Iodine: Are you getting enough?

August 18, 2012

Jonnell, Registered Dietitian

Chef Evan, one of our amazing cooking school chefs, normally recommends using sea salt instead of iodized salt because the flavor is much better.  He then often receives a question about what foods can be eaten to prevent iodine deficiency.  This is a great question, because iodine is essential to good health.  It is necessary for the production of thyroid hormones, which in turn are needed to regulate many functions in the body including protein synthesis and central nervous system development in fetuses and infants.  Iodine may also have an important role in immune function.

Before salt was iodized (each ¼ teaspoon iodized salt contains about 70 mcg iodine), iodine deficiency was fairly common in certain parts of the United States.  This is due to the fact that iodine content of foods reflects where the foods are grown and animals are grazed:  if the soil is low in iodine then the grain, vegetable, fruit, dairy or meat will also be low in iodine.  The latest health survey shows that, on average, most Americans are getting adequate iodine, but that the levels of iodine have decreased since the 1970s.

I personally prefer to use sea salt as I do agree with Chef Evan that it tastes better.  I also find that when flavoring dishes, I am satisfied with less sea salt.  If you also prefer to use a non-iodized salt, or if you are severely restricting your salt intake, take some simple steps to make sure you are meeting your iodine needs.  Consume foods typically found to be high in iodine on a regular basis such as seaweed, saltwater fish, shrimp, and dairy products such as yogurt and milk.  The amount of iodine in these foods vary, but three ounces of baked cod contains about 99 mcg iodine, 1 cup of plain yogurt contains about 75 mcg, and 1 cup milk contains about 56 mcg.  Seaweed is highly variable with a range of 16 to almost 2,000 mcg per sheet of seaweed (about 1 gram).  If these are not foods you consume on a regular basis consider taking a supplement.  Many multivitamin supplements contain iodine, so if you currently take a multivitamin supplement, check to see if it contains iodine.  If you are pregnant or breastfeeding, your need for iodine increases and you will want to make sure that your intake of iodine is adequate (many prenatal vitamins do contain iodine, but you will want to check your supplement).  Check the chart below for the recommended amounts of iodine.  Excessive iodine intake is rare, with the upper limit of safety ranging from 200 mcg for up to 6 months of age to 1,100 mcg per day for adults.  This is generally only seen in people taking excessive amounts of iodine supplements.

References:
Gropper SS, Smith JL, & Groff JL.  2009.  Advanced nutrition and human metabolism, 5th ed.  Belmont, CA:  Wadsworth Cengage Learning.
Centers for Disease Control and Prevention.  2010.  NCHS health E-stat:  Iodine level, United States, 2000.  Available at:  http://www.cdc.gov/nchs/data/hestat/iodine.htm
National Institutes of Health.  2011.  Dietary supplement fact sheet:  Iodine.  Available at:  http://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/