Defining Optimal Cobalamin Status for Neonates and Infants

BACKGROUND

An optimal cobalamin status is necessary for normal neurodevelopment.

OBJECTIVE

To give a description of the epidemiology, pathophysiology and diagnostic challenges related to cobalamin insufficiency in neonates and infants in order to prevent its occurence.

RESULTS

Inadequate cobalamin status is prevalent among neonates and young infants, due to a high prevalence of maternal cobalamin deficiency, exclusive breastfeeding for extended periods and late introduction of animal food. Cobalamin insufficiency is associated with delayed neurodevelopment and subtle clinical symptoms like feeding difficulties, regurgitations and constipation in young infants. Early diagnosis and treatment of impaired cobalamin status is important to prevent neurologic damage.

CONCLUSION

Clinical suspicion of cobalamin insufficiency in infants should infer immediate biochemical testing and a plasma total homocysteine > 5.0 µmol/L indicate cobalamin insufficiency in need of intramuscular treatment with hydroxycobalamin, followed by introduction of animal food after 4 months of age.

Isolation and identification of zinc-chelating peptides from sea cucumber (Stichopus japonicus) protein hydrolysate

BACKGROUND

Zinc is known to play an essential role in the biological activities in the human body. In this study, a zinc-chelating peptide (ZCP) produced by Alcalase-assisted hydrolysis of the body wall of sea cucumber was isolated and identified. The ZCP was purified stepwise by ultrafiltration, anion-exchange chromatography, and gel filtration chromatography, in conjunction with ultraviolet-visual (UV-visual) spectrophotometry, which was used to analyze each purified fraction.

RESULTS

Analysis of the purified ZCP revealed that its zinc-chelating ability was 33.31%. Analysis of isothermal titration calorimetry suggested that the binding of ZCP and zinc (N ≈ 2) was endothermic, with weak binding affinity. Fourier transform infrared spectroscopy spectra (FTIR) indicated that carboxylic and amide groups in ZCP were the primary binding sites of Zn. Sequencing the result by ultra-performance liquid chromatography-quadrupole/time of flight mass spectrometry (UPLC-Q-TOF-MS/MS) showed that a representative ZCP had the sequence WLTPTYPE with a molecular weight of 1005.5 Da.

CONCLUSION

These results provide a promising foundation for the production of zinc supplements from sea-cucumber-derived ZCPs. © 2019 Society of Chemical Industry.

Biochar decreased the bioavailability of Zn to rice and wheat grains: Insights from microscopic to macroscopic scales

Zn deficiency is a critical problem for many crops and human populations worldwide. Soil biochar amendment has recently been promoted as a sustainable agricultural practice. However, its effect on the bioavailability of micronutrients (especially Zn) to crops has not been fully addressed. This study investigated the impact of long-term biochar application in soils on Zn bioavailability to rice and wheat, using field experiments, and batch sorption/desorption experiments, in combination with extended X-ray absorption fine structure spectroscopy (EXAFS). In field soils biochar amendment increased total Zn content, but significantly decreased CaCl₂-extractable Zn concentrations. Intriguingly, the uptake of Zn to wheat and rice grains was decreased. At high biochar application rates of 124 and 270t/ha the Zn concentrations in wheat grains (36.6 and 37.5mg/kg) reached a deficient level, lower than the recommended concentration of 45mg/kg. The batch experiments showed that biochar application at a cumulative rate of 10.5, 15.8, 31.5, 124, and 270t/ha significantly increased soil pH and soil organic matter (SOM) content, resulting in greater sorption and lower desorption of Zn. The EXAFS results demonstrated that the main forms of sorbed Zn were outer-sphere Zn complexes, Zn-illite, Zn-kaolinite and Zn-OM. The proportion of Zn-OM increased with increasing biochar application rates, suggesting that higher SOM might be more effective in immobilizing Zn and thus decreasing the Zn bioavailability. These results on the microscopic and macroscopic scales improved our understanding of the Zn bioavailability to crops, and raised potential concerns on the Zn deficiency in agricultural soils with long-term biochar application.

Zinc supplementation for prevention of acute respiratory infections in infants: a randomized controlled trial

OBJECTIVE

To study the effect of 2 weeks of prophylactic zinc supplementation on incidence and duration of acute respiratory infections.

DESIGN

Randomized double blind controlled trial.

SETTING

Community based; urban resettlement area in North-East Delhi, India.

