Modeling the Potential of Household-Level Maize Processing to Reduce the Burden of Zinc Deficiency Among Women of Childbearing Age in Malawi
Abstract Objectives Dietary phytate is a potent inhibitor of zinc absorption. Phytate levels of cereals can be reduced by basic household processing techniques such as soaking, germinating, and fermenting. The objective of this study was to model the potential of such techniques to reduce the burden of zinc deficiency in Malawi, where high-phytate maize is a dietary staple. Methods Using nationally representative household consumption data and food composition tables, we estimated daily phytate and zinc intakes for individuals in Malawi. We then applied a mathematical model of zinc absorption based on total dietary zinc and phytate to calculate the apparent absorbed zinc for each individual. Using the Cut-Point method described by the Institute of Medicine, we determined the proportion of each physiological group with absorbed zinc below their mean requirements. We then simulated the reduction in dietary phytate resulting from maize processing and estimated the new burdens of zinc deficiency. We estimated the impact at various coverage levels and compared the results against an alternative model using zinc-biofortified maize. Results Nationally, 34% of females age 14–18 and 23% of females over age 18 were at risk of zinc deficiency. Only 13% of women of childbearing age met the zinc requirement for pregnancy, while less than 4% met the requirement for breastfeeding. The burden of zinc deficiency was highest in the South where maize intake was highest. The simulation of phytate reduction from household processing found that with 40% coverage, the proportion of at-risk females age 14–18 fell below 23%, while the proportion over age 18 fell to 14%. The potential benefits were greatest in the South, where the proportion of women at risk was reduced by over a third. Biofortification also reduced zinc deficiency, however the modeled impact of processing was greater than biofortification for all regions and subgroups. Conclusions Household food processing techniques may be an important strategy to reduce the burden of zinc deficiency among vulnerable women in Malawi. These techniques are low-cost and not widely practiced at present. Behavior change interventions to promote them must consider culture, gender norms, and drivers of food preference. Food-based approaches such as these should be given greater attention in nutrition and health policy and programming. Funding Sources None.