What Approaches are Most Effective at Addressing Micronutrient Deficiency in Children 0-5 Years? A Review of Systematic Reviews

The Chelating Ability of Plant Polyphenols Can Affect Iron Homeostasis and Gut Microbiota

In the past decades, many studies have widely examined the effects of dietary polyphenols on human health. Polyphenols are well known for their antioxidant properties and for their chelating abilities, by which they can be potentially employed in cases of pathological conditions, such as iron overload. In this review, we have highlighted the chelating abilities of polyphenols, which are due to their structural specific sites, and the differences for each class of polyphenols. We have also explored how the dietary polyphenols and their iron-binding abilities can be important in inflammatory/immunomodulatory responses, with a special focus on the involvement of macrophages and dendritic cells, and how they might contribute to reshape the gut microbiota into a healthy profile. This review also provides evidence that the axes “polyphenol–iron metabolism–inflammatory responses” and “polyphenol–iron availability–gut microbiota” have not been very well explored so far, and the need for further investigation to exploit such a potential to prevent or counteract pathological conditions.

Exploring the Complementarity of Fortification and Dietary Diversification to Combat Micronutrient Deficiencies: A Scoping Review

Achieving a balanced and diverse diet remains a challenge for many people, contributing to an ongoing burden of micronutrient deficiencies, particularly in low-income settings. Fortification or dietary diversification are common food-based approaches. We conducted a scoping review to: 1) find evidence on whether combined food-based strategies are more effective than single strategies, and 2) understand how strategies implemented together could complement each other to achieve optimal nutritional impact on populations. Peer-reviewed articles selected (n = 21) included interventions or observational studies (n = 13) and reviews (n = 8). We found little evidence of an added nutritional impact. On the other hand, it is apparent that fortification and dietary diversification target different types of settings (urban compared with rural) and foods (that is, low priced compared with highly priced). Further research is needed to understand the complementarity of these approaches and establish evidence of the effectiveness of combined strategies to foster policy adoption.

How effects on health equity are assessed in systematic reviews of interventions

BACKGROUND

Enhancing health equity is endorsed in the Sustainable Development Goals. The failure of systematic reviews to consider potential differences in effects across equity factors is cited by decision-makers as a limitation to their ability to inform policy and program decisions.  OBJECTIVES: To explore what methods systematic reviewers use to consider health equity in systematic reviews of effectiveness.

SEARCH METHODS

We searched the following databases up to 26 February 2021: MEDLINE, PsycINFO, the Cochrane Methodology Register, CINAHL, Education Resources Information Center, Education Abstracts, Criminal Justice Abstracts, Hein Index to Foreign Legal Periodicals, PAIS International, Social Services Abstracts, Sociological Abstracts, Digital Dissertations and the Health Technology Assessment Database. We searched SCOPUS to identify articles that cited any of the included studies on 10 June 10 2021. We contacted authors and searched the reference lists of included studies to identify additional potentially relevant studies.

SELECTION CRITERIA

We included empirical studies of cohorts of systematic reviews that assessed methods for measuring effects on health inequalities. We define health inequalities as unfair and avoidable differences across socially stratifying factors that limit opportunities for health. We operationalised this by assessing studies which evaluated differences in health across any component of the PROGRESS-Plus acronym, which stands for Place of residence, Race/ethnicity/culture/language, Occupation, Gender or sex, Religion, Education, Socioeconomic status, Social capital. "Plus" stands for other factors associated with discrimination, exclusion, marginalisation or vulnerability such as personal characteristics (e.g. age, disability), relationships that limit opportunities for health (e.g. children in a household with parents who smoke) or environmental situations which provide limited control of opportunities for health (e.g. school food environment).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data using a pre-tested form. Risk of bias was appraised for included studies according to the potential for bias in selection and detection of systematic reviews.  MAIN RESULTS: In total, 48,814 studies were identified and the titles and abstracts were screened in duplicate. In this updated review, we identified an additional 124 methodological studies published in the 10 years since the first version of this review, which included 34 studies. Thus, 158 methodological studies met our criteria for inclusion. The methods used by these studies focused on evidence relevant to populations experiencing health inequity (108 out of 158 studies), assess subgroup analysis across PROGRESS-Plus (26 out of 158 studies), assess analysis of a gradient in effect across PROGRESS-Plus (2 out of 158 studies) or use a combination of subgroup analysis and focused approaches (20 out of 158 studies). The most common PROGRESS-Plus factors assessed were age (43 studies), socioeconomic status in 35 studies, low- and middle-income countries in 24 studies, gender or sex in 22 studies, race or ethnicity in 17 studies, and four studies assessed multiple factors across which health inequity may exist. Only 16 studies provided a definition of health inequity. Five methodological approaches to consider health equity in systematic reviews of effectiveness were identified: 1) descriptive assessment of reporting and analysis in systematic reviews (140 of 158 studies used a type of descriptive method); 2) descriptive assessment of reporting and analysis in original trials (50 studies); 3) analytic approaches which assessed differential effects across one or more PROGRESS-Plus factors (16 studies); 4) applicability assessment (25 studies) and 5) stakeholder engagement (28 studies), which is a new finding in this update and examines the appraisal of whether relevant stakeholders with lived experience of health inequity were included in the design of systematic reviews or design and delivery of interventions. Reporting for both approaches (analytic and applicability) lacked transparency and was insufficiently detailed to enable the assessment of credibility.

