Effect of oral zinc supplementation on the growth of preterm infants

Cord levels of zinc and copper in relation to maternal serum levels in different gestational ages

Background

A few published data on maternal and cord levels of zinc and copper with conflicting results were reported. We aimed to measure zinc and copper levels in the maternal blood and cord blood of newborns and correlate their levels with the gestational age and anthropometric measurements. This cross-sectional study included 75 full-term and preterm neonates and their mothers. These neonates were divided into 2 groups according to their gestational age. Serum levels of copper and zinc were estimated for the mothers of the studied neonates as well as their cord samples. This was done using atomic absorption spectrophotometry.

Results

The mean cord serum zinc in full term was 0.88 ± 0.18 μg/ml whereas in preterms was 0.73 ± 0.13 μg/ml. The mean cord copper in full term was 1.37 ± 0.26 μg/ml, whereas in preterms was 0.75 ± 0.28 μg/ml. Comparison between cord zinc and copper levels and maternal levels were statistically significant (p < 0.001). A significant positive correlation was found between zinc levels in neonates and their mothers (r 0.644; p < 0.000) and a similar positive correlation was found between copper levels in neonates and their mothers (r 0.625; p 0.000). A highly significant positive correlation was found between cord zinc and copper and anthropometric measurements.

Conclusion

The present work draws our attention to the significant correlation between trace elements in pregnant mothers and fetal development. Also, prematurity adversely influences zinc and copper levels in neonates.

Enteral zinc supplementation for prevention of morbidity and mortality in preterm neonates

BACKGROUND

Preterm and low birth weight infants are born with low stores in zinc, which is a vital trace element for growth, cell differentiation and immune function. Preterm infants are at risk of zinc deficiency during the postnatal period of rapid growth. Systematic reviews in the older paediatric population have previously shown that zinc supplementation potentially improves growth and positively influences the course of infectious diseases. In paediatric reviews, the effect of zinc supplementation was most pronounced in those with low nutritional status, which is why the intervention could also benefit preterm infants typically born with low zinc stores and decreased immunity.

OBJECTIVES

To determine whether enteral zinc supplementation, compared with placebo or no supplementation, affects important outcomes in preterm infants, including death, neurodevelopment, common morbidities and growth.

SEARCH METHODS

Our searches are up-to-date to 20 February 2020. For the first search, we used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2017, Issue 8), MEDLINE via PubMed (1966 to 29 September 2017), Embase (1980 to 29 September 2017), and CINAHL (1982 to 29 September 2017). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs. We ran an updated search from 1 January 2017 to 20 February 2020 in the following databases: CENTRAL via CRS Web, MEDLINE via Ovid, and CINAHL via EBSCOhost.

SELECTION CRITERIA

We included RCTs and quasi-RCTs that compared enteral zinc supplementation versus placebo or no supplementation in preterm infants (gestational age < 37 weeks), and low birth weight babies (birth weight < 2500 grams), at any time during their hospital admission after birth. We included zinc supplementation in any formulation, regimen, or dose administered via the enteral route. We excluded infants who underwent gastrointestinal (GI) surgery during their initial hospital stay, or had a GI malformation or another condition accompanied by abnormal losses of GI juices, which contain high levels of zinc (including, but not limited to, stomas, fistulas, and malabsorptive diarrhoea).

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal. Two review authors separately screened abstracts, evaluated trial quality and extracted data. We synthesised effect estimates using risk ratios (RR), risk differences (RD), and standardised mean differences (SMD). Our primary outcomes of interest were all-cause mortality and neurodevelopmental disability. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included five trials with a total of 482 preterm infants; there was one ongoing trial. The five included trials were generally small, but of good methodological quality. Enteral zinc supplementation compared to no zinc supplementation Enteral zinc supplementation started in hospitalised preterm infants may decrease all-cause mortality (between start of intervention and end of follow-up period) (RR 0.55, 95% CI 0.31 to 0.97; 3 studies, 345 infants; low-certainty evidence). No data were available on long-term neurodevelopmental outcomes at 18 to 24 months of (post-term) age. Enteral zinc supplementation may have little or no effect on common morbidities such as bronchopulmonary dysplasia (RR 0.66, 95% CI 0.31 to 1.40, 1 study, 193 infants; low-certainty evidence), retinopathy of prematurity (RR 0.14, 95% CI 0.01 to 2.70, 1 study, 193 infants; low-certainty evidence), bacterial sepsis (RR 1.11, 95% CI 0.60 to 2.04, 2 studies, 293 infants; moderate-certainty evidence), or necrotising enterocolitis (RR 0.08, 95% CI 0.00 to 1.33, 1 study, 193 infants; low-certainty evidence). The intervention probably improves weight gain (SMD 0.46, 95% CI 0.28 to 0.64; 5 studies, 481 infants; moderate-certainty evidence); and may slightly improve linear growth (SMD 0.75, 95% CI 0.36 to 1.14, 3 studies, 289 infants; low-certainty evidence), but may have little or no effect on head growth (SMD 0.21, 95% CI -0.02 to 0.44, 3 studies, 289 infants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Enteral supplementation of zinc in preterm infants compared to no supplementation or placebo may moderately decrease mortality and probably improve short-term weight gain and linear growth, but may have little or no effect on common morbidities of prematurity. There are no data to assess the effect of zinc supplementation on long-term neurodevelopment.

