Nutritional zinc status in weaning infants: association with iron deficiency, age, and growth profile

Overnutrition is a risk factor for iron, but not for zinc or vitamin A deficiency in children and young people: a systematic review and meta-analysis

INTRODUCTION

Traditionally associated with undernutrition, increasing evidence suggests micronutrient deficiencies can coexist with overnutrition. Therefore, this work aimed to systematically review the associations between iron, zinc and vitamin A (VA) status and weight status (both underweight and overweight) in children and young people.

METHODS

Ovid Medline, Ovid Embase, Scopus and Cochrane databases were systematically searched for observational studies assessing micronutrient status (blood, serum or plasma levels of iron, zinc or VA biomarkers) and weight status (body mass index or other anthropometric measurement) in humans under 25 years of any ethnicity and gender. Risk of bias assessment was conducted using the American Dietetic Association Quality Criteria Checklist. Where possible, random effects restricted maximum likelihood meta-analyses were performed.

RESULTS

After screening, 83 observational studies involving 190 443 participants from 44 countries were identified, with many studies having reported on more than one micronutrient and/or weight status indicator. Iron was the most investigated micronutrient, with 46, 28 and 27 studies reporting data for iron, zinc and VA status, respectively. Synthesising 16 records of OR from seven eligible studies, overnutrition (overweight and obesity) increased odds of iron deficiency (ID) (OR (95% CI): 1.51 (1.20 to 1.82), p<0.0001, I2=40.7%). Odds appeared to be higher for children living with obesity (1.88 (1.33 to 2.43), p<0.0001, I2=20.6%) in comparison to those with overweight (1.31 (0.98 to 1.64), p<0.0001, I2=40.5%), although between group differences were not significant (p=0.08).

CONCLUSIONS

Overnutrition is associated with increased risk of ID, but not zinc or VA deficiencies, with an inverted U-shaped relationship observed between iron status and bodyweight. Our results highlight significant heterogeneity in the reporting of micronutrient biomarkers and how deficiencies were defined. Inflammation status was rarely adequately accounted for, and the burden of ID may well be under-recognised, particularly in children and young people living with overnutrition.

PROSPERO REGISTRATION NUMBER

CRD42020221523.

Growth, Nutritional Status, and Dietary Intake Patterns Associated With Prolonged Breastfeeding in Young Korean Children: A Nationwide Cross-Sectional Study

BACKGROUND

Although the optimal duration of breastfeeding remains unclear, breastfeeding is generally recommended exclusively for the first 6 months of life, which continues into late infancy. However, the awareness regarding the effects of long-term breastfeeding is relatively low compared with that of breastfeeding in early infancy. We aimed to investigate the growth and nutritional characteristics of the children with prolonged breastfeeding (PBF) over 1 year.

METHODS

This cross-sectional study was based on the data of children aged 12 to 23 months from the National Health and Nutrition Examination Survey (2010-2020) conducted by the Korean Center for Disease Control and Prevention. Data on anthropometric measurements, dietary behavior, and food and nutrient intake were extracted, and the association between PBF and growth, nutritional status, and dietary patterns were analyzed.

RESULTS

Of the 872 children with a birth weight of ≥ 2.5 kg in the final analysis, 34.2% continued breastfeeding over 12 months of age, and their median breastfeeding duration was 14.2 months. Children with PBF were more likely to have lower current body weight (P < 0.001) and weight gain (P < 0.001), lower daily protein (P = 0.012), calcium (P < 0.001), and iron (P < 0.001) intake per calorie compared with children weaned by 12 months of age or those who were never breastfed. Furthermore, they were started on complementary food at 6 months or later rather than 4-5 months (P < 0.001), consumed cow's milk earlier (P = 0.012), and consumed probiotics as dietary supplements (P < 0.001) significantly less commonly. When comparing the intake of food groups, children with PBF had a significantly higher intake of cereals and grains (P = 0.023) and fruits (P = 0.020) and a significantly lower intake of bean products (P = 0.020) and milk and dairy products (P = 0.003).

CONCLUSION

Korean children who continued breastfeeding over 12 months of age showed distinct characteristics in terms of growth, nutritional status, and dietary patterns in the second year of life compared to children who did not. Long-term additional research on their growth and nutritional status may be needed; however, these findings are significant as important fundamental data for nutritional counseling to establish healthy PBF.

