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