Double fortification of salt with folic acid and iodine

Protocol for a community-based, household-randomised, dose-response trial to assess the acceptability, nutritional effects and safety of double-fortified salt containing iodine and folic acid compared with iodised salt among non-pregnant Ethiopian women of reproductive age (DFS-IoFA)

INTRODUCTION

The prevalence of neural tube defects (NTDs) is higher in Ethiopia than most other countries, and ~84% of Ethiopian women of reproductive age (WRA) have folate insufficiency, a major risk factor for NTDs. Salt fortification with folic acid is a potential strategy to improve women's folate status, but data are needed on the acceptability, nutritional impact and safety of folic acid fortification of iodised salt.

METHODS AND ANALYSIS

The study is designed as a community-based, household-randomised, dose-response trial. A total of 360 non-pregnant WRA 18-49 years of age will be randomly assigned to one of three intervention arms: (1) iodised salt fortified with 30 ppm folic acid to provide ~200 µg folic acid/day; (2) iodised salt fortified with 90 ppm folic acid to provide ~600 µg folic acid/day; or (3) iodised salt (comparator). The preweighed salts will be delivered to participants' homes biweekly for 26 weeks; unused salt will be collected and weighed. Fasting, venous blood samples will be collected at baseline, end line and a randomly assigned intermediate time point for assessment of folate, iodine, vitamin B12 and other micronutrient status biomarkers. Women's dietary intakes, including discretionary salt consumption, will be measured using weighed food records; 24-hour urine specimens will be analysed for sodium and iodine excretion. Primary outcomes are women's consumption of study salts, change in biomarkers of folate and iodine status and prevalence of adverse events. Results will be analysed using analysis of covariance models to estimate group mean differences for continuous outcomes, controlling for baseline measurements, and log-binomial or modified Poisson regressions for categorical outcomes. Prespecified effect modifications will be explored.

ETHICS AND DISSEMINATION

The study has been approved by the Ethiopian Public Health Institute's Institutional Review Board, and the protocol has been registered with ClinicalTrials.gov (registration number NCT06223854). Study results will be published in open access scientific journals and disseminated nationally in Ethiopia.

TRIAL REGISTRATION NUMBER

NCT06223854.

Modeling the Contribution of Multiple Micronutrient Fortification of Salt to Daily Nutrient Intake Among the Ethiopian Population

Background

Salt is an affordable commodity and has wide coverage regardless of economic and social status and, hence, could be suitable vehicle for multiple micronutrient fortification.

Objectives

This study aimed to simulate the contribution folic acid and zinc fortification of iodized salt to nutrient intake among the Ethiopian population.

Methods

The 2013 Ethiopian National Food Consumption Survey and various food composition tables were used to estimate baseline individual-level micronutrient intake. Usual intake was estimated using the Simulating Intake of Micronutrients for Policy Learning and Engagement macro tool. Discretionary salt consumption was calculated from total salt intake estimated using urinary sodium excretion. Fortificant addition rates were set to obtain maximum nutrient intake while simultaneously constraining that population with intake above the tolerable upper intake level to <5%. Addis Ababa and Somali (N = 2271), the regions with relatively the lowest and highest micronutrient deficiency prevalence in Ethiopia, were selected.

Result

Baseline median intake of Zn was below the estimated average requirement for all demographic groups. Inadequate Zn intake ranged from 73% to 99%, the highest prevalence being observed among women in lower class of wealth quintiles from Somali region. Dietary folate inadequacy was as low as 2% among men in Addis Ababa but almost all (99%) women from Somali region had inadequate folate intake. Calculated discretionary salt intake was 7.5 g/d for adult men and women and 3.4 g/d for children. With addition 0.8 mg Zn and 30 μg of folic acid per gram of salt, multiple salt fortification is estimated to reduce Zn inadequacy by 38 percentage points in urban areas and19 percentage points in rural areas. Modeled reduction in folate inadequacy were 18% in urban areas and 22% in rural areas.

