Iodine Deficiency Disorders: A Global Public Health History

Iodine deficiency has been a recognized global public health issue for over a century, prompting fortification programs worldwide. A historical and public-health-focused overview, not intended as medical guidance.

An Old, Geographic Problem

For most of history, iodine intake depended on where people lived. Communities in mountain valleys, river floodplains and inland regions far from the sea often ate food grown in low-iodine soil. Visible thyroid enlargement in those regions was described in writing and art for centuries, long before anyone connected it to a missing nutrient.

Making the Connection

The pieces came together in the 19th and early 20th centuries. Iodine was discovered in 1811. In 1895, Eugen Baumann found that the thyroid gland is unusually rich in iodine. Then, between 1917 and 1922, studies of schoolchildren in Akron, Ohio, led by David Marine, showed that adequate iodine intake made a measurable difference to thyroid health in a low-iodine region. Public health officials now had a cause and a practical answer.

The First Fortification Programs

Switzerland, an Alpine nation with naturally low-iodine soil, introduced iodized salt in 1922. The United States followed in 1924, starting in Michigan. See A Short History of Iodized Salt in the U.S. Over the following decades, other countries adopted their own programs, with strong results wherever iodized salt reached most households.

A Broader Picture Emerges

By the second half of the 20th century, researchers understood that iodine matters for more than the thyroid's size. Adequate iodine during pregnancy and early childhood supports normal brain development, which made iodine intake a priority for maternal and child health. In 1983, the term "iodine deficiency disorders" was introduced to describe the full range of effects of insufficient iodine across a population.

Going Global

• 1985: the International Council for Control of Iodine Deficiency Disorders (ICCIDD) was founded. It's now called the Iodine Global Network.
• 1990: the World Summit for Children set a goal of virtually eliminating iodine deficiency.
• 1993: the World Health Organization and UNICEF recommended universal salt iodization, meaning all salt for human and animal use should be iodized.

The Results

Universal salt iodization is considered one of the most successful and cost-effective public health efforts in history. The number of countries classified as iodine deficient fell from more than 100 in the early 1990s to roughly 20 by around 2020. Read more in How Fortification Programs Actually Work.

Where Things Stand Now

The work isn't finished. Some regions still lack consistent access to iodized salt, and in wealthier countries, changing diets, from processed food to specialty salts and plant-based milks, have raised new questions about iodine intake in specific groups, particularly during pregnancy. See Is Iodine Deficiency Coming Back? and Global Iodine Intake.

Frequently Asked Questions

Is iodine deficiency still common in the U.S.?
U.S. averages are generally considered adequate, but intake varies a lot by diet. Groups that avoid dairy, eggs, seafood and iodized salt can take in less, and pregnant women have higher needs.

Is this historical formula still relevant, or just a marketing story?
It's both. The historical formula has held up because the underlying chemistry works, not just because it's old — but longevity alone isn't a health claim, and any supplement decision should be made with your own health context in mind.

How common is iodine deficiency today?
Rates vary widely by region and diet. For signs, causes, and how it's assessed, see our complete guide to iodine deficiency.

Shop Lugol's Solution — the traditional, trusted way people have supported their iodine intake for over 200 years.

Jessica Bennett writes about clean, ingredient-conscious living for the Iodine Journal.

This article is for general educational purposes only and has not been evaluated by the FDA. It is not intended to diagnose, treat, cure, or prevent any disease, and is not a substitute for advice from a qualified healthcare provider — especially if you are pregnant, nursing, taking thyroid medication, or managing a thyroid condition.