Complacency and misinformation are driving Americans to undo public health progress. In the developed world, relatively insulated from the dangers of disease, we’ve forgotten how we earned this privileged status. The quintessential case is vaccines. As afflictions like measles, mumps, polio, and whooping cough were banished from daily life to history books, more and more people decided they didn’t need to roll up their sleeves for a quick jab.
But vaccines aren’t the only the only public health advance Americans have started to turn their backs on. Doctors worry that we may now be witnessing the return of goiter, a swelling in the neck resulting from an enlarged thyroid gland. Why? Because we’ve stopped consuming enough iodine.
A century ago, an estimated 26 to 70 percent of children living in the northern United States had the condition. Goiter wasn’t merely unsightly, it indicated that the thyroid gland was not functioning properly. The organ produces hormones that regulate heart rate, body temperature, brain development, and energy levels. If it’s not functioning properly, you’re not functioning properly.
Nine in ten cases of goiter are caused by iodine deficiency. Iodine is an essential building block for the hormones the thyroid produces, so when it doesn’t get enough, it enlarges in an attempt to do more with less. Iodine deficiency drives an array of health problems. Most concerningly, it stunts physical growth and cognitive development. Fetuses of pregnant women who don’t consume enough iodine will not develop normally. Children who don’t get enough have significantly lower IQs and higher rates of ADHD.
A little over a century ago, a team of scientists in the Midwest realized that iodine deficiency was causing goiter, then ran trials to see if iodine supplementation could cure it. As a team of endocrinologists recounted in the journal Nutrients:
David Marine, a U.S. physician in Ohio, and his colleagues initiated an iodine prophylaxis program in over 2100 schoolgirls in 1917. Over the next few years, he and colleagues published a series of papers reporting a significantly decreased frequency of goiter in children treated with iodine (0.2%), compared to children who did not receive iodine supplementation (>25%).
Based on this resounding success, in 1924, food companies launched iodized salt in grocery stores. Over just a couple of decades, goiter and iodine deficiency were basically eliminated in the U.S. Fifty years later, the median concentration of iodine found in Americans’ urine exceeded 300 micrograms per liter (µg/L), comfortably exceeding the minimum recommended threshold of 100 µg/L.
But a problem solved all too often becomes a problem forgotten. Today, many Americans don’t know what the “iodized” of “iodized salt” means. Thinking iodized salt to be “processed” and “full of chemicals,” they instead purchase alternatives such as “natural” sea salt or pink-hued Himalayan salt, both of which contain little to no iodine. At the same time, food companies neglect to use iodized salt in the myriad processed foods that Americans consume. We also don’t eat enough foods that are naturally high in iodine, like dairy, seafood, seaweed, and eggs. As a result, a 2022 study found that American adults are, on average, at potential risk of iodine deficiency once again, with urine concentrations of just 116 µg/L.
Processed foods are widely vilified today, but people forget that fortified foods are processed foods, and they are undeniably beneficial. Without fortification and supplementation, more than half of humanity would not get enough of seven key vitamins and minerals, according to a report published in The Lancet in October of last year. The nutrient we’d be most short on? Iodine, at 68 percent of the global population.
As it is, thanks to iodization, only 30 percent of humanity is at risk of iodine deficiency. There’s no good reason for Americans to join that minority. So opt for the iodized salt at the store, and don’t be afraid to sprinkle some on your scrambled eggs.