Combatting Iodine Deficiency: The National Iodine Deficiency Disorder Control Programme

Iodine is one of those nutrients most people rarely think about – yet it plays a critical role in human health. A deficiency in this trace element can lead to a range of serious disorders, from goitre and hypothyroidism to irreversible brain damage in children. In India, where over 200 million people have historically been at risk of iodine deficiency disorders (IDDs), the government launched a dedicated national programme to tackle this public health crisis. Known today as the National Iodine Deficiency Disorders Control Programme (NIDDCP), this initiative has been instrumental in transforming India’s iodine nutrition landscape over several decades.

What are iodine deficiency disorders? 🔗

Iodine is an essential micronutrient required in small but critical amounts – roughly 100 to 150 micrograms daily – for the production of thyroid hormones. These hormones regulate metabolism, growth, and neurological development. When the body doesn’t get enough iodine through food, the thyroid gland cannot produce adequate hormones, leading to a group of conditions collectively called iodine deficiency disorders (IDDs).

The most visible sign of iodine deficiency is goitre, a swelling of the thyroid gland in the neck. But the damage goes far deeper. According to the National Institutes of Health, approximately 2 billion people globally suffer from iodine deficiency, with around 50 million showing clinical symptoms. IDDs can cause hypothyroidism, physical and mental retardation, deaf-mutism, cretinism (a severe and irreversible form of intellectual disability), dwarfism, and neuromotor defects. In pregnant women, iodine deficiency is particularly dangerous – it can result in stillbirths, spontaneous abortions, and congenital abnormalities in the developing fetus.

The World Health Organization identifies iodine deficiency as the most common preventable cause of brain damage in children worldwide. This makes it not just a medical concern, but a developmental and economic issue that affects entire communities and nations.

Why is India particularly vulnerable? 🔗

The root cause of iodine deficiency lies in the soil. In regions where the soil has been leached of its iodine content – typically mountainous and inland areas – crops grown on that land are iodine-poor. People who rely on locally grown food in these regions receive very little iodine in their diets. India, with its vast geographic diversity including the Himalayan belt, the Gangetic plains, and several tribal and remote regions, has historically had widespread pockets of iodine-deficient populations.

Government surveys conducted over the years have found that out of 414 districts surveyed across all states and union territories, 337 were found to be endemic – meaning the prevalence of IDDs exceeded 5%. An estimated 71 million people in India have been affected by goitre and other iodine-related disorders. Importantly, iodine deficiency does not discriminate by income – it depends on the geophysical properties of the land where food is grown, meaning both affluent and economically weaker households can be affected.

Origins of the programme: from NGCP to NIDDCP 🔗

India’s fight against iodine deficiency began in the early 1960s. After a successful pilot project using iodized salt in the Kangra Valley of Himachal Pradesh in 1962, the Government of India launched the National Goitre Control Programme (NGCP). The initial focus was on providing iodized salt to endemic areas and identifying the geographic extent of the problem.

However, by the early 1990s, scientific understanding of iodine deficiency had expanded significantly. Researchers recognized that the consequences of low iodine intake extended far beyond goitre – affecting cognitive development, reproductive health, and overall physical growth. To reflect this broader understanding, the NGCP was renamed the National Iodine Deficiency Disorders Control Programme (NIDDCP) in August 1992. This change in nomenclature was not merely cosmetic; it signalled a shift from a narrow focus on goitre to a comprehensive approach addressing the entire spectrum of iodine deficiency disorders.

A pivotal policy decision had already been made in 1984, when the Central Council of Health recommended that all edible salt in India should be iodized. The phased implementation of this decision began in 1986, laying the groundwork for what would become one of the world’s largest micronutrient supplementation programmes.

Key objectives and strategies of NIDDCP 🔗

The NIDDCP operates under the Ministry of Health and Family Welfare and is implemented across all states and union territories. The programme has two overarching targets: reducing the prevalence of IDDs to below 5% in the population and ensuring that 100% of households consume adequately iodized salt – defined as salt containing at least 15 parts per million (ppm) of iodine.

