RECENT PUBLICATION: MULTIPLE PRE-ANALYTIC VARIABLES AFFECT ZINC ASSESSMENT

The choices of supplies and procedures, i.e. the pre-analytic variables, that researchers make when measuring zinc concentration from blood samples can be critical for the accuracy and precision of the study.

Blood draw site, blood matrix, blood collection tube type, processing time, and holding temperature were all found to have small but significant impacts on zinc assessment taken in a group of healthy adults with most other technical variables controlled. For similar reasons, caution is warranted when comparing studies that use different procedural methods to measure zinc concentration in plasma or serum. Read more in this new publication in PLOS One.  

Photo credit: World Bank photo collection on Flickr

Upcoming webinar: Large-scale food fortification – an underutilized strategy for addressing zinc deficiency

Date: December 5

Time: 12 noon EDT | 5 pm GMT | 8 pm EAT

Over the past four years, IZiNCG’s Zinc Fortification Task Force has generated evidence and advocacy materials on large-scale food fortification (LSFF) with zinc. This webinar will showcase work undertaken by the Task Force, and discuss country experiences and actions.

Zinc is an essential nutrient for immune function, child health and development, and reproductive health. Based on available data, zinc deficiency is estimated to be a public health problem in 40 countries, concentrated primarily in sub-Saharan Africa and South Asia

LSFF is one of the most scalable, sustainable, and cost-effective tools available to reduce micronutrient deficiencies and improve nutrition worldwide. Recent publications have demonstrated that LSFF with zinc is effective, safe and cost-effective. However, at present, LSFF with zinc is an underutilized strategy for addressing zinc deficiency in countries where zinc deficiency is a public health problem.

Join us for presentations on the global state of zinc deficiency, the evidence behind zinc fortification as a strategy to address zinc deficiency, the current zinc fortification landscape, the potential impact of scaling up food fortification with zinc, and priority actions countries can take. The webinar will conclude with a panel discussion about country experiences. Register here.

Moderator
Dr Mduduzi Mbuya | Director, Knowledge Leadership, Global Alliance for Improved Nutrition

Speakers and panelists
Dr Christine McDonald | Director of IZiNCG and Associate Professor, University of California, San Francisco
Dr Mari Skar Manger | Deputy Director of IZiNCG, University of California, San Francisco
Dr Ryan Wessells | Associate Project Scientist, University of California, Davis
Mr Frederick Grant | Senior Program Officer, Nutrition, Bill & Melinda Gates Foundation Ethiopia
Dr Ndèye Fatou Ndiaye | Coordinator of Senegalese Committee for Food Fortification (COSFAM), Ministry of Industry and Industrial Development, Government of Senegal
Mr Alex Marco Ongla Ndjebayi | Project Coordinator, Helen Keller International Cameroon

This webinar is kindly supported by the International Zinc Association and kindly hosted by the Global Alliance for Improved Nutrition. Everyone who registers will receive a recording of the webinar.

New video about zinc fortification!

IZiNCG is pleased to share our new animated short produced in collaboration with the International Zinc Association. The video is only 2 minutes long – enjoy!

Fortification as a strategy to reduce zinc deficiency.

Quick facts about zinc fortification

Zinc fortification is not a silver bullet for eliminating zinc deficiency but has the potential to improve dietary zinc intake and related health outcomes at the population level. In our latest resource, we share key facts about zinc deficiency globally and the potential impact of fortifying staple foods with zinc, alongside other micronutrients.

• More than one billion people are at risk of inadequate zinc intake.

• Large-scale food fortification (LSFF) with zinc can halve the proportion at risk of inadequate zinc intake globally.

• LSFF with zinc is effective, safe and cost-effective.

• LSFF with zinc can serve as a key nutrition strategy in countries where zinc deficiency is a public health problem.

Click here for further IZiNCG resources about zinc fortification.

New estimate of the global prevalence of hidden hunger - what does it say about zinc?

Newly published research indicates that 1 in 2 children under the age of five and 2 in 3 women aged 15-49 are affected by micronutrient deficiencies globally.  This is equivalent to 372 million preschool children and 1.2 billion women. With these two population groups making up only one-third of the population worldwide, the total number of affected people is likely to be far larger once school-age children, adolescents, men and older adults are included in the estimate.

For over three decades it has been stated that micronutrients affect 2 billion people globally. However, this estimate has been based on the number of people with anemia, which is not equivalent to deficiencies in iron, zinc, folate, vitamin A, and other essential micronutrients.  A global prevalence estimate based on individual-level biomarker data has been desperately needed.

