Combating micronutrient deficiencies: problems and perspectives

Effects of multimicronutrient supplementation during pregnancy on postnatal growth of children under 5 years of age: a meta-analysis of randomized controlled trials

Background

The beneficial effect of antenatal multiple micronutrients supplementation on infant birth outcomes has been proposed by previous meta-analyses. However, their benefits on postnatal health of children have not been summarized. A meta-analysis of randomized controlled trials was conducted to evaluate the effect of maternal multimicronutrient supplementation on postnatal growth of children under 5 years of age.

Methods

We searched both published and ongoing trials through the PubMed, EMBASE, CENTRAL (OVID platform), Web of Science, BIOSIS Previews, Chinese Science Citation Database, Scopus, ProQuest, ClinicalTrials.gov, Chinese Biomedical Database, and WANFANG database for randomized controlled trials. Reference lists of included studies and relevant reviews were also reviewed for eligible studies. Standard mean difference (SMD) was employed as the index for continuous variables by using fixed effects models. Trend analysis by visual inspection was applied to evaluate the change of mean difference of weight and height between the groups over time.

Results

Nine trials (12 titles) from nine different countries were retrieved for analysis. Pooled results showed that antenatal multimicronutrient supplementation increased child head circumference (SMD = 0.08, 95% CI: 0.00–0.15) compared with supplementation with two micronutrient or less. No evidence was found for the benefits of antenatal multimicronutrient supplementation on weight (P = 0.11), height (P = 0.66), weight-for-age z scores (WAZ) (P = 0.34), height-for-age z scores (HAZ) (P = 0.81) and weight-for-height z scores (WHZ) (P = 0.22). A positive effect was found on chest circumference based on two included studies.

Conclusions

Antenatal multimicronutrient supplementation has a significant positive effect on head circumference of children under 5 years. No impact of the supplementation was found on weight, height, WAZ, HAZ and WHZ.

Programmatic effects of a large-scale multiple-micronutrient supplementation trial in Indonesia: using community facilitators as intermediaries for behavior change

BACKGROUND

Clinical trials can serve as an opportunity gateway for enhanced health benefits to the target population, above and beyond the specific intervention being tested.

OBJECTIVE

The Supplementation with Multiple Micronutrients Intervention Trial (SUMMIT), a randomized, controlled clinical trial in Lombok, Indonesia, found that supplementation during pregnancy with multiple micronutrients reduced 90-day infant mortality by nearly 20% as compared with iron-folic acid. This trial was designed as both a program and research trial and used community facilitators to serve as liaisons between the study and the pregnant women. This analysis documents the programmatic impacts of SUMMIT on health-seeking and early infant mortality resulting from community facilitators' field activities.

METHODS

Data on compliance, human resource practices, health-seeking, and health outcomes from the 31,290 SUMMIT enrollees were analyzed.

RESULTS

Overall compliance with either iron-folic acid or multiple micronutrients was high in the program, at 85.0%. Early prenatal care visits increased significantly. Sixty-three percent of primiparous women used a skilled birth attendant (SBA); among multiparous women, the rate of use of a SBA rose from 35% for the last birth to 53%. Use of a SBA resulted in a 30% reduction in early infant mortality (RR, 0.70; 95% CI, 0.59 to 0.83; p < .0001), independently of any reductions due to multiple micronutrients. The community facilitators played a central role in improving health-seeking; however, the quality of the community facilitators' performance was associated with the impact of the micronutrient supplement on infant health. In a subsample of community facilitators, better-performing facilitators were found to markedly improve the overall impact of the multiple micronutrients on early infant mortality (RR, 0.67; 95% CI, 0.49 to 0.92; p = .0117). In contrast, infants of women with poorly performing community facilitators were found to derive no additional benefit from the multiple micronutrients (RR, 1.04; 95% CI, 0.64 to 1.72; p = .8568).