Plasma and Nail Zinc Concentrations, But Not Hair Zinc, Respond Positively to Two Different Forms of Preventive Zinc Supplementation in Young Laotian Children: a Randomized Controlled Trial

Plasma zinc concentrations (PZC) have been shown to significantly increase during zinc supplementation. This study investigated the effects of daily preventive zinc supplementation on hair and nail zinc concentrations compared with a control group. In a randomized controlled trial, 6- to 23-month-old children (n = 3407) in Lao PDR were randomly assigned to one of four groups and followed for ~ 36 weeks: daily preventive zinc dispersible tablet (7 mg/d; PZ), daily micronutrient powder (10 mg zinc/d; MNP), therapeutic zinc supplements for diarrhea treatment (20 mg/d for 10 days; TZ), or daily placebo powder (Control). Plasma, hair, and nail zinc concentrations were assessed in a sub-sample of participants (n = 457) at baseline and endline. At baseline, 75% of children had low PZC (< 65 μg/dL). At endline, geometric mean (95% CI) PZC were greater in the PZ and MNP groups compared with the TZ and control groups (P < 0.01), but hair zinc concentrations did not differ among groups (P = 0.99). Nail zinc concentrations were marginally higher in the PZ (115.8 (111.6, 119.9) μg/g) and the MNP (117.8 (113.3, 122.3) μg/g) groups than in the TZ group (110.4 (106.0, 114.8) μg/g; P = 0.055) at endline. This study does not support the use of hair zinc as a biomarker of zinc exposure in young children. However, it provides some evidence that zinc concentrations in nails may respond to supplemental zinc interventions and supports the need for collecting additional data on this emerging biomarker.

Hair Mineral and Trace Element Contents as Reliable Markers of Nutritional Status Compared to Serum Levels of These Elements in Children Newly Diagnosed with Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) are at high risk for nutritional deficiencies because of long-term inflammation in the gut mucosa and decreased oral intake. Because inflammation responses affect serum micronutrient concentrations, serum levels are limited in reflecting body nutrient status in acute and chronic illness. We investigated the usefulness of measuring trace elements in hair as reliable markers of nutritional status compared to serum levels in children with IBD. We retrospectively analyzed pediatric patients newly diagnosed with Crohn's disease (n = 49) and ulcerative colitis (n = 16) and controls (n = 29) from 2012 to 2016. Serum micronutrient levels, inflammatory markers, and hair trace element content were evaluated and compared at the time of diagnosis and before initiating treatment. Serum calcium (p < 0.001), iron (p < 0.001), zinc (p = 0.013), selenium (p = 0.008), albumin (p < 0.001), prealbumin (p < 0.001), hemoglobin and hematocrit (p < 0.001), and WBC (p = 0.001) and lymphocytes (p < 0.001) differed significantly between the groups. After adjustment for the erythrocyte sedimentation rate, serum zinc and selenium levels were no longer significantly different between the groups (p < 0.062 and p < 0.057, respectively). Following hair analysis for mineral and trace elements, iron (p = 0.033), selenium (p = 0.017), and manganese (p = 0.009) differed significantly between the groups. Serum micronutrient levels need cautious interpretation in conjunction with inflammatory markers. Hair mineral and trace element measurement may support understanding micronutrient status in children with IBD.

Is Infant/Toddler Anemia a Problem across Rural China? A Mixed-Methods Analysis

In the past, iron-deficiency anemia in children has had a widespread presence in rural China. Given the recent economic growth in China, it is unclear if anemia among infants/toddlers remains a problem. The objective of this study is to measure the anemia rate in rural Chinese infants/toddlers across four major subpopulations and attempt to discover the sources of anemia. We use a mixed-methods approach combining quantitative data on 2909 rural Chinese infants/toddlers and their families with qualitative interviews with 84 caregivers of infants aged 6 to 30 months. Quantitative analysis indicates that the overall prevalence of anemia (43%) within sampled infants/toddlers was high, especially in comparison to the low rates of stunting (2⁻5%), being underweight (2%), and wasting (2⁻4%). These findings suggest that in rural China, anemia stems from the poor quality of the diets of infants/toddlers, rather than insufficient quantities of food being consumed. Qualitative analysis illustrates the factors that are contributing to anemia. Caregivers do not understand the causes of this condition, the symptoms that would lead one to recognize this condition, or the steps needed to treat their child with this condition. The findings offer a comprehensive understanding of the limited awareness of anemia among rural Chinese caregivers.

Low-Level Toxic Metal Exposure in Healthy Weaning-Age Infants: Association with Growth, Dietary Intake, and Iron Deficiency

Even low levels of toxic metal exposure (As, Cd, Hg, and Pb) in infancy might be harmful to children's development. This study investigated toxic metal exposure on healthy weaning-age infants and its relationship with growth, diet, and iron/anemia status. The weight, height, head circumference, whole blood levels of four toxic metals, hemoglobin, and serum ferritin of healthy infants was measured. Among 210 infants with a median age of 11.4 months (interquartile range: 10.5-12.0), the median levels of As, Cd, Hg, and Pb were 1.2 μg/L, 0.05 μg/L, 0.8 μg/L, and 0.83 μg/dL, respectively. In adjusted linear regression models, post-birth weight gain (Pb) and current head circumference (As, Pb) were negatively associated with toxic metal levels. In multiple linear regression or logistic regression analysis, the duration of breastfeeding (all four metals), perceived adequacy of rice-based food intake (As), regular fish intake (As, Hg), and iron deficiency with/without anemia (Cd, Pb) were associated with increased toxic metal levels. Although levels of toxic metals may not usually be high in this population, individual exposure risk may need to be assessed after considering the type of feeding or intake of complementary foods and the iron/anemia status while evaluating growth status during late infancy.

