This Essential Mineral Has Declined By Up To 30% In Americans, Report Finds

No one's diet is perfect. There's always going to be things we're getting too much of (maybe sugar) and nutrients that we should be consuming more of (like omega-3s). The Centers for Disease Control and Prevention (CDC) recently assessed a range of nutritional biomarkers (measures that taken by a blood or urine test for example) to evaluate the country's nutritional status. It found that certain key nutrients are quite lacking in the average diet. The first is omega-3s (and we dive into that info here). Another is iodine.

The CDC's report analyzed blood and urine samples collected from thousands of Americans between 1999 and 2023 to better understand the nation's nutritional status. Unlike food surveys, these biomarker measurements provide an objective look at how much of a nutrient people actually have in their bodies.

When researchers looked at urinary iodine (a well-established marker of recent iodine intake) they found that median iodine concentrations have declined over time in several populations. One of the largest decreases was among women ages 20 to 39, whose median iodine levels dropped by roughly 30% over the study period. Similar downward trends were also observed in children and other adult age groups.

Your thyroid relies on iodine1 to produce hormones that help regulate everything from metabolism and energy production to body temperature and healthy growth and development. During pregnancy, iodine needs increase because these hormones also play an essential role in supporting a baby's brain and nervous system development.

The CDC report wasn't designed to determine why iodine status has declined, so it can't tell us exactly what's driving these trends. However, previous research points to these factors.

For starters, iodine isn't naturally abundant in most foods. Because it's concentrated in the ocean, seafood and seaweed are among the richest sources, while the amount found in crops depends largely on the iodine content of the soil they're were grown in. In many inland and mountainous regions, soils contain relatively little iodine, making it harder for foods grown there to contribute meaningful amounts.

Dietary habits have also shifted over time. Although iodized table salt has helped reduce iodine deficiency for decades, many people now choose Himalayan pink salt, sea salt, or kosher salt, which typically aren't fortified with iodine.

You can support your iodine levels by increasing intake of the iodine-rich foods mentioned above(seafood, seaweed, some dairy products, and eggs). However, a supplement can also be helpful.

When shopping, check the Supplement Facts label to make sure it includes iodine—ideally around 100% of the Daily Value (150 mcg), as not every formula does. While supplementation can help support healthy iodine intake, more isn't necessarily better.