are involved in the insulin signaling cascade (including Akt, GLUT4 and GSK3β), and downregulating members of the insulin signaling feedback cascade such as mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase (S6K1). In normal L6 myotubes, zinc enhanced glucose consumption via a mechanism that might involve the activation of Akt phosphorylation, glucose transporter 4 (GLUT4) translocation and GSK3β phosphorylation. In contrast, zinc exerted insulin-mimetic effects in insulin-resistant L6 myotubes by upregulating Akt phosphorylation, GLUT4 translocation and GSK3β phosphorylation, and downregulating the expression of mTOR and S6K1. In conclusion, zinc might enhance glucose consumption by modulating insulin signaling pathways including Akt-GLUT4, GSK3β, mTOR and S6K1.

Correlation Analysis of Exercise-Induced Changes in Plasma Trace Element and Hormone Levels During Incremental Exercise in Well-Trained Athletes

This study analyzes the relationship between hormonal changes induced by exercise and variations in trace elements associated with oxidative stress during incremental exercise. Nineteen well-trained endurance athletes performed a cycle ergometer test: after a warm-up of 10 min at 2.0 W kg(-1), workload increased by 0.5 W kg(-1) every 10 min until exhaustion. The analysis was controlled for prior diet and activity patterns, levels of exercise training, and time of day (circadian rhythms). Whole blood lactate concentration and plasma concentrations of ions (Zn, Se, Mn, and Co), insulin, glucagon, aldosterone, thyroid stimulating hormone (TSH), calcitonin, and parathyroid hormone (PTH) were measured at rest; at the end of each stage; and 3, 5, and 7 min post-exercise. The statistical analysis involved paired non-parametric tests and correlation coefficients. No significant differences were found in Mn or Co levels as a function of exercise intensity. Zn and Se levels at the end of the exercise protocol and over the recovery time were significantly different to baseline. Further, Zn levels were significantly correlated with aldosterone, calcitonin, and PTH levels, while Se levels were associated with aldosterone, calcitonin, and TSH levels. Our results indicate several different patterns of association between acute changes in hormone concentrations and variations in trace element concentrations related to oxidative stress during submaximal exercise.

Gene expression of the zinc transporter ZIP14 (SLC39a14) is affected by weight loss and metabolic status and associates with PPARγ in human adipose tissue and 3T3-L1 pre-adipocytes

Background

The expansion and function of adipose tissue are important during the development of insulin resistance and inflammation in obesity. Zinc dyshomeostasis is common in obese individuals. In the liver, zinc influx transporter ZIP14, affects proliferation and glucose metabolism but the role of ZIP14 in adipose tissue is still unknown. This study investigates ZIP14 gene expression in human adipose tissue before and after weight loss as well as the regulation of ZIP14 during early adipogenesis.

Methods

Fourteen obese individuals were investigated before and after a 10 week weight loss intervention and compared to 14 non-obese controls. Gene expressions of ZIP14 and peroxisome proliferator-activated receptor γ (PPARγ) were measured in subcutaneous adipose tissue and correlated with metabolic and inflammatory markers. Further, we investigated gene expression of ZIP14 and PPARγ during early adipogenesis of 3T3-L1 pre-adipocytes, together with an in silico analysis of PPARγ binding motifs in the promoter sequence of ZIP14.

Results

ZIP14 was down-regulated in obese individuals compared to non-obese controls (p = 0.0007) and was up-regulated after weight loss (p = 0.0005). Several metabolic markers of clinical importance, including body mass index, triglyceride, and insulin resistance, were inversely correlated with ZIP14. During early adipogensis an up-regulation of ZIP14 gene expression was found. PPARγ gene expression was positively correlated with the ZIP14 gene expression in both adipose tissue and during adipogenesis. However, in silico analysis revealed that the ZIP14 promoter does not contain PPARγ-binding motifs.

