Seventeen per cent of the world's population is estimated to be at risk of inadequate zinc intake, which could in part be addressed by zinc fortification of widely consumed foods. We conducted a review of efficacy and effectiveness studies to ascertain the effect of zinc fortification [postharvest fortification of an industrially produced food or beverage; alone or with multiple micronutrients (MMN)] on a range of health outcomes. Previous reviews have required that the effect of zinc be isolated; because zinc is always cofortified with MMN in existing fortification programs, we did not impose this condition. Outcomes assessed were zinc-related biomarkers (plasma or serum, hair or urine zinc concentrations, comet assay, plasma fatty acid concentrations, and the proportion of and total zinc absorbed in the intestine from the diet), child anthropometry, morbidity, mortality, cognition, plasma or serum iron and copper concentrations, and for observational studies, a change in consumption of the food vehicle. Fifty-nine studies were included in the review; 54 in meta-analyses, totaling 73 comparisons. Zinc fortification with and without MMN increased plasma zinc concentrations (efficacy, n = 27: 4.68 μg/dL; 95% CI: 2.62–6.75; effectiveness, n = 13: 6.28 μg/dL; 95% CI: 5.03–7.77 μg/dL) and reduced the prevalence of zinc deficiency (efficacy, n = 11: OR: 0.76, 95% CI: 0.60–0.96; effectiveness, n = 10: OR: 0.45, 95% CI: 0.31–0.64). There were statistically significant increases in child weight (efficacy, n = 11: 0.43 kg, 95% CI: 0.11–0.75 kg), improvements in short-term auditory memory (efficacy, n = 3: 0.32 point, 95% CI: 0.13–0.50 point), and decreased incidence of diarrhea (efficacy, n = 3: RR: 0.79, 95% CI: 0.68–0.92) and fever (efficacy, n = 2: RR: 0.85, 95% CI: 0.74–0.97). However, these effects cannot be solely attributed to zinc. Our review found that zinc fortification with or without MMN reduced the prevalence of zinc deficiency and may provide health and functional benefits, including a reduced incidence of diarrhea.

Large-scale food fortification (LSFF) can increase dietary micronutrient intake and improve micronutrient status. Here we used food balance sheet data from the Food and Agriculture Organization of the United Nations to estimate current country-specific prevalences of inadequate zinc intake. We assessed the potential effects of improving existing LSFF programmes for cereal grains or implementing new programmes in 40 countries where zinc deficiency is a potential public health problem. Accounting for LSFF programmes as currently implemented, 15% of the global population (1.13 billion individuals) is estimated to have inadequate zinc intake. In countries where zinc deficiency is a potential public health problem, the implementation of high-quality mandatory LSFF programmes that include zinc as a fortificant would substantially increase the availability of zinc in the national food supply, reducing the estimated prevalence of inadequate zinc intake by up to 50% globally. Investments in strong LSFF programmes could have a substantial impact on population zinc status.

Context: Previous reviews have focused on evaluating the efficacy and effectiveness of rice fortification, despite the need to also understand the outcomes of micronutrient retention, organoleptic properties, and acceptability to inform nutrition programs.Objective: This systematic review aims to consolidate existing evidence on micronutrient retention, organoleptic properties, and acceptability of fortified rice.Data Sources: Eligible articles were identified from 22 electronic databases and personal referrals and reviews.Study Selection: Studies on rice fortified via extrusion or coating technologies were included in the review if they reported outcomes in at least 1 of 3 domains: micronutrient retention, organoleptic or physicochemical properties, and acceptability (evaluated by sensory tests and consumer surveys). Any years of publication and study populations were considered for inclusion. A total of 15 391 articles were screened, yielding 49 for inclusion.Data Extraction: Study results were summarized descriptively through discussions by intervention conditions, study population, measurement methods, and key findings. The included studies were independently reviewed by 2 of the 3 authors, and all 3 authors reached consensus on the quality and major findings from the included articles.Results: Extrusion and coating fortification technologies were found to be comparable across studies that assessed retention, organoleptic properties, and acceptability. Cooking fortified rice in excess water increased micronutrient loss for both technologies. Fortified kernels containing ferric pyrophosphate, zinc oxide, or zinc sulfate showed the most positive results for all outcomes reviewed, while retention rates of vitamin A in multiple-micronutrient-fortified rice were variable.Conclusions: The current practice of fortifying rice with ferric pyrophosphate provides high micronutrient stability and results in rice with organoleptic properties and consumer acceptance levels comparable to those of unfortified milled rice, although it presents challenges regarding the effect of vitamin A–fortified rice on vitamin A status.

