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.