With funding from USAID, the Global Micronutrient Deficiencies Research Group led by the Global Alliance for Improved Nutrition (GAIN) pooled and re-analyzed individual-level biomarker data on micronutrient status from nationally representative, population-based surveys to estimate the prevalence and number of preschool children (6–59 months) and non-pregnant women of reproductive age (15–49 years) with one or more micronutrient deficiencies, globally and regionally.

The analysis included 24 datasets from nationally representative surveys in 22 countries. Zinc was selected as one of three core micronutrients together with iron and vitamin A for preschool children, and iron and folate for women. Data on plasma/serum zinc concentrations in PSC and WRA were available in 16 and 15 datasets, respectively. Among preschool children, the prevalence of zinc deficiency was ≥20% (the cutoff used to indicate a public health problem) in 12 datasets, and 10–19% in 4 datasets.  Among women, the prevalence of zinc deficiency was ≥20% in the 13 datasets from LMICs, 14% in United States and 10% in United Kingdom.  The countries with the highest prevalence of zinc deficiency (>50%) among both population groups were Cambodia, Cameroon, Malawi and Vietnam, as well as Ecuador for women.

The dearth of micronutrient biomarker data has been well-recognized and several recommendations to address this problem have been published. Along with the authors of these new global estimates, IZiNCG hopes the results of this analysis highlight the need for more and improved data on micronutrient status, increased funding for programs to implement and scale-up interventions to prevent micronutrient deficiencies, and improved monitoring and evaluation of such programs. 

Photo credit: World Bank photo collection

Is there a new biomarker on the block when it comes to measuring zinc status? …Yes & No!

Julie M. Long of the University of Colorado, Denver discusses the exchangeable zinc pool (EZP) as a biomarker of zinc status and reviews the findings from a recently published sub-study of the Zinc in Powders Trial.

While a lot is known about dietary zinc requirements through the lifecycle and the necessity of this trace mineral for optimal growth, development, and immune function, identification of a ‘gold standard’ biomarker for zinc status remains elusive (1). Currently, serum or plasma zinc status or proxy indicators like dietary zinc intake or stunting rates, are used to estimate zinc status, but each has its limitations.

Small, observational studies suggest that the EZP may be a way to measure zinc status. The EZP is defined as the size of the combined pools, such as the liver, in the body that readily exchange with zinc in the plasma within 2–3 days. This rapidly exchanging zinc is estimated to include approximately 10% of total body zinc and is thought to reflect metabolically active zinc (2). Additionally, adult and pediatric studies suggest that EZP correlates well with dietary zinc intake and zinc absorption, and unlike serum or plasma zinc, EZP size may not decrease when systemic inflammation is present (3-5).

Recently a sub-study of the Zinc in Powders Trial (6) allowed researchers to test the usefulness of EZP as a marker of zinc status via a double blinded randomized controlled trial of zinc supplementation. The sub-study prospectively compared the change in EZP from study start to finish in children who were preventively supplemented with 10 mg of zinc for 6 months as part of a multiple micronutrient powder (MNP) consumed with food or as a zinc dispersible tablet versus a placebo powder.

The major findings of this study included:

·       EZP increased for children who were given zinc supplements compared to no change for children that consumed a placebo powder

·       Children who consumed the zinc dispersible tablet had the greatest increase in EZP, double the increase of children in the MNP group

·       EZP of children experiencing systemic inflammation at baseline did not differ from EZP of children without inflammation

While these results are promising, the limitations of EZP as a biomarker include the requirement for use of stable isotope methodology, including careful urine collections and specialized analyses. Thus, it is less “field friendly” than serum zinc and presently may best be viewed as a useful addition to the zinc toolbox.

The implications of this study’s findings indicated that EZP was responsive to changes in zinc intake and was most responsive to the consumption of the more bioavailable zinc in a dispersible tablet. Additionally, unlike serum or plasma zinc, EZP appears to be resistant to changes when inflammation is present, suggesting it has potential to accurately and reliably measure zinc status!

References:

1.     King, J.C.; Brown, K.H.; Gibson, R.S.; Krebs, N.F.; Lowe, N.M.; Siekmann, J.H.; Raiten, D.J. Biomarkers of Nutrition for Development (BOND)-zinc review. J. Nutr. 2016, 146, 858S–885S.

2.     Miller, L.V.; Hambidge, K.M.; Naake, V.L.; Hong, Z.; Westcott, J.L.; Fennessey, P.V. Size of the zinc pools that exchange rapidly with plasma zinc in humans: Alternative techniques for measuring and relation to dietary zinc intake. J. Nutr. 1994, 124, 268–276.