CONCLUSIONS

Systematic enhancements to the quality of implementation of SUMMIT led to significant increases in use of SBAs at delivery, resulting in a 30% reduction in early infant mortality independent of the impact of micronutrient supplementation. Therefore, if women were to consume multiple micronutrients on a regular basis and were to use a SBA at delivery, the risk of early infant mortality could be reduced by nearly 50%. The impacts of community facilitators in effecting changes in women's health behaviors are notable and are applicable to other health programs. Enhancements to program implementation should be driven by evidence, be accountable to the communities the program serves, and be evaluated on the basis of measurable gains in health for women and children.

Effect of combining multiple micronutrients with iron supplementation on Hb response in children: systematic review of randomized controlled trials

OBJECTIVES

To study the effect of combining multiple (two or more) micronutrients with Fe supplementation on Hb response, when compared with placebo and with Fe supplementation, in children.

DATA SOURCES

Electronic databases, personal files, hand search of reviews, bibliographies of books, and abstracts and proceedings of international conferences.

REVIEW METHODS

Randomized controlled trials evaluating change in Hb levels with interventions that included Fe and multiple-micronutrient supplementation in comparison to placebo alone or Fe alone were analysed in two systematic reviews.

RESULTS

Twenty-five trials were included in the review comparing Fe and micronutrient supplementation with placebo. The pooled estimate (random effects model) for change in Hb with Fe and micronutrient supplementation (weighted mean difference) was 0.65 g/dl (95 % CI 0.50, 0.80, P < 0.001). Lower baseline Hb, lower height-for-age Z score, non-intake of 'other micronutrients' and malarial non-hyperendemic region were significant predictors of greater Hb response and heterogeneity. Thirteen trials were included in the review comparing Fe and micronutrient supplementation with Fe alone. The pooled estimate for change in Hb with Fe and micronutrient supplementation (weighted mean difference) was 0.14 g/dl (95 % CI 0.00, 0.28, P = 0.04). None of the variables were found to be significant predictors of Hb response.

CONCLUSIONS

Synthesized evidence indicates that addition of multiple micronutrients to Fe supplementation may only marginally improve Hb response compared with Fe supplementation alone. However, addition of 'other micronutrients' may have a negative effect. Routine addition of unselected multiple micronutrients to Fe therefore appears unjustified for nutritional anaemia control programmes.

Effect of multimicronutrient supplementation on gestational length and birth size: a randomized, placebo-controlled, double-blind effectiveness trial in Zimbabwe

BACKGROUND

Multiple micronutrient deficiencies may contribute to low birth weight, which is a major global determinant of mortality.

OBJECTIVE

We assessed the effect of prenatal multimicronutrient supplementation on gestational length and birth size.

DESIGN

We conducted a randomized, placebo-controlled, double-blind effectiveness trial among antenatal care attendees in Harare, Zimbabwe. Pregnant women (22-35 wk of gestation) were randomly allocated to receive a multimicronutrient or placebo supplement daily until delivery. Supplementation with iron and folic acid was part of antenatal care.

RESULTS

Of 1669 women, birth data were available from 1106 (66%), of whom 360 (33%) had HIV infection. The mean gestational length was 39.1 wk, and 16.6% of the women had a gestational length < 37 wk. The mean birth weight was 3030 g, and 10.5% of the infants had a birth weight < 2500 g. Multimicronutrient supplementation was associated with tendencies for increased gestational length (0.3 wk; 95% CI: -0.04, 0.6 wk; P = 0.06), birth weight (49 g; -6, 104 g; P = 0.08), and head circumference (0.2 cm; -0.02, 0.4 cm; P = 0.07) but was not associated with low birth weight (birth weight < 2500 g) (relative risk: 0.84; 0.59, 1.18; P = 0.31). The effect of multimicronutrient supplementation on birth weight was not significantly different between HIV-uninfected (26 g; -38, 91 g) and HIV-infected (101 g; -3, 205 g) subjects (interaction, P > 0.10).

