Key Considerations for Policymakers-Iodized Salt as a Vehicle for Iron Fortification: Current Evidence, Challenges, and Knowledge Gaps

Abstract

Could DFS help prevent iron deficiency and anemia? Studies in controlled settings (efficacy) demonstrate that double-fortified salt (DFS; iron added to iodized salt) reduces the prevalence of anemia and iron deficiency anemia. Studies in program settings (effectiveness) are limited and reported differing levels of DFS coverage, resulting in mixed evidence of impact on anemia. What iron formulations are available and how do they affect iodized salt? Ferrous sulfate and encapsulated ferrous fumarate (both with various enhancers and/or coating materials) are the main iron formulations currently in use for DFS. Adding iron to iodized salt may lead to adverse changes in the product, specifically discoloration and losses in iodine content. These changes are greatest when the iodized salt used in DFS production is of low quality (e.g., contain impurities, has high moisture, and is of large crystal size). DFS requires iodized salt of the highest quality and a high-quality iron formulation in order to minimize adverse sensory changes and iodine losses. Appropriate packaging of iodized salt is also important to prevent losses. What is known about the minimum requirements to manufacture DFS? DFS producers must use high-quality refined iodized salt meeting the minimum standards for DFS production (which is higher than standards for salt intended for iodization alone), and an iron formulation for which there are rigid quality-assurance measures to ensure consistent quality and blending techniques. The actual proportion of iodized salt meeting the stringent requirements necessary for DFS production is unclear, but likely to be low in many countries, especially those with fragmented salt industries and a low proportion of industrially produced salt. What are the financial implications of adding iron to iodized salt? As a result of higher input costs both for input salt and the iron compound, DFS is more expensive to produce than iodized salt and thus has a higher production cost. Various grades of iodized salt are produced and consumed in different sectors of the market. Experience in India indicates that, on average, producing DFS costs 31-40 US dollars/metric ton or 0.03-0.04 US dollars/kg more than high-quality refined iodized salt. The exact impact of this production-level cost difference on profit margins and consumer price is specific to the conditions of different salt markets. Factors such as transport costs, customary wholesale and retail mark-ups, and taxes all vary greatly and need to be assessed on a case by case basis. Is DFS in alignment with salt-reduction efforts? The WHO has long recognized that salt iodization is an important public health intervention to achieve optimal iodine nutrition and is compatible with salt-reduction goals. Fortification of salt (with any nutrient) should not be used to justify or encourage an increase in salt intake to the public. Any effort to expand salt fortification to other nutrients should be done in close consultation with WHO and those working on salt reduction. What has been the experience with DFS delivery under different platforms? To date, DFS has been introduced into the retail market and in social safety net (primarily in India) programs, but sensory changes in DFS have been raised as concerns. The higher price for DFS has limited expansion in the retail market. In social safety net programs where the cost of DFS is subsidized for beneficiaries, programs must consider long-term resourcing for sustainability. Overall: The optimal production and delivery of DFS are still under development, as many challenges need to be overcome. There is a beneficial impact on hemoglobin in efficacy trials. Thus, if those conditions can be replicated in programs or the technology can be adapted to better fit current production and delivery realities, DFS may provide an effective contribution in countries that need additional food-fortification vehicles to improve iron intake.

Keywords: fortification; iodine; iodization; iron; salt.