3.     Krebs, N.F.; Westcott, J.E.; Culbertson, D.L.; Sian, L.; Miller, L.V.; Hambidge, K.M. Comparison of complementary feeding strategies to meet zinc requirements of older breastfed infants. Am. J. Clin. Nutr. 2012, 96, 30–35.

4.     Miller, L.; Long, J.; Mondal, P.; Westcott, J.; Islam, M.M.; Ahmed, M.; Ahmed, T.; Krebs, N. Exchangeable Zinc Pool (EZP) size in Bangladeshi toddlers at risk of environmental enteric dysfunction (EED) is not influenced by inflammation (OR07-03-19). Curr. Dev. Nutr. 2019, 3 (Suppl. 1), nzz034.OR07-03-19.

5.     Miller, L.V.; Hambidge, K.M.; King, J.C.; Westcott, J.E.; Krebs, N.F. Predictors of the size of the exchangeable zinc pool differ between children and adults. J. Nutr. 2017, 147, 187–194.

6.     Islam, M.M.; Black R.E.; Krebs N.F.; Westcott J.; Long J.; Islam K.M.; Peerson J.M.; Sthity R.A.; Khandaker A.M.; Hasan M.; El Arifeen S.; Ahmed T.; King J.C.; McDonald C.M. Different doses, forms, and frequencies of zinc supplementation for the prevention of diarrhea and promotion of linear growth among young Bangladeshi children: a six-arm, randomized, community-based efficacy trial. J Nutr. 2022, 152(5), 1306-1315.

Photo credit: World Bank Photo Collection

The Zinc in Powders Trial: more than a "null finding"

The findings from IZiNCG’s Zinc in Powders Trial (ZiPT), conducted in collaboration with icddr,b, are published! ZiPT was a randomized, partially double-blind, controlled, community-based efficacy trial involving 2886 young children in Dhaka, Bangladesh. Children 9-11 months old were randomly assigned to one of six different intervention groups: a standard micronutrient powder (MNP) containing 4.1 mg zinc and 10 mg iron, daily; a high-zinc (10 mg), low-iron (6 mg) MNP, daily; high-zinc low-iron and high zinc, no-iron MNPs on alternating days; dispersible zinc tablet (10 mg), daily; dispersible zinc tablet (10 mg), daily for 2 weeks at enrollment and 12 weeks; and placebo powder, daily. The interventions were provided for 24 weeks, and intensive twice weekly morbidity surveillance occurred over the intervention period.  To summarize the key findings, there were no differences in the incidence or prevalence of diarrhea across intervention groups, and only the high-zinc, low-iron MNP group had a slightly smaller decline in length-for-age z-score compared with the placebo powder group, prompting a corresponding editorial to ask “has zinc lost its shine?”.

ZiPT was designed to narrow a host of evidence gaps around preventive zinc supplementation and MNP formulations. Despite the consistency of evidence for preventive zinc supplementation in reducing the incidence of diarrhea and eliciting small but significant increases in height, no formal recommendations for preventive zinc supplementation exist. MNP programs are reaching over 10 million children globally, and the standard MNP formulation includes 15 micronutrients, including zinc. Hence MNPs are an attractive vehicle for delivery of preventive zinc and other essential vitamins and minerals to young children. At the time ZiPT was designed, there was some limited evidence that MNPs may be associated with an increase in diarrheal incidence and it was hypothesized that the iron content of the MNPs may be a contributing factor. Furthermore, the available evidence indicated that MNPs had minimal effects on child growth, and evidence was emerging that the amount of zinc in the standard MNP formulation (4.1mg) was probably insufficient in settings with a high prevalence of environmental enteric dysfunction (EED). Lastly, the effect of zinc-containing MNPs on serum zinc concentrations was inconclusive.

The findings from ZiPT underscore the reality that micronutrient supplementation is not a “silver bullet” to improving functional child health outcomes, and that several other factors such as EED, premature introduction of complementary food of poor nutritional quality and intrauterine growth restriction may have had a more substantial impact on diarrhea and linear growth in this study population. However, there are several important take-home messages from the ZiPT findings that deserve highlighting.

First, it was reassuring that MNPs did not cause a higher incidence or prevalence of diarrhea, as previously observed in some trials.