Effect of Zinc Supplementation on Early Outcome of Neonatal Sepsis--A Randomized Controlled Trial

OBJECTIVE

To find the effect of zinc supplementation on the outcome of neonatal sepsis at one month of age.

METHODS

This randomized controlled trial was conducted in a tertiary care neonatal unit, enrolling neonates with clinical features of sepsis and positive blood culture or positive sepsis screening tests. The treatment group received 3 mg/kg/twice a day of zinc sulfate monohydrate orally for 10 d along with standard antibiotic therapy. The control group received standard antibiotic treatment without zinc. Samples were collected from both the groups before and after the treatment. Babies were monitored till discharge and followed up as out-patients till one month of age.

RESULTS

Demographic characteristics were similar between the cases and controls. After 10 d of treatment, the mean serum zinc level between the two groups was 737.09 ± 219.97 vs. 801.26 ± 405.56, (p = 0.20). Outcome measures like days of hospital stay (15 vs. 15; p = 0.69) and mortality rate (4.5% vs. 13.6%; p = 0.27) were not found to be significantly different between the groups. At one month of age, more number of control neonates had abnormal neurological findings as compared to the zinc supplemented group [(P = 0.02); RR (95%CI) = 0.28 (0.11-0.73)].

CONCLUSIONS

Zinc supplementation in neonates with sepsis improves the neurological status at one month of age although the mortality reduction was not statistically significant.

Biomarkers of Nutrition for Development (BOND)-Zinc Review

Zinc is required for multiple metabolic processes as a structural, regulatory, or catalytic ion. Cellular, tissue, and whole-body zinc homeostasis is tightly controlled to sustain metabolic functions over a wide range of zinc intakes, making it difficult to assess zinc insufficiency or excess. The BOND (Biomarkers of Nutrition for Development) Zinc Expert Panel recommends 3 measurements for estimating zinc status: dietary zinc intake, plasma zinc concentration (PZC), and height-for-age of growing infants and children. The amount of dietary zinc potentially available for absorption, which requires an estimate of dietary zinc and phytate, can be used to identify individuals and populations at risk of zinc deficiency. PZCs respond to severe dietary zinc restriction and to zinc supplementation; they also change with shifts in whole-body zinc balance and clinical signs of zinc deficiency. PZC cutoffs are available to identify individuals and populations at risk of zinc deficiency. However, there are limitations in using the PZC to assess zinc status. PZCs respond less to additional zinc provided in food than to a supplement administered between meals, there is considerable interindividual variability in PZCs with changes in dietary zinc, and PZCs are influenced by recent meal consumption, the time of day, inflammation, and certain drugs and hormones. Insufficient data are available on hair, urinary, nail, and blood cell zinc responses to changes in dietary zinc to recommend these biomarkers for assessing zinc status. Of the potential functional indicators of zinc, growth is the only one that is recommended. Because pharmacologic zinc doses are unlikely to enhance growth, a growth response to supplemental zinc is interpreted as indicating pre-existing zinc deficiency. Other functional indicators reviewed but not recommended for assessing zinc nutrition in clinical or field settings because of insufficient information are the activity or amounts of zinc-dependent enzymes and proteins and biomarkers of oxidative stress, inflammation, or DNA damage.

Poor zinc status in early infancy among both low and normal birth weight infants and their mothers in Delhi

BACKGROUND

Low birth weight (LBW) infants are at high risk of zinc deficiency, but there is a paucity of data on their zinc status.

OBJECTIVE

To evaluate zinc status of LBW (BW <2,500 g) and normal birth weight (NBW; BW ≥ 2,500 g) infants at birth and in early infancy.

METHODS

A total of 339 infants (LBW, n = 220; NBW, n = 119) were enrolled, and venous blood samples of mother-infant dyad were taken within 48 h of birth. Infants' levels were repeated between 2 and 10 months of age. Serum zinc levels were estimated using an inductively coupled plasma mass spectrometer. Primary outcome was zinc deficiency, defined as serum zinc <65 µg/dl.

RESULTS

Zinc results were available for 182 LBW and 103 NBW infants at birth and for 100 LBW and 66 NBW infants at follow-up with a median postnatal age of 14 and 15.5 weeks, respectively. Median zinc levels were low and comparable at birth as well as at follow-up, with zinc deficiency being present in 51.0% of LBW and 42.4% of NBW infants at birth and in 79.0% of LBW and 66.7% of NBW infants at follow-up. Zinc levels decreased significantly in both groups from birth to follow-up, irrespective of zinc multivitamin supplementation. Zinc levels of infants with BW <2,000 g at follow-up were significantly lower compared to infants with higher BW.

CONCLUSION

Zinc status was poor in many infants at birth irrespective of BW. Zinc status worsened significantly during early infancy, with infants with BW <2,000 g having the lowest zinc levels.