Fortifying staple foods can dramatically reduce global nutrient deficiencies at minimal cost, but gaps persist, and the risk of excess intake underscores the need for smarter, more balanced nutrition strategies.
Study: Impact of large-scale food fortification programmes on micronutrient inadequacies and their implementation costs: a modelling analysis. Image credit: udra11/Shutterstock.com
Expanded guideline-based food fortification programs are cost-effective interventions that can reduce the prevalence of micronutrient deficiencies, particularly iron and iodine deficiencies, according to a modeling study published in The Lancet. However, complementary approaches are essential to improve diet quality.
Deficiency-linked health risks
Inadequate micronutrient levels are associated with blindness, intellectual impairment, lower productivity, poor growth, and death. Deficiencies in one of four micronutrients (iron, zinc, folate, and vitamin A) affect about 372 million children under 5 years and 1.2 billion women of reproductive age who are not pregnant. Many other micronutrients slip through gaps due to missing measurements.
This has led to the use of dietary intake data as proxies. The existing literature indicates that iodine, vitamin E, calcium, iron, several B vitamins, and vitamin C intake are inadequate for 4-5 billion people, according to modeling analyses. These could be overestimates, as some micronutrients, such as iodine, are routinely added to salt and other staples.
Large-scale food fortification (LSFF)
Large-scale food fortification (LSFF) is a public health strategy to reduce the prevalence of micronutrient deficiencies. Current estimates put the number of countries practicing this at over 150. Fortified foods range from salt and edible oils to flours and grains. Currently, these programs prevent 87 % of iodine deficiency, with salt iodization being the least expensive at 1 cent per person.
These appear to be promising and cost-effective approaches if properly designed and executed. However, their global impact across all population groups has not been well quantified, since most studies focus on women and preschool children, and effects can vary substantially between countries depending on diet and program implementation.
In the current study, the authors aimed to understand the impact and associated costs of these programs on a global scale, the first such study, according to them. They used data from the Global Fortification Data Exchange to input fortification standards, compliance, and coverage, thus adjusting earlier estimates of impact. The model focused on 13 micronutrients and estimated inadequate intake across 185 countries, adjusting for LSFF programs and using modeled dietary intake distributions.
Fortification reduces micronutrient inadequacy
The researchers found that, compared to no fortification, current programs prevent 7 billion inadequate person-nutrient intakes per year (the sum of the number of people with inadequate intakes of each of the 13 micronutrients). The costs come to just over $1 billion across the five fortified foods each year, or on average, 18 cents per person.
Iodine fortification is estimated to have eliminated 3.3 billion inadequate intakes, and iron fortification 1.4 billion. Despite such programs, 38.6 billion inadequate intakes remain uncorrected, highlighting substantial gaps in diet quality and program reach.
Improving compliance nearly doubles global fortification impact
Improved program compliance to at least 90 % would nearly double their effectiveness, preventing 13.1 billion inadequate intakes. The cost would be 23 cents per person, for a total of $3.48 billion per year. Vitamin A would be the largest gainer, preventing 1.1 billion inadequate intakes globally.
Aligning standards adds gains but less than compliance
If, in addition to improving compliance, fortification standards were also met, over 4 billion more inadequate intakes would be prevented, an estimated total of 17.2 billion, at a cost of $6.56 billion per year (63 cents per person), although gains are smaller because many countries already fortify above recommended levels.
Compliance, fortification, and coverage
With a comprehensive expansion of fortification coverage, in addition to the above measures, 24.7 billion inadequate intakes could be prevented. The cost would be $9.19 billion, or $1.15 per person, per year.
Most of this would go to wheat flour fortification, with rice flour accounting for less than 25 % and other foods 1-8 % each. Expanding these programs most cost-effectively would involve targeting countries with limited coverage where a few industrially manufactured staple foods are widely consumed, though the magnitude of the benefit varies widely depending on national dietary patterns and infrastructure.
Risk of excessive intake
The researchers also emphasize the need to conform to WHO (World Health Organization) guidelines and set up monitoring systems. These would help ensure that such programs are based on each country's needs and do not pose an unacceptable risk of excessive intake. This applies mostly to iodine, selenium, and zinc.
The modeled changes could put over 15 % of the world’s population at risk of excess intake of iodine and zinc, though this risk is unevenly distributed across countries and depends on baseline intake levels and program design. However, there were significant country-specific differences in both prevention rates and excess intake risks.
Vulnerable groups require additional targeted nutrition interventions
Even with all these enhancements, there would still be 20.9 billion inadequate intakes remaining uncorrected. This points to the need for other approaches to complement food fortification, including improving the quality and accessibility of the average diet.
This should include diverse, nutritious foods in their native contexts, but it remains economically out of reach for 2.6 billion people. Additional interventions may be required to meet the increased needs of very young children and of women during pregnancy and lactation.
Limitations
The model provides several useful estimates of LSFF's reach and cost, but it has important limitations. It relies on the Global Dietary Database, which assumes fixed calorie intakes across countries and may introduce inaccuracies. It also uses Food and Agricultural Organization national food balance data, which do not account for food waste or small-scale production. Compliance is estimated using proxy measures, which could overstate program impact, and missing data are similarly filled using proxy values that may introduce bias.
In addition, the analysis excludes biofortification and supplementation programs, despite their role in delivering multiple micronutrients. Cost estimates are based on fixed premix prices, although large-scale implementation could reduce them by up to 48 %. Finally, the deterministic modeling approach does not capture uncertainty in the estimates.
Fortification must pair with diet diversity and supplementation
LSFF is a cost-effective and scalable intervention, capable of assisting billions of people who cannot afford or access a high-quality diet. The study assesses three steps that could close existing gaps in the programs while safeguarding safety.
Objective micronutrient measurements are required to validate these modeled estimates as accurate reflections of actual deficiency. In addition, future research should strengthen the global database by including missing programs, such as biofortification, and by improving data collection in the neediest countries.
However, the researchers highlight the need for comprehensive policies to bridge this gap. “Long-term success hinges on parallel investments in dietary diversity, supplementation, and robust monitoring systems to ensure equitable, safe access to essential micronutrients.”
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