Second, the lack of an effect of stand-alone preventive zinc supplementation on rates of diarrhea was somewhat surprising and contrasts much of the literature, particularly given the high burden of diarrheal disease and high compliance to the study interventions in this population. However, a recent trial in Laos among children aged 6–23 months similarly found that neither preventive zinc nor MNPs significantly reduced the incidence or duration of diarrhea. It is possible that therapeutic zinc, received by all children according to WHO guidelines when experiencing a diarrhea episode, may have helped prevent future episodes of diarrhea among children in all groups. It is also possible that the higher doses of therapeutic zinc supplementation may have local, pharmacologic effects on the gastrointestinal tract, thereby reducing the risk of diarrhea in contrast to lower-dose preventive zinc supplementation.

Third, both the daily dispersible zinc tablet and the high-zinc, low-iron MNP formulation, which provided 10mg of zinc, did a remarkable job at improving serum zinc concentrations:  the prevalence of low serum zinc concentrations fell from 48% to 6% and 29% to 12%, respectively. These marked improvements in zinc status in the absence of a response in functional outcomes raise the possibility that the 24-wk duration of ZiPT may have been insufficient to elicit a response in linear growth. However, the modest improvements in linear growth among children in the daily high-zinc, low-iron MNP group compared with the placebo powder group suggests that the zinc content in the standard MNP formulation may need to be increased, at least in populations at risk for EED. 

Where to next? Should MNPs be recommended as an intervention to improve zinc status despite the lack of impact on diarrhea and linear growth? Given the need for targeted interventions to improve zinc intakes of children 6-23 months of age layered on top of population-based strategies such as large-scale food fortification, MNPs remain an attractive vehicle with potential benefits beyond simply delivering additional zinc and other micronutrients. Furthermore, there is no “one size fits all” approach. Ideally, micronutrient delivery approaches need to be designed and tailored according to local dietary practices, micronutrient deficiency prevalence data, and the existence of other interventions. We will be sharing more findings from ZiPT soon. Stay tuned for a deep dive.

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The ZiPT trial is a collaboration between icddr,b, IZiNCG, the University of California, San Francisco, Johns Hopkins University, and the University of Colorado. Funding for the trial was provided from the Bill & Melinda Gates Foundation to IZiNCG.

Zinc fortification country briefs: Honduras, Burkina Faso and Senegal

Zinc fortification reduces the prevalence of zinc deficiency and may improve associated health outcomes. Which actions should governments and supporting partners take to address zinc deficiency through fortification?

A July 2021 analysis conducted by IZiNCG identified 35 countries where zinc deficiency is a national public health issue. Honduras, Burkina Faso and Senegal are among these countries, but their existing large-scale food fortification programs do not include zinc. Adding zinc to these existing mandatory fortification programs would be a relatively low-cost, high-impact intervention to reduce their national prevalence of zinc deficiency. 

These country briefs provide the rationale for zinc fortification, describe where the selected countries stand with regards to zinc deficiency and food fortification, and outline key actions government and supporting partners can take to address zinc deficiency through zinc fortification.

Honduras

Burkina Faso

Senegal

Joint statement on the power of micronutrients

Call to Action on Mighty Nutrients! Improving diets with micronutrients is a powerful investment for people, planet and prosperity.

Ahead of the Nutrition for Growth Summit, IZiNCG joins the the Micronutrient Forum, UNICEF, GAIN, HarvestPlus and the Iodine Global Network to urge donors, governments, and private sector leaders to rapidly scale up micronutrient interventions, which offer an opportunity to transform food and health systems, save and improve lives and achieve the 2030 Agenda for Sustainable Development.

Sign the Call to Action here.

Sign up for the Nutrition for Growth official side event Mighty Nutrients here.

The global financing facility endorses the importance of zinc in diarrhea treatment

IZiNCG joins the ORS/zinc co-pack alliance (ORSZCA) in celebrating the clarification made last week by the Global Financing Facility to their Reclaim the Gains campaign to mention zinc alongside oral rehydration solution (ORS) treatment.

Reclaim the Gains is a significant global initiative aimed at improving access to diarrhea treatment. We are pleased that the goals of the campaign are now in line with WHO and UNICEF recommendations of low osmolarity ORS and zinc sulphate tablets for 10–14 days.

Poor coverage of zinc and ORS is a major reason why more than 500,000 children under five are still dying from diarrhea each year. Reclaim the Gains aims to provide 458 million additional children with ORS and zinc treatment for diarrhea by 2025. We applaud this effort and commitment!

Call to Action: Addressing zinc deficiency through zinc fortification

IZiNCG’s Zinc Fortification Task Force is pleased to share this Call to Action to close the global zinc fortification gap.

