The return of a forgotten health threat: iodine deficiency in kids
While iodised salt once eradicated the problem, dietary changes are leading to a rise in cases.
Iodine deficiency in children, once eradicated by fortified salt, has re-emerged due to dietary changes. Photo: Shutterstock A 13-year-old boy came to the clinic with a rapidly ballooning neck. Doctors were puzzled. Testing ruled out their first suspicion. But further tests pinpointed what they – and the boy – had been missing: iodine.
A century ago, iodine deficiency affected kids across large swathes of the US. It essentially disappeared after some food makers started adding it to table salt, bread and other foods, in one of the great public health success stories of the 20th century.
But today, people are getting less iodine because of changes in diet and food manufacturing.
Although most people are still getting enough, researchers have increasingly been reporting low levels of iodine in pregnant women, raising concerns about the potential impact on their newborns. There is also a very small but growing number of reports of iodine deficiency in kids.
“This needs to be on people’s radar,” said Dr Monica Serrano-Gonzalez, a Brown University doctor who treated the boy in 2021 in Providence, in the US state of Rhode Island.
What is iodine deficiency?
We need certain amounts of iodine to regulate our metabolism and stay healthy. It is also crucial for children’s brain function development.
One sign of insufficient iodine is a swelling of the neck, known as a goitre. The thyroid gland in the neck uses iodine to produce hormones that regulate the heart rate and other body functions (see graphic).
When there is insufficient iodine, the thyroid gland enlarges as it goes into overdrive to compensate.
At the beginning of the 20th century, goitre was common in children in certain inland parts of the United States, especially in a “goitre belt” stretching from Appalachia and the Great Lakes to the northwest United States. Some of the kids were unusually short, deaf, intellectually stunted and had other symptoms of a syndrome once known as “cretinism.”
Adding iodine to salt
Public health experts realised they couldn’t solve the problem by feeding everyone seaweed and seafood, but they learned that iodine could essentially be sprayed on table salt.
Iodised salt first became available in 1924. By the 1950s, more than 70 per cent of US households used iodised table salt. Bread and other foods were also fortified with iodine, and iodine deficiency became rare.
But diets changed. Processed foods now comprise a large part of the American diet, and though they contain a lot of salt, they are not iodised. Leading bread brands no longer add iodine. In the case of the 13-year-old boy, he has mild autism and was a fussy eater, mostly eating specific brands of bread and peanut butter.
For people who salt their food, the fashion now is to use kosher salt, Himalayan rock salt or other non-iodised products. “People have forgotten why there’s iodine in salt,” said Dr Elizabeth Pearce of Boston Medical Centre.
She is a leader in the Iodine Global Network, a non-governmental agency working to eliminate iodine deficiency disorders.
Though iodine consumption is falling, experts say most Americans still get enough in their diet. But doctors worry that is not the case for children.
Serrano-Gonzalez said she and her colleagues have seen four other cases in children at their clinic in Providence. “We’re concerned this may be increasing, especially in patients with restricted diets,” she said.
Associated Press
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How much iodine is enough?
According to the Food and Nutrition Board of the National Academies, the recommended dietary allowance (RDA) for iodine in the United States is about 120 micrograms for those between nine and 13 years old and 150 for teenagers above 14.
The Hong Kong Centre for Food Safety recommends eating a variety of foods high in iodine as part of a healthy, balanced diet. These include seaweed, seafood, egg, milk and dairy products.
It also advises taking less than five grams of salt daily and replacing non-iodised salt with iodised salt.
To keep the amount of iodine in your food as high as possible, consider preparing it by steaming or stir-frying it with a small amount of oil, cooking shellfish without removing the shells and adding salt that contains iodine just before serving.
Iodine can also be found in plant foods, such as cereal and grains, but the levels can vary based on where the food was grown.