The Rise and Fall of Universal Salt Iodization in Vietnam: Lessons Learned for Designing Sustainable Food Fortification Programs With a Public Health Impact

Switching the World's Salt Supply-Learning from Iodization to Achieve Potassium Enrichment

Sodium is an essential dietary component, but excess sodium intake can lead to high blood pressure and an increased risk of cardiovascular disease. Many national and international bodies, including the World Health Organization, have advocated for population-wide sodium reduction interventions. Most have been unsuccessful due to inadequate sodium reduction by food industry and difficulties in persuading consumers to add less salt to food. Recent research highlights potassium-enriched salt as a new, feasible, acceptable, and scalable approach to reducing the harms caused by excess sodium and inadequate potassium consumption. Modeling shows that a global switch from regular salt to potassium-enriched salt has the potential to avert millions of strokes, heart attacks, and premature deaths worldwide each year. There will be many challenges in switching the world's salt supply to potassium-enriched salt, but the success of universal salt iodization shows that making a global change to the manufacture and use of salt is a tractable proposition. This in-depth review of universal salt iodization identified the importance of a multisectoral effort with strong global leadership, the support of multilateral organizations, engagement with the salt industry, empowered incountry teams, strong participation of national governments, understanding the salt supply chain, and a strategic advocacy and communication plan. Key challenges to the implementation of the iodization program were costs to government, industry, and consumers, industry concerns about consumer acceptability, variance in the size and capabilities of salt producers, inconsistent quality control, ineffective regulation, and trade-related regulatory issues. Many of the opportunities and challenges to universal salt iodization will likely also be applicable to switching the global salt supply to iodized and potassium-enriched salt.

Global Coverage of Mandatory Large-Scale Food Fortification Programs: A Systematic Review and Meta-Analysis

Food fortification with micronutrients is widely implemented to reduce micronutrient deficiencies and related outcomes. Although many factors affect the success of fortification programs, high population coverage is needed to have a public health impact. We aimed to provide recent global coverage estimates of salt, wheat flour, vegetable oil, maize flour, rice, and sugar among countries with mandatory fortification legislation. The indicators were the proportion of households consuming the: food, fortifiable food (that is, industrially processed), fortified food (to any extent), and adequately fortified food (according to national or international standards). We estimated the number of individuals reached with fortified foods. We systematically retrieved and reviewed all applicable evidence from: published reports and articles from January 2010 to August 2021, survey lists/databases from key organizations, and reports/literature received from key informants. We analyzed data with R statistical package using random-effects meta-analysis models. An estimated 94.4% of households consumed salt, 78.4% consumed fortified salt (4.2 billion people), and 48.6% consumed adequately fortified salt in 64, 84, and 31 countries, respectively. Additionally, 77.4% of households consumed wheat flour, 61.6% consumed fortifiable wheat flour, and 47.1% consumed fortified wheat flour (66.2 million people) in 15, 8, and 10 countries, respectively, and 87.0% consumed vegetable oil, 86.7% consumed fortifiable oil, and 40.1% consumed fortified oil (123.9 million people) in 10, 7, and 5 countries, respectively. Data on adequately fortified wheat flour and vegetable oil and coverage indicators for maize flour, rice, and sugar were limited. There are major data gaps on fortification coverage for most foods except salt. All countries with mandatory fortification programs should generate and use more coverage data to assess program performance and adjust programs as needed to realize their potential to reduce micronutrient deficiencies (PROSPERO CRD42021269364).

A generic theory of change-based framework with core indicators for monitoring the effectiveness of large-scale food fortification programs in low- and middle-income countries

Large-scale food fortification (LSFF) programs are widely implemented in low- and middle-income countries (LMIC) to alleviate micronutrient deficiencies. However, these programs may not achieve the desired impact due to poor design or bottlenecks in program implementation. Monitoring and evaluation (M&E) frameworks and a set of agreed indicators can help to benchmark progress and to strengthen the evidence-base of effectiveness in a standardized way. We aimed to formulate recommendations towards core indicators for evaluating the effectiveness of LSFF programs with their associated metrics, methods, and tools (IMMT). For this, we used a multi-method iterative approach, including a mapping review of the literature, semi-structured interviews with international experts, compilation of a generic Theory of Change (ToC) framework for LSFF program delivery, and selection of IMMT for M&E of LSFF programs at key stages along the ToC delivery framework. Lastly, we conducted exploratory, qualitative interviews with key informants in Nigeria to explore experiences and perceptions related to the implementation of LSFF programs in Nigeria's context, and their opinion towards the proposed set of core IMMT. The literature search resulted in 14 published and 15 grey literature documents, from which we extracted a total of 41 indicators. Based on the available literature and interviews with international experts, we mapped a ToC delivery framework and selected nine core indicators at the output, outcome and impact level for M&E of the effectiveness of LSFF programs. Key informants in Nigeria revealed that the main bottlenecks for implementation of the proposed IMMT are related to the lack of technical capacity, equipment, laboratory infrastructure, and financial resources. In conclusion, we propose a set of nine core indicators for enabling comprehensive M&E of the effectiveness of LSFF programs in LMIC. This proposed set of core indicators can be used for further evaluation, harmonization and integration in national and international protocols for M&E of LSFF programs.

