Iodised salt has become uncool but many of us need to eat more iodine

During my university days, a biology lecturer who dedicated his work to addressing global dietary deficiencies heavily emphasized the importance of iodine. He advocated for the use of iodised salt, praising it as a major public health breakthrough that could enhance the IQ of entire populations. His advice echoes in my mind whenever I navigate the salt aisle in a supermarket.

Lately, however, I have noticed that iodised salt is becoming a rarity on store shelves. It is overshadowed by more visually appealing options like Cornish sea salt crystals, Himalayan pink rock salt, smoked salt flakes, and Kosher salt. The remaining iodised salt containers appear quite plain and unfashionable, which raises concerns for me about whether we might lose the health benefits of this simple yet significant additive.

Iodine is a vital nutrient that the thyroid gland utilizes to produce hormones essential for regulating metabolism, growth, digestion, heart rate, and body temperature.

Adequate iodine intake is crucial during pregnancy, as thyroid hormones are key to fetal brain development. Studies suggest that even mild to moderate iodine deficiencies during pregnancy can decrease intelligence by 0.3 to 13 IQ points. Iodine is also crucial for brain development and thyroid function in children. Reports highlight that extremely selective eaters, who are short for their age, struggle academically, and experience constant fatigue, often suffer from iodine deficiency. For both children and adults, iodine deficiency can cause goitre, a neck swelling due to an enlarged thyroid gland seeking more iodine.

Natural sources of iodine include seaweed and seafood. Cow’s milk is also a source because iodine is often added to cattle feed, and iodine-based disinfectants are used in dairy farming. Fruits, vegetables, and grains can absorb iodine from soil, but levels vary significantly. Areas like Switzerland and Michigan, once part of the “goitre belt,” have historically low soil iodine levels, resulting in high goitre rates, affecting up to 70% of children in some Swiss towns.

Switzerland pioneered the introduction of iodised salt in 1922 by adding a small amount of iodine to regular table salt. This initiative nearly eradicated goitre, boosted children’s growth, and increased IQs, which led to more students completing high school and university, as noted by economist Dimitra Politi.

Two years later, Michigan introduced iodised salt, followed by other parts of the US and many countries worldwide. The introduction of iodised salt has been credited with contributing to the global rise in IQ during the 20th century. The late endocrinologist Gerald Burrow once remarked to The New York Times that for just five cents per person annually, it could enhance the intelligence of an entire population.

However, with goitre now largely forgotten, iodised salt faces a decline in popularity. It struggles to compete with the aesthetic appeal of pink Himalayan salt. Some trendy salts even highlight their lack of iodine additives, implying potential health risks. Some parents avoid iodised salt over concerns about chemical additives, despite iodine being a natural element.

Simultaneously, as iodised salt usage at home decreases, consumption of processed and takeaway foods, which typically use non-iodised salt to prevent reactions during processing, has increased. The shift towards vegan diets and plant-based milk alternatives further reduces iodine intake.

Consequently, a study in November revealed a doubling in the number of Americans with insufficient iodine intake since 2001, with 46% of pregnant women affected.

The situation in the UK is similar, with reproductive-aged women showing iodine levels significantly below adequate thresholds, according to a January study. In Australia, 62% of pregnant and breastfeeding women are iodine-deficient. Conversely, areas like parts of Japan face issues with excessive iodine consumption, leading to other thyroid problems.

Public health experts are urging people in the US, UK, and Australia to return to using iodised salt to prevent cognitive and thyroid health issues and the resurgence of goitre.

In an era where the supplement industry thrives and people invest in various pills for brain health with little evidence of effectiveness, iodine supplements and salts, despite their proven benefits, are often overlooked. This paradox is perplexing to me.

Regardless of current trends, I am committed to searching supermarket shelves for iodised salt, heeding the advice of my university lecturer, rather than opting for the more visually appealing pink salt.