Universal salt iodization 🔗

The central strategy of NIDDCP is universal salt iodization (USI). Salt was chosen as the vehicle for iodine supplementation because it is consumed universally, in relatively consistent quantities, and is inexpensive. The programme works to replace common salt with iodized salt across the country. India now produces approximately 65 lakh metric tonnes of iodized salt annually, which is sufficient to meet the dietary needs of its entire population. Several states and union territories have also banned the sale of non-iodized salt to strengthen compliance.

Surveys and assessments 🔗

Regular district-level surveys are a core component of the programme. These surveys assess the magnitude and distribution of IDDs across different regions. Resurveys are conducted every five years to measure the impact of iodized salt distribution and to track changes in the prevalence of goitre and other disorders over time.

Laboratory monitoring 🔗

Quality control is maintained through a robust laboratory network. A National Reference Laboratory has been established at the National Centre for Disease Control (NCDC) in Delhi. Four regional laboratories – at the National Institute of Nutrition (Hyderabad), the All India Institute of Hygiene and Public Health (Kolkata), AIIMS (Delhi), and NCDC (Delhi) – conduct training, monitoring, and quality testing of iodized salt and urinary iodine levels. At the state level, 35 states and union territories have set up their own IDD monitoring laboratories.

Information, education, and communication (IEC) 🔗

Awareness campaigns form another critical pillar. The programme uses television spots, radio jingles, posters, video films, wall paintings, pamphlets, and community events to educate the public about the importance of using iodized salt. Global IDD Prevention Day, observed on October 21, is celebrated across the country with events involving schools, NGOs, and community groups. At the grassroots level, ASHA (Accredited Social Health Activist) workers play a key role – they receive performance-based incentives for testing salt samples at the household level using salt testing kits and spreading awareness within their communities.

Monitoring and measuring impact 🔗

The effectiveness of the NIDDCP is measured through multiple indicators, including the Total Goitre Rate (TGR), household consumption of adequately iodized salt, and median urinary iodine concentration (UIC) in the population. UIC is the primary biochemical marker recommended by the WHO and UNICEF for assessing a population’s iodine status.

Significant progress over the decades 🔗

The programme has delivered remarkable results. The Total Goitre Rate across the country has declined significantly since the programme’s inception. According to the National Family Health Survey (NFHS-5), conducted between 2019 and 2021, India achieved 94.3% household consumption of adequately iodized salt. This is a dramatic improvement – the Coverage Evaluation Survey of 2009 had found that only about 71% of households were consuming adequately iodized salt.

More recent data from 2024 further reinforces this progress. Salt samples analysed by states and union territories between April and December 2024 showed that 93.3% of samples were adequately iodized (iodine content above 15 ppm) through volumetric testing, and 92.4% were of good quality as assessed by salt testing kits.

The India Iodine Survey 2018-19 🔗

A landmark exercise in tracking India’s iodine status was the India Iodine Survey 2018-19, commissioned by Nutrition International. This was the first national-level survey to estimate iodine concentrations in household salt using the gold-standard iodometric titration method. It covered over 21,000 households across all states and union territories and also assessed the iodine nutrition status of women of reproductive age (15-49 years). The survey provided crucial sub-national data that helped identify remaining gaps and informed future programme planning.

Regional disparities persist 🔗

Despite the overall national progress, disparities remain. Analysis of NFHS-5 data revealed that some regions lag behind. Andhra Pradesh recorded the lowest consumption of adequately iodized salt among all states, partly because pickling and canning industries in some coastal areas continue to use raw sea salt. Certain union territories like Dadra and Nagar Haveli and Daman and Diu also showed lower coverage. These disparities highlight the need for continued targeted interventions in specific regions.

Challenges in implementation 🔗

While the NIDDCP has achieved impressive national-level outcomes, several challenges continue to affect its reach and effectiveness.