Large-scale food fortification (LSFF) is one of the most effective interventions for improving micronutrient status. We have recently published a systematic review and meta-analysis which showed that zinc fortification can reduce the prevalence of zinc deficiency.

This advocacy brief presents the LSFF situation in countries where zinc deficiency is a public health issue, and outlines priority actions these countries should take pertaining to food fortification. Among these countries are 11 countries where zinc fortification can have a significant and immediate impact because a mandatory fortification program already exists, but it does not include zinc.

The members of our Zinc Fortification Task Force represent the Food Fortification Initiative, the Global Alliance for Improved Nutrition, Nutrition International, and the IZiNCG Steering Committee.

Zinc fortification reduces the prevalence of zinc deficiency

Two years in the making, IZiNCG’s Zinc Fortification Task Force is pleased to share the publication Effects of Foods Fortified with Zinc, Alone or Cofortified with Multiple Micronutrients, on Health and Functional Outcomes: A Systematic Review and Meta-Analysis.

Why zinc fortification 

Postharvest food fortification is considered a highly cost-effective intervention to improve dietary intake of micronutrients. As such, many countries with a high burden of zinc deficiency could benefit from including zinc in their mandatory fortification standard. 

Why we conducted this review

IZiNCG last reviewed the evidence on zinc fortification in 2009 and concluded that additional information was needed on the efficacy and effectiveness of fortification programs, as only a few studies had found a positive impact on plasma/serum zinc concentrations or functional indicators of zinc status. Although a Cochrane review was conducted in 2016, it was restricted to studies with comparison groups that allowed the independent effect of zinc to be isolated.  Posing this condition meant excluding a large body of literature relevant to the “real world” context of large-scale food fortification yet to be synthesized for zinc-related outcomes.

What we found

Our systematic review synthesizes data from 59 studies which assessed biochemical and health outcomes after the provision of a zinc-fortified food or beverage. Fortification vehicles were primarily cereal grains and products, followed by beverages and condiments. The median dose of zinc provided by fortification across studies was 4.4 mg per day, study durations varied from 1 month to 3 years, and 71% of studies were conducted in low- or lower-middle-income countries.

We found that food fortification with zinc, given alone or with other micronutrients, increased plasma/serum zinc concentrations, with a corresponding 24% and 55% decrease in the prevalence of zinc deficiency in efficacy and effectiveness studies, respectively. We also found that fortification with zinc and other micronutrients may increase child weight, reduce episodes of diarrhea and fever and improve cognitive function. However, fewer studies evaluated these latter outcomes and the effects cannot be solely attributed to zinc. We found no adverse outcomes after food fortification with zinc.

Why this matters

Findings from this systematic review show that fortification with zinc, alone or together with other micronutrients, is an efficacious and effective strategy for reducing the prevalence of zinc deficiency in low- and middle-income countries. Globally, nearly 30 countries have mandated the inclusion of zinc in their wheat flour, maize, and/or rice fortification programs. Yet, preliminary analyses show that another 30 countries could benefit from either including zinc in an existing fortification program, or establishing a new fortification program that includes zinc. We hope these findings will encourage more countries whose populations could benefit from zinc fortification to include zinc as a fortificant in an existing or new program.  

Zinc Fortification Task Force

The IZiNCG Fortification Task Force is made up of representatives from the IZiNCG Steering Committee, the Food Fortification Initiative, the Global Alliance for Improved Nutrition and Nutrition International.

Enablers and barriers of zinc fortification; experience from 10 low- and middle-income countries

The first publication from IZiNCG’s Zinc Fortification Task Force, Enablers and Barriers of Zinc Fortification; Experience from 10 Low- and Middle-Income Countries with Mandatory Large-Scale Food Fortification, is now available in Nutrients.

Food fortification presents an opportunity for enhancing zinc intakes. Despite data suggesting zinc deficiency as being a potential public health problem, only 29 out of 72 low- and middle-income countries with mandatory fortification programs for cereal grains include zinc as a mandatory fortificant.

To guide policy decisions, we investigated the factors enabling and impeding the inclusion of zinc as a fortificant by conducting a series of in-depth interviews with key informants from 10 countries. We learnt that the decision to include zinc was strongly influenced by guidance from international development partners. Enabling factors included the assessment of zinc deficiency, mandatory regional food fortification standards which included zinc, the World Health Organization (WHO) guidelines for zinc fortification, and the low cost of the zinc compound commonly used. Barriers included the absence of zinc from regional fortification standards, limited available data on the efficacy and effectiveness of zinc fortification, and the absence of national objectives related to the prevention of zinc deficiency.