Changes of Iodine Nutritional Status in the Elderly after Replacing Iodized Salt with Non-Iodized Salt for Half a Year

China has issued the "Reform Plan of the Salt Industry System" in 2016 and it is necessary to attach the importance to the changes of iodine nutritional status of those people who might consume non-iodized salt for a long time. Forty-six elderly subjects were recruited and replaced iodized salt with non-iodized salt for 6 months. Urine iodine concentration (UIC), dietary iodine intake, thyroid function, thyroid B-ultrasound, and plasma iodine were monitored during the follow-up period. The median dietary iodine intakes of the baseline, the 1st, 2nd,3rd, 4th, and 6th month were 255.3 µg/d, 183.6 µg/d, 164.6 µg/d, 179.2 µg/d, 139.4 µg/d, and 146.9 µg/d, respectively. The median UIC of baseline and follow-up was 155.7 (111.0-263.1) µg/L and 69.7(36.7-119.8) µg/L, respectively. The proportion of urinary iodine less than 50 g/L at the baseline and follow-up was 3.0 (0 ~ 8.9)% and 36.0 (33.1 ~ 38.9)%, respectively. Dietary iodine intake had a significant correlation with urine iodine. Six subjects (15.4%) had abnormal thyroid function. Three subjects (7.7%) had first-onset new nodules or enlarged solid nodules and the median UIC of these three subjects during the follow-up period was 39.8 µg/L, which was significantly lower than that of other subject (74.0 µg/L). T4 and T3 had a significant correlation with plasma iodine. The importance of monitoring and evaluating iodine nutrition of people consuming non-iodized salt should be stressed to prevent the potential poor iodine nutrition and iodine deficiency diseases.

Knowledge, attitude and behaviour of university students regarding salt and iodine: a multicentre cross-sectional study in six countries in Europe and Asia

Background

Strategies to reduce salt intake are encouraged to be implemented in parallel with those that aim to ensure iodine adequacy at the population level. The aim of the present study was to assess and compare knowledge, attitudes and behaviours related to salt and iodine among students in Europe and Asia.

Methods

A multicentre cross-sectional study was conducted with 2459 university students in total (42.7% males, median age 21 years) from four countries in Europe and two countries in Asia. Data were collected with the use of a self-administered questionnaire, and univariate and multivariate statistical analyses were performed to explore any association between variables.

Results

Only 6.5% of all participants knew the correct salt recommendations. Nearly a quarter of them (24.4%) found salt recommendations confusing and/or contradictory. There were significant differences between European and Asian participants, with those from Europe being better informed about salt recommendations, but significantly less knowledgeable about iodine. The reported frequency of use of salt and salt-containing sauces either at the table or for cooking, as well as knowledge about ways to reduce salt intake among those who indicated to make conscious efforts to do so, differed significantly between countries. Significant differences between countries were also observed with respect to the type of salt used, with about one third of all participants (34%) not being aware of the kind of salt they used.

Conclusion

The results of this survey highlight serious salt- and iodine-related knowledge gaps among university students in Europe and Asia. Raising awareness and conducting information campaigns is needed to promote changes in behaviour that would result in a reduction of salt intake and conscious use of iodised salt at the individual level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-021-00593-5.

Excessive intake of iodine and low prevalence of goiter in school age children five years after implementation of national salt iodization in Shebedino woreda, southern Ethiopia

Background

Iodine is a trace element required for the synthesis of thyroid hormones. The multiple effects of iodine deficiency on human health are called iodine deficiency disorders (IDDs). IDDs have been common nutritional problems in Ethiopia. In 2012, Ethiopia launched a national salt iodization program to address IDDs. The objective of this study was to assess the effects of this program after 5 years by measuring urinary iodine concentration (UIC) and prevalence of goiter in school age children as well as household salt iodine concentration (SIC).