CONCLUSION

Antenatal multimicronutrient supplementation may be one strategy to increase birth size.

The role of zinc in the growth and development of children

This review concerns the importance of zinc in growth, development, and cognitive function in children and the deleterious consequences of its deficiency on children's health. Possible strategies to overcome zinc deficiency and the results of some supplementation trials are discussed.

Can supplements help meet the micronutrient needs of the developing world?

Supplementation has many potential advantages over fortification and dietary approaches for improving micronutrient intake. Pregnant and lactating women and infants are most likely to benefit from supplementation. Recent experience with vitamin A supplementation in young children has proved to be remarkably successful. Demonstrated efficacy of vitamin A supplements for improved child survival in many settings and a technical consensus on how to implement interventions were major factors in achieving this success. Bilateral and UN agencies worked together so that in 1999 80 % of children under 5 years of age in the least-developed countries received a vitamin A capsule in the last 6 months. At least one million child lives saved were associated with the increase in coverage in the last 2 years of the 1990s. Experience with Fe-folate supplements has not been as successful. Whilst a technical consensus has been reached on how to implement programmes to control Fe deficiency, the lack of convincing evidence of efficacy of Fe-folate supplements in terms of maternal and child survival outcomes has undoubtedly contributed to the limited pursuit of effective action. A new multiple micronutrient supplement for use amongst women of reproductive age in developing countries has been formulated. UNICEF is employing the supplement in programmes aimed at helping to prevent low birth weight. The new supplement is likely to be more efficacious than Fe-folate supplements for both maternal and child survival and development outcomes. Successful completion of rigorous efficacy trials will be critical for creating the political support needed to achieve universal coverage.

Nutrition and maternal morbidity and mortality

Nearly 600 000 women die every year from pregnancy related conditions and the maternal mortality rates (MMR = deaths per 100 000 live births) in developing countries may be as high as 1000 compared with less than ten in industrialised countries. In the light of the striking impact of deficiencies of micronutrients such as vitamin A and zinc on immune function, morbidity and mortality in children it seems reasonable to suggest that such deficiencies might play a contributing role in the high rates of morbidity and mortality in mothers. Hitherto, there has been rather little published on the contribution of malnutrition to maternal morbidity or mortality but recent results of micronutrient supplementation show a major effect of vitamin A or beta carotene supplementation on maternal mortality in Nepal and an impressive effect of a multiple micronutrient mixture on pregnancy outcome in Tanzania. There is now data showing that subclinical mastitis, a potential risk factor for mother to child transmission of HIV by increasing levels of virus in breast milk, is influenced by maternal diet in Tanzania and feeding patterns in South Africa. Considering the massive tragedy of maternal mortality the recent data provides opportunities for new, innovative nutritional interventions for the reduction of the global burden of maternal morbidity and mortality.

Iodine deficiency in the world: where do we stand at the turn of the century?

Iodine deficiency is the leading cause of preventable mental retardation. Universal salt iodization (USI), calling for all salt used in agriculture, food processing, catering and household to be iodized, is the agreed strategy for achieving iodine sufficiency. This article reviews published information on programs for the sustainable elimination of the iodine deficiency disorders and reports new data on monitoring and impact of salt iodization programs at the population level. Currently, 68% of households from areas of the world with previous iodine deficiency have access to iodized salt, compared to less than 10% a decade ago. This great achievement, a public health success unprecedented in the field of noncommunicable diseases, must be better recognized by the health sector, including thyroidologists. On the other hand, the managers and sponsors of programs of iodized salt must appreciate the continuing need for greatly improved monitoring and quality control. For example, partnership evaluation of iodine nutrition using the ThyroMobil model in 35,223 schoolchildren at 378 sites of 28 countries has shown that many previously iodine deficient parts of the world now have median urinary iodine concentrations well above 300 microg/L, which is excessive and carries the risk of adverse health consequences. The elimination of iodine deficiency is within reach but major additional efforts are required to cover the whole population at risk and to ensure quality control and sustainability.