AUTHORS' CONCLUSIONS

There is a need for improvement in conceptual clarity about the definition of health equity, describing sufficient detail about analytic approaches (including subgroup analyses) and transparent reporting of judgments required for applicability assessments in order to consider health equity in systematic reviews of effectiveness.

"Are We Feeding Them Enough?" Micronutrient Deficiency in Children Aged Six Months to Fourteen Years in India

In this study, we conducted a systematic literature review of the various micronutrient deficiencies (MNDs) that affect children in India and an examination of whether there is a geographic basis for MNDs.

MNDs are a common problem in the developing world, in particular, among children in South Asia. According to the United Nations Children’s Fund, millions of children suffer from stunted growth, cognitive delays, weakened immunity, and diseases because of MNDs. These physical ailments have several economic, social, and public health implications, and they can severely hamper a country’s growth. This study aims to clarify existing data on this topic and highlight the disparities between children living in urban and rural areas in India.

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to conduct this systematic literature review of a total of five studies. Study quality was assessed using appropriate checklists, and the studies strengthened the hypothesis that MNDs are common among children in India. Because the selected studies were heterogeneous, no statistical conclusions are drawn here. However, a central premise is that MNDs in children are prevalent in India and are related to poverty. No link between geographic location and MNDs is established; rather, recommendations are made for further research on the topic.

Is Vitamin A Supplementation Associated With Anemia in Children Under 5 Years of Age in Peru: Secondary Analysis of the "Demographic Health Survey" 2015-2018?

Vitamin A deficiency (VAD) affects 12% of Peruvians under 5 years of age. Recent studies have shown an association with hematopoiesis and iron metabolism. In Peru, 3-quarters of a million children have anemia. We aimed to identify an association between Vitamin A supplementation (VAS) and anemia in children under 5 years of age. A cross-sectional secondary analytical study from the Peruvian Demographic Survey and Family Health (DHS) was conducted. The primary outcome, anemia, was measured through hemoglobin concentration and adjusted by altitude. The DHS interviewer ensured the participant's VAS in the last 6 months through a structural healthcare card. The association was statistically significant using crude regression but disappeared when adjusted per socioeconomic level and gender. VAS was not significantly associated with a lower prevalence of anemia. Further studies are required to help identify the association between VAS and anemia.

Iron homeostasis in host and gut bacteria - a complex interrelationship

Iron deficiency is the most frequent nutritional deficiency in the world with an estimated 1.4 billion people affected. The usual way to fight iron deficiency is iron fortification, but this approach is not always effective and can have undesirable side effects including an increase in the growth and virulence of gut bacterial pathogens responsible for diarrhea and gut inflammation. Iron is mainly absorbed in the duodenum and is tightly regulated in mammals. Unabsorbed iron enters the colonic lumen where many microorganisms, referred to as gut microbiota, reside. Iron is essential for these bacteria, and its availability consequently affects this microbial ecosystem. The aim of this review is to provide further insights into the complex relationship between iron and gut microbiota. Given that overcoming anemia caused by iron deficiency is still a challenge today, gut microbiota could help identify more efficient ways to tackle this public health problem.

Dietary vitamin a intake, coverage of vitamin a megadose supplementation, and prevalence of vitamin a deficiency among marginalized children 6–59 months in anganwadis of Chandigarh: A multistage cluster sampling survey

Background:

Lack of recent local data regarding Vitamin A deficiency, dietary intake, and coverage of biannual high-dose Vitamin A prophylaxis among marginalized children poses challenges for policy change.

Objective:

Our study aimed to evaluate the burden of serum Vitamin A deficiency, dietary Vitamin A intake, and current Vitamin A supplementation coverage.

Methodology:

We enrolled 216 children aged 6–60 months from 30 Anganwadis of Chandigarh using two-stage cluster sampling.

