Feeling Salty? Choose Iodized!

For many Americans, getting groceries involves a simple drive or an eco-friendly walk to the nearest supermarket. As we calmly stroll through the aisles, we navigate towering columns of miscellaneous products in search of everything needed to successfully stave off hunger and starvation. As we pass the irresistible aisles of chips and cookies, we finally arrive at the messiah of both heart function and simultaneous dysfunction (in excess): salt. 

In this moment, comes the big question: iodized or regular salt? Whenever I go shopping with my mom, I watch as she unflinchingly grabs the box containing iodized salt.

What is iodized salt, and how is it different from its regular counterpart? Iodized salt is table salt mixed in with small amounts of the trace element iodine. The element iodine is an essential micronutrient that is naturally present in some foods, especially in seafood and dairy products. In the small amounts that it is needed, iodine plays a crucial role in human metabolism and mental development. The thyroid gland, a butterfly-shaped organ at the base of your neck, releases thyroid hormones that control metabolism. Iodine is an essential part of these hormones. Iodine deficiencies lead to thyroid enlargement and can cause a lump called a goiter to appear.

While its specific role in thyroid hormone production was only discovered within the last century, iodine’s medicinal capabilities were realized far earlier. Chinese writings dated back to 3600 BC recorded decreases in goiter size upon ingestion of seaweed and burnt sea sponge, which contain large amounts of the element. Several thousands of years later, in 1819, a Swiss physician named J.F. Coindet used iodine tincture (an elemental iodine in solution) to reduce the size of goiters in his patients. Iodine’s seemingly miraculous propensity to heal led to physicians prescribing it for countless other afflictions ranging from inflammation to gangrene.

Even more significant than its effects on thyroid function, iodine’s role in fetal development is crucial, so much so that pregnant women are advised to take supplements if their iodine levels are flagged. Iodine deficiencies are associated with stillbirth and miscarriages. Furthermore, children of mothers with severe iodine deficiencies tend to have intellectual disabilities and growth disorders. This is not limited to extreme cases, as even slight iodine deficiencies can contribute to a lower IQ. In a study done in the 1930s, researchers compared the intelligence of children born just before 1924 (the year the iodization of salt began) and those born thereafter with a standardized intelligence test. In the initially lowest-iodine areas, the introduction of iodized salt had amazing results: men from this region born in 1924 or later had an average IQ that was 15 points higher than that of their predecessors.

For Americans, iodized salt is so commonplace that we barely notice the ramifications of an iodine deficiency. During the 1920s, widespread iodization of salt began and this largely improved thyroid function and reduced goiter appearance for millions of Americans. While iodine deficiencies were common a few generations ago, most middle-aged and younger Americans have never experienced it. The implementation of salt iodization through effective legislation has drastically reduced goiter occurrences and increased IQ values in adolescents.

However, this is not the case for many other countries. Iodine deficiency still affects up to 2 billion people worldwide, including 285 million adolescents. Currently, iodine deficiency is the main preventable cause of brain damage in children, and so a lack of iodine has disastrous consequences for these iodine-deficient countries. In 2003, the World Health Organization (WHO) conducted a study on the levels of urinary iodide in populations of different continents. Whereas only 9.8% of the population of the Americas were found to be iodine-deficient, this number was 42.6% in Africa, 39.8% in Southeast Asia, and 56.9% in Europe. As stated above, such low levels of iodine have the capacity to severely damage thyroid function and brain development. Moreover, while the presence of overt hypothyroidism (not caused by any sort of iodine deficiency) is roughly the same throughout the world, much higher rates of hypothyroidism correlate with lower iodine consumption. In Pescopagano, a notably iodine-deficient village in southern Italy, the prevalence of hypothyroidism was observed to be twice the value of those of iodine-sufficient countries in 1999. Many factors, such as living in areas in iodine-deficient soil, consuming goitrogens (which reduce intake of iodine in thyroid and include popular foods like soy, cabbage, and broccoli) and lacking adequate knowledge of the importance of iodine are the root causes of these deficiencies. Mandated salt iodization has solved this problem for some, but in many other areas, inadequate legislation and even less enforcement result in iodine deficiencies continuing to be an issue.

While it is only considered a micronutrient, iodine in deficiency has effects on a population that certainly cannot be considered microscopic. From lowering IQ points to causing stillbirths, iodine deficiencies result in severe problems for those citizens living in iodine-deficient regions. The numbers of these regions are disappointingly high, and it is paramount that great attention be brought to this disparity.