Availability and affordability in remote areas 🔗

In some rural, tribal, and geographically remote areas, the supply chain for iodized salt remains weak. Non-iodized salt is sometimes cheaper and more readily available, making it the default choice for economically disadvantaged households.

Loss of iodine during storage and cooking 🔗

Iodine in salt is volatile and can be lost through improper storage (exposure to moisture, heat, and light) and high-temperature cooking. Even if a household purchases iodized salt, the actual iodine consumed may be lower than expected. Public education on proper storage – keeping salt in airtight, dry containers – is essential but often overlooked.

Industrial use of non-iodized salt 🔗

The food processing, pickling, and canning industries in some parts of India continue to use non-iodized salt. This is significant because processed and preserved foods form a growing share of the Indian diet, and their exemption from iodization requirements creates a loophole in the universal salt iodization strategy.

Awareness gaps 🔗

While national awareness has improved considerably, pockets of low awareness persist, particularly among less educated and economically marginalized populations. Many people remain unaware of the invisible consequences of iodine deficiency – such as reduced cognitive potential in children – and may not prioritize iodized salt over cheaper alternatives.

The global context 🔗

India’s efforts through NIDDCP are part of a wider global movement to eliminate iodine deficiency. Salt iodization programmes now reach approximately 88% of the world’s population, and the number of countries with adequate iodine intake has nearly doubled from 67 in 2003 to 118 in 2020. The economic argument is compelling too – improved cognitive development and future productivity linked to adequate iodine intake suggest a potential global economic benefit of nearly $33 billion.

However, iodine deficiency has not been entirely eliminated anywhere. Changing dietary patterns – including the growing popularity of plant-based diets that may lack iodine-rich dairy and seafood, and increasing consumption of processed foods made with non-iodized salt – are creating new challenges even in developed countries. This underscores the need for sustained vigilance and adaptive strategies.

The road ahead for India 🔗

The NIDDCP has brought India from a situation where millions suffered from visible goitre and preventable intellectual disability to one where over 94% of households use adequately iodized salt. This is a significant public health achievement. But the goal of 100% coverage and reducing IDD prevalence below 5% everywhere requires continued effort.

Key priorities going forward include strengthening the supply chain in underserved areas, ensuring iodization standards are extended to the food processing industry, maintaining the quality of iodized salt from production to the point of consumption, sustaining IEC activities to keep awareness high, and conducting regular monitoring to quickly identify and address emerging gaps. The role of ASHA workers and community-level testing through salt testing kits will remain central to the programme’s grassroots impact.

The story of the NIDDCP demonstrates that a well-designed, sustained, and evidence-based public health intervention – built around a simple, inexpensive solution like salt iodization – can have transformative effects at a national scale.

What do you think? Given that India has achieved over 94% household coverage of iodized salt, what additional steps should be taken to close the remaining gap – especially in states and communities that are still lagging behind? And should iodization requirements be extended to salt used in the food processing industry to ensure comprehensive protection?

References

1. https://www.who.int/data/nutrition/nlis/info/iodine-deficiency
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC6284174/
3. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(03)14920-3/fulltext
4. https://dghs.gov.in/content/1348_3_NationalIodineDeficiency.aspx
5. https://nhm.gov.in/index1.php?lang=1&level=3&sublinkid=1054&lid=230
6. https://dghs.mohfw.gov.in/niddcp.php
7. https://pubmed.ncbi.nlm.nih.gov/8690502/
8. https://www.pib.gov.in/PressNoteDetails.aspx?NoteId=153355&ModuleId=3
9. https://data.unicef.org/topic/nutrition/iodine/
10. https://www.sciencedirect.com/science/article/pii/S0022316623724437
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13. https://www.who.int/europe/news/item/28-06-2024-people-in-the-who-european-region-at-greater-risk-of-iodine-deficiency-due-to-changing-diets