Who is at risk of not getting enough iodine?

December 12, 2025 •

4 min read

Globally, an estimated 2 billion people have insufficient iodine intake, a crucial nutrient for thyroid function and overall health. While the widespread implementation of iodized salt programs has reduced deficiency in many regions, several populations remain vulnerable due to dietary habits, geographic location, or increased physiological needs.

Quick Summary

Populations with a higher risk for iodine deficiency include pregnant and lactating women, vegans, people in mountainous or inland areas with poor soil iodine, and those who do not use iodized salt. Inadequate intake can lead to thyroid dysfunction and severe developmental issues.

Key Points

Pregnant Women: Due to increased metabolic and fetal demands, pregnant and lactating women are highly susceptible to iodine deficiency and require increased intake.
Vegan and Vegetarian Diets: Excluding seafood and dairy, key dietary sources of iodine, puts vegans and vegetarians at a higher risk of deficiency without careful planning or supplementation.
Geographic Location: Individuals living in mountainous or inland regions far from the sea, where soil iodine is naturally low, have historically been at higher risk.
Avoiding Iodized Salt: People who choose not to use iodized table salt or rely on processed foods made with non-iodized salt can easily develop insufficient iodine intake.
Goitrogen Consumption: Diets rich in foods containing goitrogens (like cabbage and soy), combined with low iodine intake, can interfere with the thyroid's ability to utilize iodine effectively.
Fetal and Child Consequences: Iodine deficiency is the leading cause of preventable brain damage worldwide, impacting fetal and child cognitive development, growth, and survival.

Populations at High Risk for Iodine Deficiency

Iodine is an essential trace mineral that the body cannot produce on its own. It is vital for the synthesis of thyroid hormones, which regulate metabolism, growth, and development. When intake is insufficient, the body's processes can suffer. Several distinct groups face a heightened risk of developing a deficiency.

Pregnant and Lactating Women

Pregnant women require significantly more iodine to support both their own metabolism and the developing fetus. During this period, the mother's body must produce enough thyroid hormone for two. Iodine is critical for the fetal brain and central nervous system development, which begins early in gestation.

Increased Demand: A pregnant woman's daily iodine requirement increases from 150 micrograms (mcg) to 220 mcg, and even higher for lactating women at 290 mcg.
Consequences for the Fetus: Severe maternal iodine deficiency during pregnancy can cause irreversible intellectual disability and growth problems in the child. In the most extreme cases, it can lead to cretinism, a condition characterized by severe mental and physical delays. Even mild to moderate deficiency can result in subtle cognitive impairment and lower IQ scores in children.
High Renal Excretion: During pregnancy, increased renal clearance of iodine also contributes to the higher demand, making supplementation particularly important.

Individuals with Restricted Diets

Dietary choices play a significant role in iodine intake, especially for those who exclude major sources of the mineral. Common sources include seafood and dairy products.

Vegans and Vegetarians: Plant-based diets, especially strict vegan diets that exclude all animal products, pose a risk for iodine deficiency if not carefully planned. Dairy products are a major source of iodine in many Western diets, and vegans must seek alternative sources, such as fortified foods or supplements. Studies have shown that vegans and vegetarians often have lower median urinary iodine concentrations compared to omnivores.
People Avoiding Iodized Salt: While iodized salt has been a public health success story in controlling iodine deficiency, many people today are reducing salt intake or opting for non-iodized varieties like sea salt, kosher salt, or Himalayan salt. Processed foods, which account for a large portion of sodium intake in some countries, are often made with non-iodized salt.

Populations in Geographically Limited Regions

Iodine content in soil varies dramatically across the globe. Areas far from coastlines and in mountainous regions often have iodine-poor soil, as the mineral evaporates from the sea and is deposited on land by rain.

Mountainous Areas: Historically, iodine deficiency was most prevalent in mountainous areas like the Himalayas, Andes, and Alps, where dietary iodine is naturally low.
Inland Regions: People living in inland regions where seafood is not a dietary staple are also at higher risk. This includes parts of Central Asia, Central Africa, and Eastern Europe.

Factors That Exacerbate Risk

Beyond diet and geography, other factors can increase the risk of developing an iodine deficiency.