Conclusions

Multiple salt fortification could be an effective approach to address micronutrient adequacy in Ethiopia given efficacious, technological, and economical feasibility.

Expanding Fortification with Folic Acid: Thinking Outside the Cereal-Grain Box

(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.

Folic Acid-Fortified Iodized Salt and Serum Folate Levels in Reproductive-Aged Women of Rural India: A Nonrandomized Controlled Trial

Importance

India has a disproportionately high prevalence of neural tube defects, including spina bifida and anencephaly (SBA), causing a high number of stillbirths, elective pregnancy terminations, and child mortality; India contributes a large proportion of the global burden of SBA. Thirty years after folic acid was shown to be effective in reducing SBA prevalence, only about one-quarter of such births are prevented globally through cereal grain fortification.

Objective

To determine the association of folic acid-fortified iodized salt with serum folate concentrations among nonpregnant and nonlactating women of reproductive age.

Design, Setting, and Participants

This nonrandomized controlled trial using a preintervention and postintervention design was conducted in 4 rural villages in Southern India from July 1 to November 30, 2022. All households in the villages agreed to participate in the study. Preintervention and postintervention serum folate levels were analyzed among study participants at baseline and after 4 months, respectively.

Intervention

Consumption of approximately 300 µg/d of folic acid using double fortified salt (folic acid plus iodine). Median serum folate concentrations were assessed at baseline and 4 months.

Main Outcomes and Measures

Change in median serum folate levels between baseline and study end point as the primary outcome of the study.

Results

A total of 83 nonpregnant nonlactating women aged 20 to 44 years (mean [SD] age, 30.9 [5.1] years) were eligible for the study and provided serum samples for analysis at baseline and the end point of the intervention. The median serum folate concentration increased from 14.6 (IQR, 11.2-20.6) nmol/L at baseline to 54.4 (IQR, 43.5-54.4) nmol/L at end of study, a 3.7-fold increase from baseline to study end point. Two-tailed Wilcoxon signed rank test showed the median difference in preintervention and postintervention serum folate concentrations to be highly significant (P < .001). The participants found the salt acceptable in color and taste.

Conclusions and Relevance

Use of folic acid-fortified iodized salt was associated with increased serum folate concentrations in women of reproductive age. This novel evidence can inform public health policy to accelerate SBA prevention.

Trial Registration

ClinicalTrials.gov Identifier: NCT06174883.

Combination of in situ iodization and Haloferax spp. bacteria enrichment in salt crystallization process

Salts that meet the standard quality are enriched with micronutrients, such as potassium iodate, at least 30 ppm. The iodization can be carried out directly in crystallization ponds (in-situ iodization) in salt fields. This paper reports the effectiveness of in-situ iodization technology combined with the enrichment of Halophilic bacteria consortium and Haloferax spp. to produce bio-based NaCl salt. The brine was first crystallized under sunlight exposure for approximately five days with water temperatures of 32-39 °C and an average wind speed of 2.8-6.0 m/s in each pond with a dimension of 20 × 20 m. Following this, the performance of these bacteria was analyzed in terms of the resulting final concentration of KIO3 (ppm), NaCl concentration (v/v), and water content (v/v). Results showed that the treatment with in situ iodization and Haloferax spp. successfully produce better bio-based salt quality in terms of KIO3 level, NaCl purity, and water contents. Moreover, the method did not produce aqueous and solid wastes, unlike in the conventional salt industry. The optimum condition was found at 50 ppm of KIO3 with the addition of Haloferax spp. SEM analysis shows that the treatment using Haloferax spp. resulted in a larger rectangular and harder crystal salt than the controls.