Methods

A school-based cross-sectional design was employed. After ethical approval, 408 children from eight randomly selected primary schools provided urine samples. UIC was analyzed by inductively coupled plasma mass spectrophotometry (ICP-MS). A 10 g salt sample was collected from each household of a sampled child. SIC was analyzed with a digital electronic iodine checker (WYD, UNICEF) and goiter was assessed by palpation.

Results

The mean (±SD) age of the children was 9 ± 2 years. The prevalence of goiter was 4.2% and no child had grade 2 goiter. The median (IQR) UIC was 518 (327, 704) μg/L and UIC ranged from 3.1 to 2530 μg/L. Of the salt samples, 15.6% were not adequately iodized (< 15 ppm), 39.3% were adequately iodized (≥15 to ≤40 ppm), and 45.1% were > 40 ppm. SIC ranged from 4.2 to 195 ppm. Of the mothers, 92% said iodized salt prevents goiter and 8% mentioned prevents mental retardation.

Conclusions

In 2017 iodine deficiency was no longer a public health problem in the study area. However, the high variability in UIC and SIC and excessive iodine intake are of great concern. It is vital to ensure that salt is homogenously iodized at the production site before being distributed to consumers.

Universal Salt Iodisation: Lessons learned from Cambodia for ensuring programme sustainability

Iodine deficiency is the leading cause of preventable intellectual disability in the world, but it has been successfully prevented in most countries through universal salt iodization (USI). In 2011, Cambodia appeared to be an example of this success story, but today, Cambodian women and children are once again iodine deficient. In 2011, Cambodia demonstrated high‐household coverage of adequately iodized salt and had achieved virtual elimination of iodine deficiency in school‐age children. However, this achievement was not sustained because the USI programme was dependent on external funding, and the national government and salt industries had not institutionalized their implementation responsibilities. Recent programmatic efforts, in particular the establishment of a regulatory monitoring and enforcement system, are turning the situation around. Although Cambodia has not yet fully regained the achievements of 2011 (only 55% of tested salt was adequately iodized in 2017 compared with 67% in 2011), the recent steps taken by the government and the salt industry point to greater sustainability of the USI programme and the long‐term prevention of iodine deficiency in children, women, and the general population.

National nutrition strategies that focus on maternal, infant, and young child nutrition in Southeast Asia do not consistently align with regional and international recommendations

We examined the consistency of national nutrition strategies and action plans (NNS) focusing on maternal, infant, and young child nutrition in Southeast Asia with regional and international recommendations. Between July and December 2017, we identified and extracted information on context, objectives, interventions, indicators, strategies, and coordination mechanisms from the most recent NNS in nine Southeast Asian countries. All NNS described context, objectives, and the following interventions: antenatal care, micronutrient supplementation during pregnancy, breastfeeding promotion, improved complementary feeding, nutrition in emergencies, and food fortification or dietary diversity. Micronutrient supplementation for young children was included in eight NNS; breastfeeding promotion during pregnancy and support at birth in seven; and school feeding, deworming, and treatment of severe acute malnutrition in six. All NNS contained programme monitoring and evaluation plans with measurable indicators and targets. Not all NNS covered wasting, exclusive breastfeeding, low birthweight, and childhood overweight. Strategies for achieving NNS goals and objectives were health system strengthening (nine), social and behaviour change communication (nine), targeting vulnerable groups (eight), and social or community mobilization (four). All addressed involvement, roles and responsibilities, and collaboration mechanisms among sectors and stakeholders. There was a delay in releasing NNS in Indonesia, Myanmar, and the Philippines. In conclusion, although Southeast Asian NNS have similarities in structure and contents, some interventions and indicators vary by country and do not consistently align with regional and international recommendations. A database with regularly updated information on NNS components would facilitate cross-checking completeness within a country, comparison across countries, and knowledge sharing and learning.

Prevalence of goiter among children aged 8-10 in Binh Dinh province, Vietnam in 2016-2017

Objective

The study was conducted to estimate the goiter prevalence, and the median urine iodine concentrations among schoolchildren aged 8–10 in Binh Dinh province, Vietnam.