Systematic review coming soon

More evidence about the impact of zinc fortification is available now compared with when many of the countries interviewed the planning of their zinc fortification programs. We have conducted a review of efficacy and effectiveness studies to ascertain the effect of zinc fortification - alone or with multiple micronutrients - on a range of health outcomes. The review has been accepted for publication in Advances of Nutrition.

IZiNCG’s Zinc Fortification Task Force

The objective of Phase 1 of the Task Force has been to assess the efficacy and effectiveness of zinc fortification interventions, and to identify opportunities to enhance impact. We are now moving into Phase 2 - watch this space. Our members represent the Food Fortification Initiative, the Global Alliance for Improved Nutrition, Nutrition International, and the Global Fortification Data Exchange.

Read more about strategies for promoting zinc nutrition here.

Principles of Nutritional Assessment, third edition

Dr. Rosalind Gibson’s Principles of Nutritional Assessment is known by many as “the nutritional assessment bible”. This comprehensive resource is now under revision and revised chapters are being made freely available on https://nutritionalassessment.org.

So far seven chapters are available, including the chapter on zinc! The other available chapters are on the topics of food consumption of individuals, nutrient reference values, vitamin D, calcium, copper, and selenium. The chapters have been radically revised with additional new content, diagrams and references.

IZiNCG’s page on assessment of zinc status has been updated with references to this new online resource.

Dr. Gibson is an IZiNCG Steering Committee Emerita and a present IZiNCG collaborator. We are so grateful for Ros’s effort to produce a third edition of “the book” and for making it accessible to anyone with an internet connection.

The India CNNS: A monumental survey identifying those at most risk of zinc deficiency

India’s 2016-2018 Comprehensive National Nutrition Survey (CNNS) is a truly admirable undertaking, as it is one of the largest micronutrient surveys ever conducted. This month, full results of the serum zinc status of children and adolescents were published in the American Journal of Clinical Nutrition with an accompanying editorial. 

Serum zinc concentrations (SZC) were assessed in more than 28,000 pre-schoolers, school aged children, and adolescents. Nationally, the prevalence of low SZC was 31.1% among adolescents, 15.8% among school-aged children and 17.4% among preschool children. State-level prevalence estimates ranged from 2.4% in Mizoram to 38.8% in Himachal Pradesh, using data for pre-school children as an example.  By providing much-needed data on zinc status at the national- and state- levels, the CNNS highlights the importance of biochemical data on micronutrient status to guide the targeting of interventions to the most vulnerable populations.  

It is helpful to start with what these prevalence estimates actually mean. India is the second most populous country in the world. While the prevalence of low SZC among children and adolescents may be lower in comparison to most of the 26 other low- and middle-income countries with available data on SZC, the CNNS findings indicate that approximately 38 million Indian children and 71 million Indian adolescents have an elevated risk of zinc deficiency. Those are staggering numbers.

It is important for individual governments to decide upon criteria to define national public health problems given a variety of contextual factors.  However, IZiNCG considers the risk of zinc deficiency to be of public health concern when the prevalence of low SZC is higher than 20%. This means that, at 31.1%, the prevalence of low SZC among adolescents calls for further investigation and action, particularly considering the intergenerational cycle of undernutrition and the fact that many girls who are zinc-deficient in adolescence will likely continue to be zinc-deficient during pregnancy in the absence of any intervention.   

Although the national prevalence estimates for zinc deficiency among pre-school and school-aged children were below 20%, state-level analyses revealed that the prevalence of zinc deficiency among preschool and school-aged children exceeded the 20% threshold in 10 out of 30 and 8 out of 30 states, respectively.  

Drilling down further, the results show that low SZC was more common among preschool children with rural residence, mothers with lower levels of education, and poorer household socioeconomic status and sanitation facilities. These findings identify vulnerable subgroups that should be prioritized to receive zinc interventions through existing platforms such as the Public Distribution System, Mid-day Meal program, and the Integrated Child Development Services, as well as new delivery channels.

An excellent review of the survey’s methods can be found in the editorial by Brown et al. As these authors note, no external quality assessments were reported for the laboratory assessment of SZC, which highlights the need for an easily accessible, global laboratory standardization program for SZC analysis.

In summary, the government of India is to be commended for undertaking such a monumental survey and generating the data needed to guide future interventions. The next challenge is to develop programs to address zinc and other micronutrient deficiencies in populations most in need.

