Multiple micronutrient supplementation improves micronutrient status in primary school children in Hai Phong City, Vietnam: a randomised controlled trial

Micronutrient deficiency and supplements in schoolchildren and teenagers

PURPOSE OF REVIEW

The essential micronutrients are corner stones in the functional and physical development. Early deficiency has life-long consequences. While awareness about iron deficiency is relatively high, it remains lower for other micronutrients. This review aims at reporting on recent data and attracting attention to the high prevalence of micronutrient deficiencies in school-age and adolescent individuals.

RECENT FINDINGS

Iron deficiency anaemia remains highly prevalent worldwide and the most frequent deficiency but can be corrected with simple tools ranging from food fortification, nutritional intervention, and to supplements. The link between micronutrient (MN) deficiency and neurobehavioral disorders is increasingly established and is worrying even in Western countries. Paediatric individuals are prone to imbalanced diets and picky eating behaviour, and their diets may then become incomplete: the highest risk for deficiency is observed for iron, zinc and vitamin D.

SUMMARY

There is not much new information, but rather confirmation of the importance of health policies. Well conducted randomized controlled trials confirm that deficiencies can be corrected efficiently including with food fortification, and result in clinical benefits. Individual complementation should be considered in children and adolescents with proven deficiency.

Plasma mineral status after a six-month intervention providing one egg per day to young Malawian children: a randomized controlled trial

Mineral deficiencies are common in children living in low-resource areas. Eggs are a rich source of essential nutrients and have been shown to improve growth in young children, although little is known about their impact on mineral status. Children aged 6-9 months (n = 660) were randomized to receive either one egg/day for 6-months or no intervention. Anthropometric data, dietary recalls, and venous blood were collected at baseline and 6-months follow-up. Quantification of plasma minerals (n = 387) was done using inductively coupled plasma-mass spectroscopy. Difference-in-difference mean plasma mineral concentrations was determined from baseline and follow-up values and assessed between groups by intention-to-treat using ANCOVA regression models. Prevalence of zinc deficiency was 57.4% at baseline and 60.5% at follow-up. Mean difference (MD) of plasma magnesium, selenium, copper, and zinc levels were not different between groups. Plasma iron concentrations were significantly lower in the intervention compared to the control group (MD = - 9.29; 95% CI: - 15.95, - 2.64). Zinc deficiency was widely prevalent in this population. Mineral deficiencies were not addressed with the egg intervention. Further interventions are needed to improve the mineral status of young children.

Long-Term Impact of Multiple Micronutrient Supplementation on Micronutrient Status, Hemoglobin Level, and Growth in Children 24 to 59 Months of Age: A Non-Randomized Community-Based Trial from Pakistan

Cost-effective interventions are needed to address undernutrition, particularly micronutrient deficiencies, which are common in children under the age of five in low- and middle-income countries. A community-based, non-randomized clinical trial was undertaken in the Kurram district of Khyber Pakhtunkhwa from January 2018 to June 2019, to evaluate the effect of locally produced micronutrient powder (local name: Vita-Mixe) on plasma micronutrient status, hemoglobin level, and anthropometric outcomes. Children aged 24–48 months old were recruited and allocated to the intervention and control arm of the study. The enrolled children in the intervention arm received one micronutrient powder (MNP) sachet for consumption on alternate days for 12 months. To assess the impact of the intervention on plasma levels of zinc, vitamin D, vitamin A, and hemoglobin level, blood samples were taken at baseline and after one year following the intervention. The analysis was conducted using Enzyme-Linked Immunosorbent Assay (ELISA), atomic absorption spectrometry, and an automated hematology analyzer. For the impact on growth parameters, the anthropometric assessment was performed using WHO standard guidelines. A 24 h dietary recall interview was used to assess the nutrient intake adequacy. Results showed that in the intervention arm, children had on average a 7.52 ng/mL (95% CI 5.11–9.92, p-value < 0.001) increase in the plasma level of vitamin A, 4.80 ng/mL (95% CI 1.63–7.95, p-value < 0.002) increase in vitamin D levels and 33.85 µg/dL (95% CI 24.40–43.30, p-value < 0.001) increase in the plasma zinc level, as well as a 2.0g/dL (95% CI 1.64–2.40, p-value < 0.001) increase in hemoglobin level. Statistically significant improvement was observed in the weight-for-height z-score (WHZ) (from −1.0 ± 0.88 to −0.40 ± 1.01, p < 0.001) and weight-for-age z-score (WAZ) (from −1.40 ± 0.50 to −1.05 ± 0.49, p < 0.001) in the intervention group compared to the control group. No statistically significant change was observed in the height-for-age z-score (HAZ) in the intervention group (p = 0.93). In conclusion, micronutrient powder supplementation is a cost-effective intervention to improve the micronutrient status, hemoglobin level, and growth parameters in under-five children, which can be scaled up in the existing health system to address the alarming rates of undernutrition in Pakistan and other developing countries.

Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age

BACKGROUND

Vitamin A deficiency (VAD) is a major public health problem in low- and middle-income countries, affecting 190 million children under five years of age and leading to many adverse health consequences, including death. Based on prior evidence and a previous version of this review, the World Health Organization has continued to recommend vitamin A supplementation (VAS) for children aged 6 to 59 months. The last version of this review was published in 2017, and this is an updated version of that review.

OBJECTIVES

To assess the effects of vitamin A supplementation (VAS) for preventing morbidity and mortality in children aged six months to five years.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, six other databases, and two trials registers up to March 2021. We also checked reference lists and contacted relevant organisations and researchers to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-RCTs evaluating the effect of synthetic VAS in children aged six months to five years living in the community. We excluded studies involving children in hospital and children with disease or infection. We also excluded studies evaluating the effects of food fortification, consumption of vitamin A rich foods, or beta-carotene supplementation.

DATA COLLECTION AND ANALYSIS

For this update, two review authors independently assessed studies for inclusion resolving discrepancies by discussion. We performed meta-analyses for outcomes, including all-cause and cause-specific mortality, disease, vision, and side effects. We used the GRADE approach to assess the quality of the evidence.

MAIN RESULTS

The updated search identified no new RCTs. We identified 47 studies, involving approximately 1,223,856 children. Studies were set in 19 countries: 30 (63%) in Asia, 16 of these in India; 8 (17%) in Africa; 7 (15%) in Latin America, and 2 (4%) in Australia. About one-third of the studies were in urban/periurban settings, and half were in rural settings; the remaining studies did not clearly report settings. Most studies included equal numbers of girls and boys and lasted about one year. The mean age of the children was about 33 months. The included studies were at variable overall risk of bias; however, evidence for the primary outcome was at low risk of bias. A meta-analysis for all-cause mortality included 19 trials (1,202,382 children). At longest follow-up, there was a 12% observed reduction in the risk of all-cause mortality for VAS compared with control using a fixed-effect model (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.83 to 0.93; high-certainty evidence). Nine trials reported mortality due to diarrhoea and showed a 12% overall reduction for VAS (RR 0.88, 95% CI 0.79 to 0.98; 1,098,538 children; high-certainty evidence). There was no evidence of a difference for VAS on mortality due to measles (RR 0.88, 95% CI 0.69 to 1.11; 6 studies, 1,088,261 children; low-certainty evidence), respiratory disease (RR 0.98, 95% CI 0.86 to 1.12; 9 studies, 1,098,538 children; low-certainty evidence), and meningitis. VAS reduced the incidence of diarrhoea (RR 0.85, 95% CI 0.82 to 0.87; 15 studies, 77,946 children; low-certainty evidence), measles (RR 0.50, 95% CI 0.37 to 0.67; 6 studies, 19,566 children; moderate-certainty evidence), Bitot's spots (RR 0.42, 95% CI 0.33 to 0.53; 5 studies, 1,063,278 children; moderate-certainty evidence), night blindness (RR 0.32, 95% CI 0.21 to 0.50; 2 studies, 22,972 children; moderate-certainty evidence), and VAD (RR 0.71, 95% CI 0.65 to 0.78; 4 studies, 2262 children, moderate-certainty evidence). However, there was no evidence of a difference on incidence of respiratory disease (RR 0.99, 95% CI 0.92 to 1.06; 11 studies, 27,540 children; low-certainty evidence) or hospitalisations due to diarrhoea or pneumonia. There was an increased risk of vomiting within the first 48 hours of VAS (RR 1.97, 95% CI 1.44 to 2.69; 4 studies, 10,541 children; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

This update identified no new eligible studies and the conclusions remain the same. VAS is associated with a clinically meaningful reduction in morbidity and mortality in children. Further placebo-controlled trials of VAS in children between six months and five years of age would not change the conclusions of this review, although studies that compare different doses and delivery mechanisms are needed. In populations with documented VAD, it would be unethical to conduct placebo-controlled trials.