Methods

A school-based cross-sectional survey was carried out from May 2016 to May 2017. A multistage, proportional-to-population-size sampling method with 30 clusters was used. The children were examined by palpation for the presence or absence of goiter based on the criteria of the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), International Council for the Control of Iodine Deficiency (ICCIDD); urinary iodine was determined in microplates by a modification of the Sandell-Kolthoff reaction. The Chi-square test was used to compare prevalences, and the Chi-square test for trend was employed to assess the trend of goiter prevalence and urine iodine levels by age and economic-social areas.

Results

1800 pupils from 8 to 10 years old including 900 males and 900 females were examined and 300 among them were tested for the urinary iodine concentration (UIC). The prevalence of goiter among schoolchildren was 6.6%. The prevalence of goiter tended to increase in areas with disadvantaged conditions, among which the urban areas occupied the lowest prevalence (5%) while the mountainous areas and Midland took the highest (8.8%) (the p-value of 0.0193). The median UIC of the study group was 159.9 µg/L; the 25^th and 75^th percentile value was 103 µg/L and 230.2 µg/L, respectively.

Conclusion

According to the WHO/UNICEF/ICCIDD classification, the goiter prevalence indicated that some regions of Binh Dinh province appeared to be slightly affected by iodine deficiency. These have characterized an important public health challenge, highlighting the need to eliminate iodine deficiency disorders in these areas.

Iodine Status of Taiwanese Population in 2013: 10 Years After Changing From Mandatory to Voluntary Salt Iodization

BACKGROUND

In 2003, Taiwan's iodine policy changed from mandatory to voluntary. The Nutrition and Health Survey in Taiwan (NAHSIT) 2001-2002 for schoolchildren showed adequate iodine nutrition, while NAHSIT 2005-2008 for adults showed the iodine status was at borderline adequacy.

OBJECTIVE

To investigate the iodine status of the Taiwanese population from schoolchildren to adulthood 10 years after the change of the salt iodization policy.

METHOD

Urinary iodine was measured in samples from subjects in NAHSIT 2013.

RESULTS

The median urinary iodine concentration (UIC) of the Taiwanese population aged 6 years and above in 2013 was 96 μg/L, indicating mild iodine deficiency. The median UIC of 6- to 12-year-old schoolchildren was 124 μg/L (interquartile range [IQR]: 92-213 μg/L), and 115 μg/L (IQR: 80-166 μg/L), 125 μg/L (IQR: 74-161 μg/L), 73 μg/L (IQR: 52-131 μg/L), and 78 μg/L (IQR: 52-132 μg/L) in populations aged 13 to 18 years, 19 to 44 years, 45 to 64 years, and ≥65 years, respectively. Declining iodine nutrition in age groups ≥45 years old was noted that the median UIC of populations aged 45 to 64 years and ≥65 years was 99 and 88 μg/L, respectively, in NAHSIT 2005-2008. The median UIC of schoolchildren was not lower than that during the mandatory salt fortification period, but the distribution of urinary iodine levels signified a dietary pattern change.

CONCLUSION

Wide-ranging variation in iodine nutrition levels was observed in different age groups. Universal salt iodization, as suggested by the World Health Organization, should be the best strategy to achieve adequate iodine nutrition.

The legislative framework for salt iodization in Asia and the Pacific and its impact on programme implementation

Objective

Fortification of food-grade (edible) salt with iodine is recommended as a safe, cost-effective and sustainable strategy for the prevention of iodine-deficiency disorders. The present paper examines the legislative framework for salt iodization in Asian countries.

Design

We reviewed salt iodization legislation in thirty-six countries in Asia and the Pacific. We obtained copies of existing and draft legislation for salt iodization from UNICEF country offices and the WHO’s Global Database of Implementation of Nutrition Actions. We compiled legislation details by country and report on commonalities and gaps using a standardized form. The association between type of legislation and availability of iodized salt in households was assessed.

Results

We identified twenty-one countries with existing salt iodization legislation, of which eighteen were mandatory. A further nine countries have draft legislation. The majority of countries with draft and existing legislation used a mandatory standard or technical regulation for iodized salt under their Food Act/Law. The remainder have developed a ‘stand-alone’ Law/Act. Available national surveys indicate that the proportion of households consuming adequately iodized salt was lowest in countries with no, draft or voluntary legislation, and highest in those where the legislation was based on mandatory regulations under Food Acts/Laws.

Conclusions

Legislation for salt iodization, particularly mandatory legislation under the national food law, facilitates universal salt iodization. However, additional important factors for implementation of salt iodization and maintenance of achievements include the salt industry’s structure and capacity to adequately fortify, and official commitment and capacity to enforce national legislation.