Folic Acid and the Prevention of Birth Defects: 30 Years of Opportunity and Controversies

For three decades, the US Public Health Service has recommended that all persons capable of becoming pregnant consume 400 μg/day of folic acid (FA) to prevent neural tube defects (NTDs). The neural tube forms by 28 days after conception. Fortification can be an effective NTD prevention strategy in populations with limited access to folic acid foods and/or supplements. This review describes the status of mandatory FA fortification among countries that fortify (n = 71) and the research describing the impact of those programs on NTD rates (up to 78% reduction), blood folate concentrations [red blood cell folate concentrations increased ∼1.47-fold (95% CI, 1.27, 1.70) following fortification], and other health outcomes. Across settings, high-quality studies such as those with randomized exposures (e.g., randomized controlled trials, Mendelian randomization studies) are needed to elucidate interactions of FA with vitamin B12 as well as expanded biomarker testing.

Reduction of sodium chloride: a review

Sodium chloride (NaCl) is an enjoyable condiment. However, evidence is accumulating to indicate that an excessive intake of Na⁺ in food may lead to an increased risk of cardiovascular and cerebrovascular diseases. Previous systematic reviews have focused on replacing NaCl with other metal salts (e.g. KCl). However, new salty flavor enhancers (yeast extract, taste peptides, and odor compounds) have yet to be reviewed. This systematic review evaluates the methods for, and feasibility, of NaCl reduction. It defines NaCl reduction and considers the methods used for this purpose, especially the use of flavor enhancers (yeast extract, taste peptides, and odor compounds). © 2022 Society of Chemical Industry.

Folic acid fortification of double fortified salt

The addition of folic acid to Double Fortified Salt (with iron and iodine) aims to simultaneously ameliorate three major micronutrient deficiencies in vulnerable populations. To make Triple Fortified Salt, we added folic acid to the iodine solution (first method) and the iron premix (second method) that are used to fortify salt with iron and iodine. When added through the solution, sodium carbonate was needed to dissolve folic acid and to adjust pH. Alternately, folic acid was added either to the iron core or sandwiched between the core and TiO₂ layer of the iron premix. Folic acid and iodine were stable in all cases, retaining more than 70% of the added micronutrients after six months at 45 °C/60-70% relative hu. Adding folic acid to the premix's iron core is preferred as folic acid retention was slightly higher, and the added folic acid did not impact the salt's colour. The additional cost for adding the micronutrients to salt is about 27¢/person per year. Folic acid in the fortified salt made with the preferred method was stable in cooking and did not affect selected cooked foods' sensory properties. The technology is a cost-effective approach for simultaneously combating iron, iodine, and folic acid deficiencies.

Quadruple fortification of salt for the delivery of iron, iodine, folic acid, and vitamin B12 to vulnerable populations

A process for simultaneous delivery of iron, iodine, folic acid, and vitamin B₁₂ through salt as a potential and holistic approach to ameliorate anaemia and reduce maternal and infant mortality is presented. Two approaches for adding folic acid and B₁₂ to salt during double fortification with iron and iodine were investigated. Attempts to add both micronutrients through the iodine spray solution were unsuccessful. Hence, folic acid was added through a stabilized iodine solution, and B₁₂ was added through the iron premix. Four approaches used to incorporate B₁₂ into the iron premix were investigated: (1) co-extruding B₁₂ with iron, (2) spraying B₁₂ on the surface of the iron extrudate, (3) adding B₁₂ to the colour masking agent, and (4) adding B₁₂ to the outer coating. Of these approaches, coextrusion (1) was the best, based on the ease of production and stability of fortificants. The salt formulated with the solid iron-B₁₂ premix and sprayed iodine and folic acid solution contained 1000 ppm iron, 50 ppm iodine, 25 ppm folic acid, and 0.25 ppm B₁₂. Over 98% of B₁₂, 93% folic acid, and 94% iodine were retained after 6-month storage in the best formulation. This technology can simultaneously deliver iron, iodine, folic acid, and vitamin B₁₂ in a safe and stable salt enabling public health measures for improved health at a minimal additional cost.