Six take-aways for zinc in the Lancet Series on Maternal and Child Undernutrition Progress

Thirteen years since the first landmark Lancet Series on Maternal and Child Undernutrition, we celebrate the new series reporting on progress and new evidence, and join the call to action. Here are six take-away messages for zinc.

1) Zinc deficiency is highly prevalent in the few countries with biochemical data available. 

Previously summarised by Gupta and colleagues in 2020, among 25 countries for which national data on plasma/serum zinc concentrations were available, 23 had a zinc deficiency prevalence of 20% or higher for at least one physiological group.

The Series authors point out that surveys in sub-Saharan Africa have found that more than half of the children surveyed had serum zinc concentrations indicative of deficiency. This was also the case in some countries in Asia, such as Bangladesh, Cambodia and Vietnam. And more importantly, more data on zinc status are urgently needed (see 2!). 

2) A vast data gap exists for zinc and other micronutrient deficiencies. 

The Series authors point out the big data gap for biomarkers of micronutrient status, particularly for women, in addition to data gaps on fetal growth, including birthweight and gestational age assessments. 

Obtaining more data is a priority because it will enable targeting of interventions, improved tracking of programme outcomes, and enhanced accountability. 

3) Reinforcing a focus on the first 1000 days for zinc interventions.

Women of reproductive age and children under 5 are priority populations for IZiNCG for a good reason. We concur with the Series authors that the cumulative benefit of evidence-based interventions across each life stage will produce the highest gains, and that “interventions and actions targeting this age window require renewed commitment, new insights from implementation research, and fast-tracked funding to increase coverage and improve quality of service delivery.” 

4) Preventive zinc supplementation - opportunities for action.

Preventive zinc supplementation remains on the Series list of recommended interventions in the category “moderate evidence for implementation”. The Series authors label the effect of preventive zinc supplementation on diarrhoea incidence as robust, and recommend exploration of preventive zinc supplementation in at-risk populations. 

Over the past 4 years, IZiNCG has explored the delivery of preventive zinc in the form of micronutrient powders (MNPs) with increased amounts of zinc in comparison with standard MNPs and dispersible zinc supplements.  We are also encouraged by the new evidence on the superiority of multiple micronutrient supplements (MMS) over iron-folic acid for pregnancy outcomes, as the existing UNIMMAP MMS formulation contains 15mg of zinc. In other words, zinc is already being delivered through several of the recommended evidence-based interventions to address maternal- and child undernutrition. IZiNCG will continue to conduct implementation research to identify optimal delivery models for preventive zinc interventions. 

5) Delivering preventive zinc through food fortification.

Large-scale food fortification (LSFF) as a strategy for preventing micronutrient deficiencies is backed by “strong evidence for implementation” and is an opportunity for delivering zinc to whole populations at low cost. IZiNCG has been working on updating the evidence base for zinc fortification and to identify opportunities for enhancing the impact of LSFF when it comes to zinc. Watch this space.

6) Zinc saves lives but coverage of zinc for diarrhea treatment is low.

Therapeutic zinc supplementation for diarrhoea management remains a life-saving intervention with strong evidence for implementation. Since 2004, WHO has recommended zinc, together with oral rehydration salts, for treatment of diarrhoea, but coverage remains very low. Renewed efforts are required to improve coverage of therapeutic zinc supplementation and save more lives.

Figure 2, “Recommended evidence-based interventions to address malnutrition, according to strength of evidence“ in Keats EC, Das JK, Salam RA, Lassi ZS, Imdad A, Black RE, Bhutta ZA. Effective interventions to address maternal and child malnutrition: an update of the evidence. Lancet Child Adolesc Health. 2021 Mar 5:S2352-4642(20)30274-1.

Recent publication: Comparison of laboratory instrument types for analysis of plasma or serum zinc concentration

When standardized methods are used for the preparation and analysis of zinc concentrations in plasma and serum, each laboratory instrument type provides similar mean results and similar accuracy and precision. Read more in IZiNCG’s technical brief no. 12 and in this new publication in Biological Trace Element Research.

Although the prevalence of low plasma or serum zinc concentration (PZC) is associated with the prevalence of inadequate zinc intake, numerous other physiological and methodological factors may also influence PZC. IZiNCG Technical Briefs no. 2 and 6, and IZiNCG Practical Tips documents provide guidance on these factors. However, the potential effects of other analytical issues, such as the type of laboratory instrument used, have not been systematically evaluated. 