Conclusions

We hypothesize that ZIP14-mediated zinc influx might directly influence PPARγ activity and that ZIP14 may regulate expansion and function of adipose tissue and serve as a potential biomarker for metabolic stress.

Electronic supplementary material

The online version of this article (doi:10.1186/s40608-015-0076-y) contains supplementary material, which is available to authorized users.

Magnesium, zinc, and chromium levels in children, adolescents, and young adults with type 1 diabetes

BACKGROUND & AIMS

Several trace elements are involved in insulin signal transduction and glucose metabolism. Our aim for this present study was to determine the levels of three important elements-magnesium, chromium, and zinc-as well as one oxidative stress marker-malondialdehyde (MDA)-in young type 1 diabetic patients at different periods of their growth, and to realize the relationships between trace elements, oxidative stress, and growth stages.

METHODS

A total of 88 patients with type 1 diabetes mellitus in different growth stages and 76 gender- and age-matched healthy subjects were included in this study. The levels of MDA were measured through HPLC using a C-18 column. Zinc, magnesium, and chromium concentrations in serum were assessed using atomic absorption spectrophotometry.

RESULTS

We found higher levels of blood malondialdehyde (MDA; p < 0.001), significantly lower levels of magnesium (p < 0.001), and no differences in zinc and chromium levels (p = 0.153 and 0.515, respectively) in younger type 1 diabetic subjects relative to those of control subjects. Only 3.4% (3/88) of younger diabetic subjects exhibited hypomagnesemia; similar results were obtained when comparing different subgroups: children, adolescents, and adults. We also observed no differences in the levels of the three elements between the genders and among the growth stages (p > 0.05) of the diabetic subjects. There were no correlations between the three trace elements and HbA1C, diabetes duration, and insulin dose/BMI (all p > 0.05), but there was a significant difference between zinc levels and insulin dose/BMI (p = 0.043) in the diabetic patients.

CONCLUSIONS

We found elevated blood MDA, decreased magnesium, and no changes in zinc and chromium levels in younger type 1 diabetic subjects relative to those of control subjects. Only 3.4% of younger diabetic subjects exhibited hypomagnesemia. Whether magnesium supplementation is suitable for improving insulin sensitivity and decreasing oxidative stress and inflammation will require confirmation through additional studies.

Serum zinc concentration is inversely associated with insulin resistance but not related with metabolic syndrome in nondiabetic Korean adults

Although zinc was known to be associated with insulin metabolism and diabetes, the relationship of serum zinc concentration with insulin resistance (IR) and metabolic syndrome (MetS) was not well investigated in general population. The aim of this study is to evaluate the relationships of serum zinc concentration with IR and MetS in a nondiabetic adult population. This cross-sectional study included 656 men and 825 women who were nondiabetic adults from the fifth Korea National Health and Nutrition Examination Survey conducted in 2010. Serum zinc concentration and metabolic parameters were measured. IR was estimated by homeostatic model assessment (HOMA2). MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. Serum zinc concentration was negatively correlated with homeostasis model assessment for insulin resistance (HOMA2-IR) in men (r = -0.104, P = 0.008), but not in women. After adjusting for conventional cardiovascular risk factors, the inverse correlation was significant in both men and women (B = -0.262, SE = 0.060 for men, and B = -0.129, SE = 0.052 for women). However, serum zinc concentration was not different between the groups with and without MetS (P = 0.752 for men and P = 0.371 for women). In conclusion, serum zinc concentration was inversely associated with IR but not related to MetS in nondiabetic adult population.