Goitrogens in Food: Certain foods, called goitrogens, can interfere with the thyroid's ability to use iodine. Consuming very large quantities of these foods, particularly when iodine intake is already low, can worsen a deficiency. Goitrogens are found in cruciferous vegetables like broccoli, cauliflower, cabbage, and soy.
Pre-existing Thyroid Conditions: Individuals with certain pre-existing thyroid conditions, especially those with autoimmune thyroiditis, may be more sensitive to fluctuations in iodine intake.
Smoking: Smoking has been shown to increase the risk of iodine deficiency, though the mechanisms are complex.

Comparison of Iodine Risk Factors


Risk Group	Primary Cause	Severity of Consequences	Prevention Strategies
Pregnant & Lactating Women	Increased physiological demand	High, especially for fetal brain development	Prenatal vitamins with iodine, iodized salt, supplementation
Vegans & Vegetarians	Dietary exclusion of key sources	Moderate, if diet is not fortified	Use of iodized salt, fortified plant milks, or targeted supplements
Inland & Mountainous Dwellers	Low environmental iodine in soil	Historically severe, but mitigated by salt iodization	Consistent use of iodized salt, food fortification programs
Goitrogen Consumers	Interference with iodine uptake	Mild to moderate, primarily with low base intake	Ensure adequate iodine intake, moderate consumption of raw goitrogenic foods
Individuals Avoiding Iodized Salt	Dietary choice	Moderate to severe, depending on other dietary sources	Awareness of iodine sources, check food labels, use iodized salt consciously

How to Assess and Mitigate Iodine Deficiency

Identifying iodine deficiency is a critical first step. It is generally assessed at the population level through median urinary iodine concentration (UIC). However, individuals can work with a healthcare provider to understand their personal risk.

Clinical Signs: An enlarged thyroid gland, or goiter, is often an early and visible sign of deficiency. Other symptoms of hypothyroidism, a result of chronic deficiency, include fatigue, unexplained weight gain, and sensitivity to cold.
Dietary Sources: To mitigate risk, focus on consuming iodine-rich foods, which include:
- Fish (cod, tuna)
- Shrimp, seaweed, and other seafood
- Dairy products (milk, yogurt, cheese)
- Eggs
Supplementation: For those in high-risk groups, such as pregnant women or vegans, a daily supplement containing iodine is often recommended. Not all multivitamins contain iodine, so it is essential to check the label.
Salt Awareness: Be mindful that gourmet or specialty salts (sea salt, Himalayan) are not reliable sources of iodine. Rely on iodized table salt for adequate intake.

Conclusion: Proactive Steps for Iodine Sufficiency

While universal salt iodization has been a remarkable public health achievement, iodine deficiency remains a significant concern for specific groups around the world. Pregnant and lactating women, vegans, and those in iodine-poor geographic areas are particularly vulnerable. The consequences of insufficient iodine, especially on fetal and child brain development, are severe and largely preventable. By being aware of dietary choices, understanding geographic limitations, and utilizing iodized salt or supplements as needed, individuals can take proactive steps to ensure adequate iodine intake and protect their health. Effective monitoring and targeted interventions for at-risk populations are key to preventing the resurgence of iodine deficiency disorders.

For more detailed information on global iodine status, consult the World Health Organization data and guidelines.

Frequently Asked Questions

Symptoms of iodine deficiency can include an enlarged thyroid gland (goiter), fatigue, weight gain, increased sensitivity to cold, dry skin, hair loss, and problems with memory and learning.

Pregnant women have higher iodine requirements. The American Thyroid Association recommends that women who are pregnant, planning to become pregnant, or breastfeeding take a daily multivitamin supplement containing 150 mcg of iodine, in addition to using iodized salt.

No. Only iodized table salt has been fortified with iodine. Specialty salts like sea salt, kosher salt, and Himalayan salt are not reliable sources of iodine unless specifically labeled as iodized.

It can be challenging for vegans to get sufficient iodine from diet alone, as major sources like dairy and seafood are excluded. Vegans should consider using iodized salt, consuming fortified plant milks, or taking an iodine supplement to ensure adequate intake.

These foods contain goitrogens, compounds that can interfere with iodine uptake, but they typically only pose a risk for iodine deficiency when consumed in very large quantities alongside an already low iodine intake. For most people with adequate iodine intake, this is not a concern.

Iodine deficiency can be diagnosed through blood tests that measure thyroid-stimulating hormone (TSH) and thyroid hormone levels. For population-level assessment, urinary iodine concentration (UIC) is the most common method.

If left untreated, severe or long-term iodine deficiency can lead to serious health complications. This includes hypothyroidism, which affects metabolism, and in infants and children, it can cause irreversible intellectual and developmental disabilities.