Where do you find dietary sources of iodine?

  • 2 Minutes Read
Sue Heikkinen
Sue Heikkinen, MS, RDN, CDCES, BC-ADM, ACE-PT - Registered Dietitian Nutritionist and Certified Diabetes Care and Education Specialist

Did you know that one of the top dietary sources of iodine might be on your kitchen table? Learn why iodine is an essential mineral and the top dietary sources to include in your diet.

Dietary sources of iodine

Traditional dietary sources of iodine may conflict with healthier eating

Public health messages about using less salt have worked. In the United States, the salt shaker no longer accounts for the majority of sodium in the diet. Iodine is a trace mineral found naturally in some foods, as well as in fortified salt. Yet we’ve replaced sodium from iodized table salt with sodium from non-iodized salt in processed foods. This leaves us with the problem of high-sodium intake and possibly inadequate iodine.

What is the role of iodine in the body?

We must consume enough iodine for normal thyroid function critical for proper growth and development. In addition, adequate iodine is essential for a growing fetus and during early childhood. Iodine deficiency impairs brain development and, sadly, is a common cause of preventable mental disabilities and brain damage worldwide.

Iodine deficiency in adults can cause hypothyroidism (low thyroid function) and goiter (thyroid gland enlargement).

Dietary sources of iodine

Although iodine is a mineral abundant in the sea, foods from the sea contain varying amounts of iodine. Seaweed (e.g., kelp and nori), fish, and shellfish tend to be good dietary sources of iodine. Milk products and meat from animals grazing on grass from iodine-rich soil provide good sources of iodine, but not if the soil is iodine-poor. Mountainous areas far from the sea are notorious for being poor in iodine.

Given the importance of iodine for brain growth, it is troubling that the Centers for Disease Control (CDC) reported that iodine intake was the lowest (“slightly above insufficient intake”) among women of childbearing age in the United States.

Fortifying salt with iodine is a simple and cost-effective way to ensure adequate intake. This fortification is voluntary in the U.S., Canada, and many other countries. Most iodized salt products contain about 60-70 mcg of iodine per ¼ tsp serving, providing 40-45% of the RDA for adults who are not pregnant or breastfeeding.

Ironically, sea salt is NOT a good source of iodine despite being from the sea, and it typically is not fortified with iodine. Likewise, kosher salt is not fortified with iodine.

If you take a multivitamin-mineral supplement and are at risk for low iodine intake, consider an iodine-containing product.

Iodine content of select foods

Food Serving Iodine, mcg
Table salt, iodized ¼ tsp 76
Sea salt (non-iodized) ¼ tsp 1
Kosher salt (non-iodized) ¼ tsp <1
Pacific Cod, cooked 3 oz; 85 g 158
Milk, 2% 8 fl oz; 240 mL 97
Dried seaweed (nori) 2 sheets; 4 g 93
Egg 1 large 28
Tuna, light, canned in water 3 oz; 85 g 7

Iodine requirements

The Recommended Dietary Allowance (RDA) for iodine is 150 mcg for both men and women. The RDA is 220 mcg during pregnancy and 290 mcg for breastfeeding.

Before taking an iodine supplement, be aware that too much iodine can be harmful and may even impair thyroid function. The Tolerable Upper Limit (UL) for iodine is 1100 mcg for adult men and women, as well as during pregnancy and lactation.

Am I at risk for iodine deficiency?

If you eat a varied diet or use iodized salt regularly, it’s unlikely you are iodine deficient. However with a vegan diet (which does not include any animal products), you may be at risk for iodine deficiency. You may benefit from incorporating nori, iodine-fortified foods, or iodized salt into your diet or choosing an iodine-containing multivitamin/mineral.

If you are pregnant or planning to become pregnant, ask your healthcare provider how to get enough iodine. Unfortunately, not all prenatal vitamin-mineral supplements contain iodine.

Tracking iodine with MyNetDiary

You can track your iodine intake with a Premium subscription to MyNetDiary. We provide iodine data from the USDA database for common sources. However, many foods do not include iodine information in the USDA database or manufacturer-provided values. Given this missing data, your iodine intake may appear lower than it actually is.

Tip: Choose Staple Foods for the most detailed nutrient information.

Since iodized salt is a significant source of iodine, check that you are logging the correct salt type. The database food item “salt” refers to iodized salt since this is true of most table salt and is the type of salt specified in our Premium Recipes. If you use sea salt or kosher salt, log them as such. You may also "Copy & Customize" recipes to reflect the type and amount of salt you use.

With these tips and dietary sources of iodine to consider, you can tweak a meal or two each week and be on target with your iodine intake.

Still new to MyNetDiary? Learn more today by downloading the app for FREE.

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