PARTICIPANTS

272 children aged 6-11 months with acute respiratory infections. Children receiving zinc supplement within the past 3 months, severely malnourished, immuno-deficient, on steroid therapy, with severe illness requiring hospitalization, or children of families likely to migrate from the study area were excluded.

INTERVENTION

Placebo (syrup base) or zinc (20 mg/5 mL elemental zinc as zinc sulfate) orally given for a period of 2 weeks.

MAIN OUTCOME MEASURE(S)

Incidence, type and duration of acute respiratory infections, and adverse effects.

RESULTS

No effect on incidence of acute respiratory infections was noted. A decrease of 15% (0.78-0.94) in days and 12% (0.78-0.94) in duration of episode in acute respiratory infections was observed. Incidence of acute lower respiratory infections decreased by 62% (0.26-0.36) and the effect remained for full five months of follow up. There were no drop outs due to side effects.

CONCLUSIONS

Prophylactic zinc supplementation for two weeks may reduce the morbidity due to acute lower respiratory infections but not overall rate of acute respiratory infections in infants aged 6-11 months in similar populations.

Short-course prophylactic zinc supplementation for diarrhea morbidity in infants of 6 to 11 months

BACKGROUND

Zinc supplementation during diarrhea substantially reduces the incidence and severity of diarrhea. However, the effect of short-course zinc prophylaxis has been observed only in children >12 months of age. Because the incidence of diarrhea is comparatively high in children aged 6 to 11 months, we assessed the prophylactic effect of zinc on incidence and duration of diarrhea in this age group.

METHODS

In this randomized, double-blind, placebo-controlled trial, we enrolled infants aged 6 to 11 months from an urban resettlement colony in Delhi, India, between January 1, 2011, and January 15, 2012. We randomly assigned 272 infants to receive either 20 mg of zinc or a placebo suspension orally every day for 2 weeks. The primary outcome was the incidence of diarrhea per child-year. All analyses were done by intention-to-treat.

RESULTS

A total of 134 infants in the zinc and 124 in the placebo groups were assessed for the incidence of diarrhea. There was a 39% reduction (crude incident rate ratio [IRR] 0.61, 95% confidence interval [CI] 0.53-0.71) in episodes of diarrhea, 39% (adjusted IRR 0.61, 95% CI 0.54-0.69) in the total number of days that a child suffered from diarrhea, and reduction of 36% in duration per episode of diarrhea (IRR 0.64, 95% CI 0.56-0.74) during the 5 months of follow-up.

CONCLUSIONS

Short-course prophylactic zinc supplementation for 2 weeks may reduce diarrhea morbidity in infants of 6 to 11 months for up to 5 months, in populations with high prevalence of wasting and stunting.

Zinc supplementation for mental and motor development in children

BACKGROUND

Zinc deficiency is a significant public health problem in low- and middle-income countries. Zinc is essential for the formation and migration of neurons along with the formation of neuronal synapses. Its deficiency could interfere with the formation of neural pathways and with neurotransmission, thus affecting behavior (for example, attention, activity, engagement, temperament) and development (for example, gross and fine motor skills, social skills). Zinc supplementation provided to infants and children is a possible strategy to improve the mental and motor development of infants and children at high risk of zinc deficiency.

OBJECTIVES

To assess the effects of zinc supplementation compared to placebo on measures of psychomotor development or cognitive function in children.

SEARCH METHODS

We searched MEDLINE, PsycINFO, CINAHL and Latin American Database (LILACS) on 1 December 2011. We searched EMBASE and CENTRAL 2011 Issue 12 on 19 January 2012. We searched Dissertation Abstracts International and the metaRegister of Controlled Trials on 30 November 2011.

SELECTION CRITERIA

Randomized or quasi-randomized placebo-controlled trials involving synthetic zinc supplementation provided to infants or children (less than five years of age) were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results, selected studies, assessed the studies for their risk of bias and extracted data.