Zinc, iron and vitamins A, C and e are associated with obesity, inflammation, lipid profile and insulin resistance in Mexican school-aged children

The objective of this cross-sectional study was to evaluate the relationship between micronutrient status and obesity, lipids, insulin resistance and chronic inflammation in children. Weight, height, waist circumference and body composition (dual-energy X-ray absorptiometry (DEXA)) were determined in 197 school-aged children. Lipids, glucose, insulin, C-reactive protein (CRP), zinc, iron and vitamins A, C and E were analyzed in blood. Vitamin C and vitamin E:lipids were negatively associated with Body Mass Index (BMI), waist-to-height ratio (WHR) and body and abdominal fat (p < 0.05). Vitamin A was positively associated with BMI, BMI-for-age, WHR and abdominal fat (p < 0.05). Iron and vitamin E:lipids were negatively associated with insulin (p < 0.05). Vitamins A, C and E and iron were negatively associated with CRP (p < 0.05). Interaction analysis showed that children who were overweight and obese who also had low concentrations of vitamin A had higher CRP and lower triglycerides (p < 0.1), children with low vitamin E had significantly lower glucose and triglycerides (p < 0.1) and higher low-density lipoprotein (LDL) concentrations (p < 0.05), and children with low zinc concentrations had higher insulin resistance compared with children with adequate weight (p < 0.05). In conclusion, low vitamin C concentration and vitamin E:lipids were associated with obesity. Furthermore, low concentrations of zinc, vitamins A and E in children who were overweight and obese were associated with lipids, inflammation and insulin resistance.

Dietary zinc intake is inversely associated to metabolic syndrome in male but not in female urban adolescents

OBJECTIVE

To evaluate the relationship of copper and zinc dietary intakes with metabolic syndrome (MetS) in adolescents.

METHODS

The sample consisted of 1,311 adolescents aged 11-16 years, and MetS definition by de Ferranti et al. was used. Nutritional intakes, anthropometrical and biochemical markers were measured.

RESULTS

In males, highest quartile of zinc intake was inversely associated with MetS without and with adjustment by covariables. Without adjustment, highest quartile of copper intake was inversely associated (marginal significance) with MetS, but with adjustment, the relationship was not maintained. Likewise in male gender, elevated waist circumference was the only MetS component inversely associated with highest quartiles of zinc (without and with adjustment) and copper (significant in crude analysis and marginal significant in adjustment by covariables) intakes. In the girls, only waist circumference was significant and inversely associated with highest quartiles of zinc and copper intakes but the association did not remain significant after adjustments.

DISCUSSION

In the adolescents of this study, zinc intake could be more associated to a clustering of anthropometric, vascular, and metabolic alterations than to these alterations separately, and also it is inversely related to this clustering (MetS). However, studies in other populations are necessary to confirm and explain the finding of exclusive association zinc intake-MetS in male gender adolescents. Further research is required to explore biomarkers of physiological processes (antioxidant function, blood flow regulation, and epigenetic modulation dependent of zinc) in relation to zinc intake and MetS in pediatric and adult populations.

Changes in mineral status are associated with improvements in insulin sensitivity in obese patients following L-arginine supplementation

PURPOSE

The aim of this study is to evaluate the long-term influence of L-arginine intake on mineral concentration in patients with obesity and to assess the changes in lipid serum levels, fat content, and insulin resistance that result.

METHODS

A randomized double-blind placebo-controlled study was conducted. 88 obese patients were randomly assigned to receive either 9 g of L-arginine or placebo daily, for 6 months. At baseline and after 6 months, selected anthropometrical measurements and blood biochemical analyses were performed and mineral levels were assessed. To assess insulin sensitivity, the gold-standard euglycemic clamp methodology was used.

RESULTS

We found that 6 months of L-arginine supplementation resulted in significant increases in insulin sensitivity (Δ1.1 mg/kg/min, P < 0.01) and zinc levels (Δ1.5 μmol/L, P < 0.001). Moreover, a positive correlation between the change in zinc concentration in serum and the change in insulin sensitivity was observed (R = 0.80, P < 0.01). In the group of patients treated with L-arginine, a negative correlation between the change in zinc concentration in serum and the change in body fat content was noted (R = -0.38, P < 0.05).

CONCLUSIONS

L-Arginine supplementation affects zinc status in obese patients. One beneficial influence is related to the improvements in insulin sensitivity.