The addition of iodine to edible salt has been one of the most important public health successes of the past half century, enabling most countries to achieve optimal iodine intake and protect the brains of unborn children from the adverse consequences of iodine deficiency. Salt has been an ideal vehicle for this effort because of its near universal and narrow range of consumption, relative ease of technology for salt iodization, and capacity for virtually all salt producers to add iodine. As a result of the success of salt iodization, there has been growing interest in using salt as a vehicle for other important micronutrients, particularly the addition of iron to iodized salt to produce double-fortified salt (DFS), to combat the persistent problem of iron deficiency and iron deficiency anemia. Because of this growing interest in DFS and the need for a comprehensive review of evidence to support the viability of this intervention, the Iodine Global Network (IGN) initiated a global consultation to gather all available data on different aspects of DFS. IGN identified 4 key areas considered essential to understand for a successful fortification intervention: 1) efficacy and effectiveness, or how well DFS produces a health impact in controlled and real-life settings; 2) technical considerations for production, or what are the minimum requirements to manufacture DFS; 3) program implementation to describe experiences thus far with the delivery of DFS across multiple platforms; and 4) comparison of DFS with other iron fortification efforts to determine the comparative advantage of DFS to improve iron intake and prevent iron deficiency anemia. This preface provides an overview of the DFS Consultation objectives, process, and objectives.

(1) Background: Fortifying maize and wheat flours with folic acid has effectively reduced neural tube defect-affected births. However, maize and wheat flours may not be widely consumed in all countries; further reduction in neural tube defect-affected births could benefit from the identification of alternative food vehicles. We aimed to use dietary intake or apparent consumption data to determine alternative food vehicles for large-scale fortification with folic acid in low-income and lower-middle-income countries (LILMICs) and identify current research related to examining the technological feasibility of fortifying alternative foods with folic acid. (2) Methods: We identified 81 LILMICs, defined by the World Bank’s (WB) 2018 income classifications. To identify dietary intake or apparent consumption, we reviewed WB’s Microdata Library and Global Health Data Exchange for national surveys from 1997–2018. We reviewed survey reports for dietary intake or apparent consumption data and analyzed survey datasets for population coverage of foods. We defined alternative food vehicles as those that may cover/be consumed by ≥30% of the population or households; cereal grains (maize and wheat flours and rice) were included as an alternative food vehicle if a country did not have existing mandatory fortification legislation. To identify current research on fortification with folic acid in foods other than cereal grains, we conducted a systematic review of published literature and unpublished theses, and screened for foods or food products. (3) Results: We extracted or analyzed data from 18 national surveys and countries. The alternative foods most represented in the surveys were oil (n = 16), sugar (n = 16), and salt (n = 14). The coverage of oil ranged from 33.2 to 95.7%, sugar from 32.2 to 98.4%, and salt from 49.8 to 99.9%. We found 34 eligible studies describing research on alternative foods. The most studied alternative foods for fortification with folic acid were dairy products (n = 10), salt (n = 6), and various fruit juices (n = 5). (4) Conclusions: Because of their high coverage, oil, sugar, and salt emerge as potential alternative foods for large-scale fortification with folic acid. However, except for salt, there are limited or no studies examining the technological feasibility of fortifying these foods with folic acid.