MAIN RESULTS

We included 13 trials in this review.Eight studies reported data on the Bayley Scales of Infant Development (BSID) in 2134 participants. We combined the data in a meta-analysis to assess the effect on development as measured by the Mental Development Index (MDI) and Psychomotor Development Index (PDI). There was no significant effect of zinc supplementation: the mean difference between the zinc supplementation and placebo groups on the MDI was -0.50 (95% confidence interval (CI) -2.06 to 1.06; P = 0.53; I(2) = 70%) and the mean difference between the groups for the PDI was 1.54 (95% CI -2.26 to 5.34; P = 0.43; I(2) = 93%). Most studies had low or unclear risk of bias but there was significant heterogeneity, which was not adequately explained by our subgroup analyses. The overall quality of evidence was considered 'moderate'.Two trials provided data on motor milestone attainment. There was no significant difference in the time to attainment of milestones between the placebo group and the zinc supplementation group in either of the studies.No study provided data on cognition score or intelligence quotient (IQ) or on adverse effects of zinc supplementation.

AUTHORS' CONCLUSIONS

There is no convincing evidence that zinc supplementation to infants or children results in improved motor or mental development.

Unusual low plasma levels of zinc in non-pregnant Congolese women

Zn is an essential trace element required throughout the life cycle. Although suboptimal Zn status is thought to be common in many sub-Saharan countries, there is a paucity of data in the Democratic Republic of Congo. The objective of the study was to determine Zn status in non-pregnant Congolese women. We measured plasma Zn and indicators of nutritional status (albumin, prealbumin, retinol-binding protein) and inflammation (C-reactive protein (CRP), ceruloplasmin, alpha1-acid glycoprotein (AGP)) in seventy-seven lactating and thirty non-lactating women (mean age 28 and 31 years, respectively). Blood samples were collected in summer 1989 in rural Bas-Congo during a survey on Fe status. Mean lactation period was 8.3 months. Mean parity was higher in lactating (3.6) than in non-lactating (2.2) women (P < 0.05). Mean biochemical indicators of nutritional status, CRP and ceruloplasmin were within normal range and not different between groups. Mean AGP concentrations were above normal (>1.2 g/l) and higher in lactating (1.365 g/l) than in non-lactating (1.178 g/l) women (P < 0.05). Mean Zn concentration (540 microg/l) of the overall study population was below normal (700 microg/l); and the mean was lower in lactating (455 microg/l) than in non-lactating (759 microg/l) women (P < 0.05). Multiple regression analysis suggested that parity (P < 0.05), but not inflammation, was the most important factor associated with low Zn levels. Despite the lack of data on dietary intake, the results suggest that suboptimal Zn status may be common in the studied population.

Zinc deficiency, infectious disease and mortality in the developing world

Zinc deficiency places children in many low-income countries at increased risk of illness and death from infectious diseases. Randomized controlled trials of zinc supplementation provide the best estimate of this risk through demonstrated preventive benefits. In six of nine trials that evaluated prevention of diarrhea, significantly lower incidence of diarrhea occurred in the zinc group than in the controls; a pooled analysis demonstrated 18% (95% confidence interval, 7-28%) less diarrhea. In five trials, a lower rate of pneumonia infection was found in the zinc-supplemented groups, and there was some indication of a preventive effect in three trials with a clinical malaria outcome. Zinc was also found to have a therapeutic benefit in seven trials of acute diarrhea and five of persistent diarrhea. Studies to evaluate the effect of zinc supplementation on mortality are under way, but a recently published study from India identified a 68% reduction in mortality in small-for-gestational-age term infants that were supplemented with zinc from 1 to 9 mo of age. The important effects of zinc deficiency are now clear, and nutrition programs should address this prevalent problem.

The evidence linking zinc deficiency with children's cognitive and motor functioning

The role of zinc in children's cognitive and motor functioning is usually assessed by the response to supplementation in populations thought to be zinc deficient. A review of published zinc-supplementation trials that examined behavior and development identified one trial in fetuses, six trials in infants and toddlers and three trials in school-age children. The three studies that examined activity reported that zinc supplementation was associated with more activity. Of the five studies that examined motor development in infants and toddlers, one found improvements among very low-birth-weight infants, one found improvements in the quality of motor development and three found no impact. Of the four studies that examined mental development in infants and toddlers, three found no impact of zinc supplementation and one found that zinc-supplemented children had lower scores than control children. Among school-age children, one study found no impact of zinc supplementation on cognitive performance and two found a beneficial impact of neuropsychological processes, specifically reasoning. The evidence linking zinc deficiency to children's cognitive and motor functioning suggests a relationship among the most vulnerable children but lacks a clear consensus, highlighting the need for additional research into the timing of zinc deficiency and the co-occurrence with other micronutrient deficiencies.