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The process developed simultaneously delivers iron, iodine, folic acid, and vitamin B₁₂ through salt.

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The chemistry of interaction among the micronutrients guided the process development.

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Iron and vitamin B₁₂ were added as encapsulated particles (premix), while iodine and folic acid were added as a solution.

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Vitamin B₁₂ and folic acid had different pH range requirements; hence, they were incompatible in solution.

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Of the four iron-B₁₂ premix designs evaluated, the coextrusion of iron and vitamin B₁₂ was the best design for the process.

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The additional cost of adding these micronutrients to salt is about $0.30 per year per person; hence, very cost effective.

Modeling shows high potential of folic acid-fortified salt to accelerate global prevention of major neural tube defects

BACKGROUND

We estimated the global proportion of folic acid-preventable spina bifida and anencephaly (FAP SBA) potentially prevented through mandatory double fortification of iodized salt with folic acid.

METHODS

Using United Nations Children's Fund (UNICEF) and Global Fortification Data Exchange (GFDx) data sets, we modeled country-specific number of FAP SBA cases prevented annually using (a) current coverage of the salt in households worldwide and (b) expected daily amount of folic acid intake from folic acid-fortified iodized salt. Our evidence-based modeling strategy assumed mandatory folic acid fortification of salt at 20 ppm, and that at 200 μg/day intake of folic acid through fortified salt, should achieve 100% prevention of all FAP SBA in countries.

RESULTS

One hundred countries that have data on percent of households consuming iodized salt globally were examined; 55 of them have ≥80% households consuming iodized salt. Our model estimated approximately 180,000 cases of FAP SBA could be prevented in these 100 countries through folic acid-fortified iodized salt, and 150,000 of them would be in countries where ≥80% households consuming iodized salt that can be potentially fortified with folic acid. Salt fortification with folic acid could contribute to the prevention of about 65% global FAP SBA cases annually.

CONCLUSIONS

Our evidence-based model shows that there is high potential to prevent FAP SBA using folic acid-fortified iodized salt. Prevention will reach countries where there is a limited reach of centrally processed folic acid-fortified wheat or maize flour. If this intervention is made feasible by the salt industry, it can accelerate the prevention of FAP SBA significantly.

The Unfinished Agenda for Food Fortification in Low- and Middle-Income Countries: Quantifying Progress, Gaps and Potential Opportunities

Large-scale food fortification (LSFF) is a cost-effective intervention that is widely implemented, but there is scope to further increase its potential. To identify gaps and opportunities, we first accessed the Global Fortification Data Exchange (GFDx) to identify countries that could benefit from new fortification programs. Second, we aggregated Fortification Assessment Coverage Toolkit (FACT) survey data from 16 countries to ascertain LSFF coverage and gaps therein. Third, we extended our narrative review to assess current innovations. We identified 84 countries as good candidates for new LSFF programs. FACT data revealed that the potential of oil/ghee and salt fortification is not being met due mainly to low coverage of adequately fortified foods (quality). Wheat, rice and maize flour fortification have similar quality issues combined with lower coverage of the fortifiable food at population-level (<50%). A four-pronged strategy is needed to meet the unfinished agenda: first, establish new LSFF programs where warranted; second, systems innovations informed by implementation research to address coverage and quality gaps; third, advocacy to form new partnerships and resources, particularly with the private sector; and finally, exploration of new fortificants and vehicles (e.g. bouillon cubes; salt fortified with multiple nutrients) and other innovations that can address existing challenges.