Micronutrient and iron supplementation and effective antimalarial treatment synergistically improve childhood anaemia

The control of childhood anaemia in malaria holoendemic areas is a major public health challenge for which an optimal strategy remains to be determined. Malaria prevention may compromise the development of partial immunity. Regular micronutrient supplementation has been suggested as an alternative but its effectiveness remains unsettled. We therefore conducted a randomised placebo-controlled intervention trial with 207 Tanzanian children aged 5 months to 3 years on the efficacy of supervised supplementation of low-dose micronutrients including iron (Poly Vi-Sol with iron) three times per week, with an average attendance of >/= 90%. The mean haemoglobin (Hb) level increased by 8 g/l more in children on supplement (95% CI 3-12) during the 5-month study. All age groups benefited from the intervention including severely anaemic subjects. The mean erythrocyte cell volume (MCV) increased but Hb in children >/= 24 months improved independently of MCV and no relation was found with hookworm infection. The data therefore suggest that micronutrients other than iron also contributed to Hb improvement. In the supplement group of children who had received sulfadoxine-pyrimethamine (SP) treatment, the mean Hb level increased synergistically by 22 g/l (95% CI 13-30) compared to 7 g/l (95% CI 3-10) in those without such treatment. Supplementation did not affect malaria incidence. In conclusion, micronutrient supplementation improves childhood anaemia in malaria holoendemic areas and this effect is synergistically enhanced by temporary clearance of parasitaemia.

Micronutrient malnutrition: policies and programs for control and their implications

Global progress in social and economic development is occurring, although slowly, in the most needy parts of the nonindustrialized world, where nutritional deficiencies, including micronutrients, remain significant public health problems. Until empowering benefits accrue from development spin-offs, policy guidance for purposeful public health actions can help reduce the unconscionable toll on health and quality of life from micronutrient malnutrition and can interrupt its intergenerational debilitating effects on national development. Narrowly focused control programs including homestead production, plant breeding, fortification, and supplementation are in effect, but in general, they have not been holistically planned and integrated into overall development programs. Such integration is needed to ensure sustainability into the next century. A new paradigm is needed, including a new way of thinking by nutrition scientists and program implementers that includes partnerships with the poor in all aspects of program planning and implementation.

Risks of iodine-induced hyperthyroidism after correction of iodine deficiency by iodized salt

Biochemical signs of hyperthyroidism, or even overt and possibly lethal clinical hyperthyroidism were reported in 2 severely iodine-deficient African countries (Zimbabwe and Democratic Republic of Congo, RDC) soon after the introduction of iodized salt. The 2 countries had access to iodized salt produced in Botswana, as well as 5 other countries in the region, namely Cameroon, Nigeria, Kenya, Tanzania, and Zambia. Therefore, a multicenter study was conducted in these 7 countries to evaluate whether the occurrence of iodine-induced hyperthyroidism (IIH) after the introduction of iodized salt was a general phenomenon or corresponded to specific local situations in the 2 affected countries. Two or 3 areas with a past history of severe iodine deficiency that had recently been supplemented with iodized salt were selected in each of the 7 countries. The prevalence of goiter was determined in 4423 schoolchildren in these areas and the concentration of urinary iodine in 2258. Salt factories and health structures were visited for the evaluation of the quality of iodized salt and the possible occurrence of IIH. The study showed that iodine deficiency had been eliminated in all areas investigated, and that the prevalence of goiter had markedly decreased since the introduction of iodized salt. This is a remarkable achievement in terms of public health. However, some areas were now exposed to iodine excess due mostly to a poor monitoring of the quality of the iodized salt and of the iodine intake of the population. In these areas or countries, IIH occurred only when the introduction of iodized salt had been of recent onset (<2 years), namely in Zimbabwe and RDC. In conclusion, the risk of IIH after correction of iodine deficiency is closely related to a recent excessive increment of iodine supply.