Why is most salt "iodized" in the US?

Sea salt is all the rage these days—and why not? It’s trendy, it sounds cool, and it tastes great. I’ll admit, I love my pink Himalayan sea salt too. But there’s an important reason why salt was iodized in the first place, and it’s worth revisiting—especially in an era where fancy salts have taken over our spice racks.

What is Iodine?

Iodine is a mineral found in the earth's crust and some foods. It’s essential for the production of thyroid hormones, which regulate metabolism and other critical functions in the body. These hormones are also vital for proper brain and bone development during pregnancy and infancy, making iodine especially important for pregnant women and infants.

Why Was Salt Iodized?

Before the 1920s, iodine deficiency was a significant public health issue in the United States. It led to widespread goiters(enlarged thyroid glands) and symptoms of hypothyroidism. To combat this, the U.S. introduced iodized salt in the 1920s, significantly improving iodine levels across the population.

Fast forward to today: the growing popularity of non-iodized salts, like sea salt, kosher salt, and Himalayan salt, has raised concerns about iodine deficiency—particularly among pregnant and lactating women, as well as infants. These groups are most vulnerable to the effects of inadequate iodine intake.

Are You Getting Enough?

Iodine deficiency is rare in many developed countries but can still occur, especially for those who don’t use iodized salt or consume iodine-rich foods. Here are some signs to watch for that may indicate low iodine levels:

• Weakness and fatigue

• Sensitivity to cold

• Constipation

• Weight gain

• Depression

• Dry skin and hair

If you experience these symptoms, consider speaking with a healthcare provider to determine if iodine deficiency could be a factor.

Where Can You Get Iodine in Your Diet?

For vegans or plant-based eaters, iodine-rich sources include:

• Iodized salt: Look for "iodized" on the label. Just half a teaspoon provides the daily recommendation for adults.

• Sea vegetables:

  • Laver or nori (2 oz): ~3,000–6,000 μg of iodine (enough to last 20–40 days).

  • Dulse (2 oz): ~1,500–3,000 μg of iodine (enough for 10–20 days).

  • Wakame (2 oz): ~800–1,000 μg of iodine (enough for 5–7 days).

  • Kelp (2 oz): ~20,000–30,000 μg of iodine (enough for years—consume with caution).

• Multivitamins: Check the label to ensure iodine is included.

  
  

  Note: Animal products like fish and seafood (e.g., cod, tuna, shrimp) and dairy products (milk, yogurt, cheese) contain some iodine.

  
  

Why is Iodine So Important?

Iodine is critical for brain myelination during pregnancy and the early postpartum period. Inadequate iodine can impair brain development in the fetus and infant, leading to long-term cognitive issues.

Beyond pregnancy, iodine is essential for everyone because it supports thyroid function, which regulates metabolism, energy levels, and overall hormonal balance. Thyroid hormones are vital for growth, repair, and maintaining healthy organs and tissues throughout life.

• The World Health Organization (WHO) recommends 250 μg/day of iodine during pregnancy and lactation.

• The U.S. Institute of Medicine recommends slightly lower levels: 220 μg/day during pregnancy and 290 μg/dayduring lactation.

• For non-pregnant adults, the daily requirement is 150 μg/day to ensure proper thyroid hormone production and metabolic function.

Does Iodine Interact with Medications?

Yes, iodine can interact with certain medications, including:

• Anti-thyroid medications (e.g., methimazole): High iodine doses may suppress thyroid hormone production.

• ACE inhibitors (e.g., lisinopril, benazepril): Combining iodine with these medications can raise potassium levels dangerously.

• Potassium-sparing diuretics (e.g., spironolactone): Similar to ACE inhibitors, these can cause unsafe potassium levels when combined with iodine.

Always consult with your healthcare provider if you’re taking medications and considering iodine supplementation.

Meal Plan and Menu Items Rich in Iodine:

• Breakfast (Nori Avocado Toast): ~70 μg

• Morning Snack (Chia Smoothie with Iodized Salt): ~40 μg

• Lunch (Wakame Miso Soup): ~75 μg

• Afternoon Snack (Chickpeas with Dulse Flakes): ~50 μg

• Dinner (Quinoa and Veggie Bowl with Iodized Salt): ~40 μg

• Evening Snack (Brazil Nuts): ~50 μg

Total Iodine Intake: ~325 μg This exceeds the daily recommended intake for most adults (150–160 μg) but is well below the upper limit of 1,000 μg/day, making it safe and effective for ensuring adequate iodine levels.

How Much Iodized Salt Provides 150 μg of Iodine?

• To meet the daily iodine requirement of 150 μg:

  150 μg ÷ 45 μg per gram = ~3.3 grams of iodized salt.

This is approximately half a teaspoon of iodized salt (one teaspoon weighs about 6 grams).

Note: While iodized salt is a great source of iodine, be mindful of sodium intake. Excessive sodium can increase the risk of high blood pressure and other health issues. The American Heart Association recommends limiting sodium to 2,300 mg/day, about 1 teaspoon of salt from all dietary sources. Mixing iodized salt with other iodine-rich foods is a balanced approach.

Key Takeaways

Don’t be afraid of iodized salt—it was introduced for a reason: to prevent iodine deficiency and its associated health risks. By incorporating iodized salt into your daily routine, you’re likely to meet the recommended iodine intake without needing to worry about deficiency.

If you prefer specialty salts like sea salt or Himalayan salt, just be mindful to include iodine-rich foods, such as sea vegetables or fortified multivitamins, to ensure adequate intake.

With iodized salt as a convenient and effective option, you can enjoy flavorful meals and peace of mind, knowing you’re supporting your health with this essential nutrient.

References

• Leung AM, Braverman LE, Pearce EN. History of U.S. Iodine Fortification and Supplementation. Nutrients, 2012.