Technology for Triple Fortification of Salt with Folic Acid, Iron, and Iodine

Abstract

As many of the maternal and child health complications result from folic acid, iron, and iodine deficiencies; it makes sense to combat these simultaneously. We have developed cost‐effective technology to deliver these three micronutrients simultaneously through salt. Our goal was to retain at least 70% of the micronutrients during 6 months of storage. The fortified salt was formulated by spraying a solution that contained 2% iodine and 0.5% or 1% folic acid onto salt and adding encapsulated ferrous fumarate. The formulated triple fortified salt contained 1,000 ppm iron, 50 ppm iodine, and 12.5 or 25 ppm folic acid. The spray solution and the salt were stored for 2 and 6 months respectively at 25, 35, and 45 °C 60 to 70% relative humidity. Even at 45 °C, over 70% of both iodine and folic acid were retained in the salt. The best formulation based on the color of the salt and stability of iodine and folic acid contained 12.5 ppm folic acid, 50 ppm iodine, and 1,000 ppm iron. These results indicate that iron, iodine, and folic acid can be simultaneously delivered to a vulnerable population through salt using the technology described. Also, the quality control of the process can be developed around pteroic acid that was detected as a primary degradation product of folic acid.

Practical Application

The technology developed is already transferred to India for industrial scale up. When fully operational, the technology will simultaneously solve iron, iodine, and folic acid deficiencies in vulnerable populations at a very low cost.

Preparation of Novel Iodized Salt with Natural Iodine-Rich Sources by Spray Drying

Marine products are rich in not only micronutrients but also iodine content. However, the applications of iodine in marine products in the food industry have not been studied extensively. Therefore, in this study, a novel iodized salt was prepared through a simple method for iodine extraction from natural iodine-rich sources and spray drying. Laminaria ochroleuca (kombu), Porphyra umbilicalis (nori), Undaria pinnatifida (wakame), and Haliotis discus hannai (abalone) were selected as natural iodine-rich sources. Through hot water extraction, iodine was extracted from the iodine-rich sources and iodized salt was successfully prepared with extracted iodine and sea salt by spray drying; extraction efficiency varied from 64.88% to 129.67%; yield, 38.45% to 57.09%; loading efficiency, 99.34% to 124.08%. Chemical interactions were assessed using Fourier transform infrared spectroscopy (FT-IR) and thermal dynamics was evaluated using differential scanning calorimetry (DSC). Morphology of the salt crystals was studied using scanning electron microscopy (SEM). Furthermore, a storage test was performed to investigate iodine loss due to temperature, relative humidity, and oxidation for 10 weeks in harsh condition. On comparing our salt with commercial products, novel iodized salts displayed similar or superior stability. Therefore, the novel iodized salt prepared in this study can be applied in the food industry.

PRACTICAL APPLICATION

Iodine is essential trace element and plays a key role in our body. Marine products such as Laminaria ochroleuca (Kombu), Porphyra umbilicalis (nori), Undaria pinnatifida (wakame), and Haliotis discus hannai (abalone) are known as iodine rich-sources. These products have high level of iodine, but iodine in marine products has not been used widely for food industry. Therefore, using iodine in natural sources, novel iodized salt was prepared with simple method (hot water extraction and spray drying). The novel iodized salt prepared in this study can be applied in the food industry.

A public health approach for preventing neural tube defects: folic acid fortification and beyond

In this paper we review the evidence basis for prevention of folic acid-sensitive neural tube defects (NTDs) through public health interventions in women of reproductive age (WRA), the proven vehicles for delivery of folic acid, and what is needed to effectively scale these, and provide a snapshot of potential innovations that require future research. Our primary focus is on the global situation affecting large-scale food fortification (LSFF) with folic acid, in particular the fortification of wheat flour and maize meal. Our overarching conclusion is that folic acid fortification is an evidence-based intervention that reduces the prevalence of NTDs, and that LSFF with folic acid is underutilized. Thus, food fortification with folic acid should be a component of most national public health strategies, in particular where folate status is insufficient and a fortifiable food vehicle, processed by a centralized industry, is consumed regularly by WRA. The evidence shows that there is still much work needed (1) to build the enabling environment and expand programs where there is currently no legislation, (2) to improve the low quality of delivery of existing programs, and (3) to measure and sustain programs by generating new coverage data and demonstrating evidence of impact in low- and middle-income countries.