Serum and Hair Mineral Levels in Children with Failure to Thrive According to the Type of Feeding Difficulties

This study evaluated serum and hair mineral and trace element levels as well as levels of other nutritional factors affecting growth and appetite in young children with non-organic failure to thrive (NOFTT) based on the presence or types of feeding difficulty (FD). Between August 2012 and July 2015, 136 children less than 6 years of age with NOFTT were included. FD was diagnosed based on Wolfson criteria and divided into subtypes according to Chatoor's classification. Clinical data were reviewed, and serum and hair mineral levels were measured. Of all assessed serum and hair minerals, only hair sulfur contents differed significantly between subjects with and without infantile anorexia (39,392 ± 2211 vs. 40,332 ± 2551 μg/g, P = 0.034). There were no differences in serum and hair mineral levels between children with and without sensory food aversion. Hair copper contents were significantly lower in children with FD of reciprocity (12.3 ± 6.0 vs. 22.4 ± 25.1 μg/g, P = 0.049). While hair zinc contents were also lower, the difference was not statistically significant (49.2 ± 26.8 vs. 70.6 ± 41.0 μg/g, P = 0.055). Only hair manganese contents were significantly lower in children with posttraumatic FD (0.12 ± 0.04 vs. 0.26 ± 0.73 μg/g, P = 0.037). In conclusion, there were no differences in most serum and hair mineral levels in children with NOFTT, except for relatively lower hair levels of sulfur, copper and possibly zinc, and manganese in infantile anorexia, reciprocity, and posttraumatic types of FD, respectively.

An Assessment of the Consumption of Energy and Selected Minerals and Their Content in the Hair of Children Aged 1-4 Years

The aim of this study was to assess the consumption of energy and selected minerals (Ca, Mg, Fe, Zn, Cu) and their content in the hair of children aged 1-4 years. Seventy-five children were divided into three age subgroups: 12-24-month-olds, 25-36-month-olds and 37-48-month-olds. The data on energy intake and consumption of nutrients were obtained by means of a nutritional interview. The content of elements in the hair was measured by means of flame atomic absorption spectrometry (AAS) with an AAS-3 spectrophotometer (Zeiss). The daily food rations of children aged 12-36 months were characterised by adequate energy value, but the values of Ca and K were too low, whereas the content of Mg, Zn and Cu was high. On the other hand, the daily food rations of children aged 37-48 months provided sufficient amounts of Mg and Zn, but the value of Cu was too high, whereas energy, Ca, K and Fe were too low. About 42.7% of the children under study were characterised by an abnormal state of nutrition. An inadequately balanced diet needs to be corrected by educating parents or guardians in appropriate nutrition. There are significant correlations (r > 0.9) between the supply of Ca in the diet of children aged 1-4 years and the content of this element in their hair.

Mercury Exposure in Healthy Korean Weaning-Age Infants: Association with Growth, Feeding and Fish Intake

Low-level mercury (Hg) exposure in infancy might be harmful to the physical growth as well as neurodevelopment of children. The aim of this study was to investigate postnatal Hg exposure and its relationship with anthropometry and dietary factors in late infancy. We recruited 252 healthy Korean infants between six and 24 months of age from an outpatient clinic during the 2009/2010 and 2013/2014 seasons. We measured the weight and height of the infants and collected dietary information using questionnaires. The Hg content of the hair and blood was assessed using inductively coupled plasma mass spectroscopy. The geometric mean Hg concentration in the hair and blood was 0.22 (95% confidence interval: 0.20–0.24) µg/g and 0.94 (n = 109, 95% confidence interval: 0.89–0.99) µg/L, respectively. The hair Hg concentration showed a good correlation with the blood Hg concentration (median hair-to-blood Hg ratio: 202.7, r = 0.462, p < 0.001) and was >1 µg/g in five infants. The hair Hg concentration showed significant correlations with weight gain after birth (Z-score of the weight for age—Z-score of the birthweight; r = −0.156, p = 0.015), the duration (months) of breastfeeding as the dominant method of feeding (r = 0.274, p < 0.001), and the duration of fish intake more than once per week (r = 0.138, p = 0.033). In an ordinal logistic regression analysis with categorical hair Hg content (quartiles), dietary factors, including breastfeeding as the dominant method of feeding in late infancy (cumulative odds ratio: 6.235, 95% confidence interval: 3.086–12.597, p < 0.001) and the monthly duration of fish intake more than once per week (cumulative odds ratio: 1.203, 95% confidence interval: 1.034–1.401; p = 0.017), were significantly associated with higher hair Hg content. Weight gain after birth was not, however, significantly associated with hair Hg content after adjustment for the duration of breastfeeding as the dominant method of feeding. Low-level Hg exposure through breastfeeding and fish intake as a complementary food did not directly affect anthropometry in this population. If prolonged breastfeeding is expected, however, the Hg exposure through fish intake may need to be monitored for both mothers and infants.