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Fortification Task Force

Zinc fortification reduces the prevalence of zinc deficiency

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

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.

Zinc Fortification Task Force initiates efforts to enhance the impact of zinc fortification interventions

Zinc Fortification Task Force initiates efforts to enhance the impact of zinc fortification interventions

Why a Zinc Fortification Task Force?

Fortification of staple foods and/or condiments with zinc appears to be a promising strategy for improving zinc status at the population level in low- and middle-income countries because of its relatively low cost and long-term sustainability. The motivation for establishing a Zinc Fortification Task Force is to progress IZiNCG’s position and recommendations related to zinc fortification, taking into account recent evidence, existing global guidelines, and the fact that mandatory zinc fortification is in place in more than 30 countries. The Task Force harnesses the perspectives of the Food Fortification Initiative, the Global Alliance for Improved Nutrition and Helen Keller International together with IZiNCG.

 

IZiNCG’s current stance on zinc fortification 

A review in IZiNCG’s 2009 Technical Document no. 2 summarised evidence showing that fortifying staple foods with zinc increases total daily zinc absorption, does not adversely affect the absorption of other minerals, is not associated with adverse effects and is a relatively low-cost intervention (1). Therefore, IZiNCG’s recommendation following this review was that countries should consider including zinc in mass and targeted fortification programs in populations at high risk of zinc deficiency. However, the review also pointed to the paucity of evidence on the efficacy and effectiveness of fortification programs, and that only a few studies had found a positive impact on plasma/serum zinc or functional indicators of zinc status.

Recent reviews

A 2016 Cochrane review of zinc fortification concluded the same: given the relatively small number of trials and participants, further investigation of the effects of zinc fortification was needed (2). However, the Cochrane review excluded many studies on the basis that zinc was not the only nutrient which differed between intervention and control groups, despite plasma/serum zinc being measured as an outcome. While such comparisons may be useful from an epidemiological perspective, they may not fully capture the real-world context.  For example, 34 countries have mandatory zinc fortification in place, with zinc being part of a premix with several other micronutrients. In a very recent review of large-scale food fortification on vitamin A, iodine, iron and folic acid status and health outcomes, this “real-world impact” was at the centre (3). However, this latter review excluded trials with less than 1000 participants, which would be too limiting in the case of available publications on zinc fortification.

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Planned work of the taskforce 

The overarching goal of the task force is to assess the efficacy and effectiveness of zinc fortification interventions, and to identify opportunities to enhance impact. The first activity is to produce an update to the previous zinc fortification systematic reviews, summarising the additional evidence now available on zinc fortification. In addition to determining the impact of zinc fortification on zinc-related biochemical and functional outcomes, the review will attempt to answer the following other questions: 

  • What is the adequate dosage and duration of exposure required to show an effect?

  • What proportion reduction in zinc deficiency can we expect to see as a result of zinc fortification, and which groups may require additional/complementary interventions? 

  • Which indicators should be recommended for evaluating zinc fortification programs?

  • What do we know about novel/alternative vehicles for zinc fortification? 

In parallel, the Zinc Fortification Task Force also wants to capture the lessons learnt and identify knowledge and resource gaps in countries with existing national zinc fortification programs. Which evidence did they act on? Which barriers are they facing? Likewise, the Task Force plans to explore the perspectives of countries with a high burden of zinc deficiency without zinc fortification in place, and the feasibility of zinc fortification as a successful strategy in such settings. 

We hope that the results from the activities in this first phase of the Zinc Fortification Task Force will be available by July 2020, and that this effort will help inform renewed global commitments to food fortification. 

 

References

  1. Hess SY, Brown KH. Impact of zinc fortification on zinc nutrition. Food Nutr Bull. 2009 Mar;30(1 Suppl):S79-107. 

  2. Shah D, Sachdev HS, Gera T, De-Regil LM, Peña-Rosas JP. Fortification of staple foods with zinc for improving zinc status and other health outcomes in the general population. Cochrane Database Syst Rev. 2016 Jun 9;(6):CD010697.

  3. Keats EC, Neufeld LM, Garrett GS, Mbuya MNN, Bhutta ZA. Improved micronutrient status and health outcomes in low- and middle-income countries following large-scale fortification: evidence from a systematic review and meta-analysis. Am J Clin Nutr. 2019 Jun 1;109(6):1696-1708.

Read more about strategies for promoting zinc nutrition here.