Results:

Dietary intake of Vitamin A-rich foods and vegetables in the last 24 h was observed only in 20% of enrolled children. Although 79.21% (160/202) of children aged ≥9 months reported receiving Vitamin A supplementation, only 38.52% had documented record of age-appropriate complete supplementation. None of the children showed ocular manifestations of Vitamin A deficiency. For the subjects in which C-reactive protein levels were ≤5 mg/l (n = 148), 35.14% (52/148) had serum retinol ≤0.7 μmol/L and 2.03% (3/148) had serum retinol ≤0.3 μmol/L. The multivariate odds ratios (ORs) of Vitamin A deficiency (serum retinol <0.7) were 2.23 times higher in subjects with inappropriate complementary feeding (OR: 2.23; 95% confidence interval [CI]: 1.07–4.80; P = 0.035) whereas odds were significantly lower for middle (OR: 0.27; 95% CI: 0.09–0.76; P = 0.015) and higher income (OR: 0.14; 95% CI: 0.03–0.53; P = 0.005) families in reference to low-income group.

Conclusions:

Subclinical Vitamin A deficiency is still a public health crisis with suboptimal dietary intake of Vitamin A-rich foods and compromised food diversity necessitating targeted approach for marginalized children.

Zinc deficiency in low- and middle-income countries: prevalence and approaches for mitigation

This review addresses the prevalence of zinc deficiency in Low- and Middle-income Countries (LMICs) and assesses the available strategies for its alleviation. The paucity of national-level data on the zinc deficiency in LMICs is partially a result of the lack of a reliable biomarker. Zinc deficiency appears to be a public health problem in almost all the LMICs, irrespective of the recommended indicators (plasma zinc concentration, dietary zinc adequacy and stunting prevalence) used. Based on plasma/serum zinc concentration (PZC), which is the most appropriate indicator at present, the prevalence of zinc deficiency in LMICs is of concern. Among the 25 countries for which national PZC data were available, 23 had a zinc deficiency prevalence of >20% for at least one physiological group. Zinc supplementation is largely restricted as an adjunct therapy for diarrhoea management in children, and the best platform and the most effective way of preventive zinc supplementation delivery remains to be established. Impact assessment for current zinc fortification programmes in LMICs and the effectiveness of zinc supplementation as part of a multi-micronutrient powder is to be determined. Dietary diversification, though promising for LMICs, is in the nascent stages of development at present. Inclusion of meat and animal products can be an important way of improving zinc status. Programmatic experience with the promotion of home processing techniques to increase absorbable zinc in the diet is lacking. Conventional biofortification techniques are gaining recognition in LMICs; however, transgenic biofortification as a strategy remains controversial.

The Central Role of Iron in Human Nutrition: From Folk to Contemporary Medicine

Iron is a fundamental element in human history, from the dawn of civilization to contemporary days. The ancients used the metal to shape tools, to forge weapons, and even as a dietary supplement. This last indication has been handed down until today, when martial therapy is considered fundamental to correct deficiency states of anemia. The improvement of the martial status is mainly targeted with dietary supplements that often couple diverse co-factors, but other methods are available, such as parenteral preparations, dietary interventions, or real-world approaches. The oral absorption of this metal occurs in the duodenum and is highly dependent upon its oxidation state, with many absorption influencers possibly interfering with the intestinal uptake. Bone marrow and spleen represent the initial and ultimate step of iron metabolism, respectively, and the most part of body iron circulates bound to specific proteins and mainly serves to synthesize hemoglobin for new red blood cells. Whatever the martial status is, today’s knowledge about iron biochemistry allows us to embrace exceedingly personalized interventions, which however owe their success to the mythical and historical events that always accompanied this metal.

Micronutrient deficiencies and their public health implications for South-East Asia

PURPOSE OF REVIEW

Micronutrient deficiencies are highly prevalent worldwide, including in South-East Asia, and have a profound impact on public health. Most efforts towards eliminating micronutrient deficiencies have focused on vitamin A, iron, and iodine deficiency. But deficiency of other micronutrients also affect public health. The purpose of the present review is to provide an overview of micronutrient deficiency prevalence in South-East Asia and potential public health impact.

RECENT FINDINGS

Representative and up-to-date data on micronutrient status in South-East Asia is limited. Although anemia is still prevalent in South-East Asia, iron deficiency appears not to be prevalent in Cambodia, and less prevalent than thought in Vietnam and Indonesia. Estimates of prevalence of vitamin A deficiency range widely, but most recent data suggest a prevalence of deficiency in children less than 5 years of age less than 15% in most countries. Zinc deficiency is highly prevalent in the region (affecting >30% of subjects). Thiamine deficiency is highly prevalent in Cambodia, Laos, and Myanmar.

SUMMARY

A better coordination of efforts to reduce micronutrient deficiency, and a focus more inclusive for other micronutrients than iron, vitamin A, and iodine is urgently needed for South-East Asia.