Three instrument types are commonly used for PZC analysis: atomic absorbance spectrometers (AAS), inductively-coupled plasma optical emission spectrometers (ICP-OES), and ICP mass spectrometers (ICP-MS).  IZiNCG designed a laboratory methods study to assess the accuracy and precision of these instruments for analyzing zinc concentrations in plasma and serum. Seven laboratories in four countries, including two low- to middle-income countries, using nine instruments (4 AAS, 1 ICP-OES, 4 ICP-MS), participated in the study.  All laboratories received a standard set of samples, materials and reagents, and reference methods for sample preparation and analysis. Read more here.

Updated: 31 August 2021

Inclusion of Micronutrient Biomarkers in National Surveys and Surveillance Systems: Barriers and Enablers

IZiNCG is pleased to share the report Inclusion of Micronutrient Biomarkers in National Surveys and Surveillance Systems: Barriers and Enablers. This work was conducted with the support of the Micronutrient Forum.

Including biomarkers of micronutrient status in existing or planned national surveys or surveillance systems would dramatically improve capacity to promote, design, monitor and evaluate micronutrient policies and programs. Ultimately, investing in better data would yield healthier populations, safer programs and cost savings. 

Yet, the availability of nationally representative micronutrient biomarker data in low- and middle income countries (LMICs) is scarce. Taking plasma/serum zinc concentrations among pre-school children as an example, only 26 LMICs have published data.

“Micronutrient deficiencies are estimated to impact a significant number of people around the world, but there remains far too little information on micronutrient status and deficiencies. More essential information and surveillance need to be gathered to make substantial progress on global targets.” 

Global Nutrition Report 2018

The objectives of this study were to identify barriers to, and enablers of, the inclusion of micronutrient biomarkers in national surveys and surveillance systems. IZiNCG conducted a series of key informant interviews with in-country and external representatives from six countries where national-level data on micronutrient status had been collected in the past five years: Cambodia, Pakistan, Malawi, Uganda, Ghana and Uzbekistan.

The most important and frequently reported barrier to inclusion of a more comprehensive panel of micronutrient biomarkers was inadequate funding to cover the analysis cost for all micronutrients considered at the planning stage. Government support and commitment was stressed as the most important enabling factor by all key informants. For the findings in full, please read the report here.

What can be done to address the barriers identified in the report, and see more countries including micronutrient biomarkers in national surveys? This project is part of a wider collaborative effort led by the Micronutrient Forum aimed at increasing the availability and utilization of high-quality data on micronutrient status at the national/sub-national levels in LMICs. Read more in this recent publication.

Last updated: June 9, 2021

Holiday greetings & Newsletter No. 5

2020 has been a challenging year, but we are pleased to report progress on many IZiNCG activities in our Newsletter No. 5. We would like to take this opportunity to thank our collaborators for their endurance, persistence and good spirits - we couldn’t have made progress without you!

We would also like to thank everyone who visited our website for news and resources. IZiNCG aims to pool together the talents and experience of the world's leaders in zinc nutrition and become a global resource for the best science, strategic thinking, and policy recommendations to control zinc deficiency.

Our small group cannot achieve this mission without the help, collaboration and direction from our wider nutrition and health community. We would love to hear from you.

You can contact us on secretariat@izincg.org, or by using this contact form.

With kind regards,

Christine McDonald (Director) and Mari Manger (Deputy Director)

Let's connect at CONNECTED!

It’s finally time for Micronutrient Forum 2020 aka CONNECTED! IZiNCG’s symposium Advancing efforts to improve zinc nutrition globally will be available on demand.

We are grateful for the hard work our colleagues at the Micronutrient Forum have put into making this conference possible as a state-of-the-art virtual conference from November 9 -13. The program is available here.

IZiNCG’s symposium is available on demand under sponsored sessions. In this symposium, you can enjoy the following presentations:

• Introduction and overview of IZiNCG (Christine McDonald, University of California, San Francisco)

• Assessment of zinc status: Recent developments and opportunities for action (Kenneth Brown , University of California, Davis)

• Preventive zinc supplementation for young children: key findings from the Zinc in Powders Trial (Munirul Islam, icddr,b)

• Zinc interventions during pregnancy (Nancy Krebs, University of Colorado, Denver)

• Progress in the use of therapeutic zinc as part of diarrhea treatment (Felix Lam, Clinton Health Access Initiative)

• Concluding remarks (Christine McDonald, University of California San Francisco)

IZiNCG’s virtual booth is up and running and will be available throughout the conference. In this space, you can download resources, contact us with questions and request a video chat. We hope to “see” many of you there!