The United States is in danger of joining other countries, with people consuming too few iodine rich foods and having inadequate iodine levels. The United States may be facing increases in iodine deficiency disorders.
The major iodine source in the United States is from iodized salt. However, 53% of the United States iodized salt may not contain the recommended level, according to the study by Purnendu K. Dasgupta et al, “Iodine Nutrition: Iodine Content of Iodized Salt in the United States”, published in the 2008 Environmental Science & Technology journal, volume 42, issue 4.
How Much Iodine Prevents Iodine Deficiency?
According to their 2007 publication “Assessment of Iodine Deficiency Disorders and Monitoring their Elimination”, the United Nations Children's Fund (UNICEF), the International Council for the Control of Iodine Deficiency Disorders (ICCIDD) and the World Health Organisation (WHO) recommend the following daily iodine intake:
- Preschool children (aged 0 to 5 years old) – 90 micrograms (mcg)
- School children (aged 6 to 12 years old) – 120mcg
- Adolescents and adults (above 12 years old) – 150 mcg
- Pregnant and lactating women – 250mcg.
Foods with Iodine
Soil iodine content is generally very low. The oceans are the main iodine source; hence, seaweed is an excellent iodine rich food source of both inorganic and organic iodine. Dairy was once classed as a food high in iodine; however, this has changed since the use of chlorine in the milk production sanitisers instead of iodine, and the reduced use of iodine based-additives in livestock feed.
According to the “Iodine” section from the Linus Pauling Institute at Oregon State University, the following foods are iodine rich foods:
- Iodized salt and cow’s milk (varying amounts of iodine)
- Cod – 3 ounces or 85 grams* = 99mcg
- Shrimp – 3 ounces or 85 grams =35mcg
- Tuna, canned in oil – 3 ounces or 85 grams =17mcg
- Egg, boiled – 1 large=12mcg
- Navy beans, cooked – ½ cup=32mcg
- Potato with peel, baked – 1 medium=60mcg
- Turkey breast, baked – 3 ounces or 85 grams =34mcg
- Seaweed – ¼ ounce or 7 grams, dried – variable, may be up to 4,500mcg.
*A three-ounce serving (85 grams) of meat is about the size of a deck of cards.
Therefore, a meal of 85 grams of cod, and a baked potato filled with navy beans, without any added salt may equate to approximately 191 mcg of iodine. That is fine for an adult but is below the recommended iodine intake for pregnant and lactating women. Additionally, variations on these amounts exist because of different soil contents, so a guaranteed regular intake is not possible.
Even the iodine rich food source seaweed contains varying amounts.However, according to the 2004 study “Variability of iodine content in common commercially available edible seaweeds” by J. Teas et al, published in the Thyroid journal, nori, the seaweed most commonly used for sushi rolls, contains approximately 16mcg of iodine per gram. Processed kelp granules made from the seaweed Laminaria digitata contained 8165 mcg per gram, in this study.
Iodine Supplement Required in Pregnancy and Lactation
Reproductive women and infants are the most vulnerable to iodine deficiency. Pregnant and lactating women should consider an iodine supplement to increase their intake to the recommended level of 250mcg per day.
Iodine rich foods, other than iodized salt, must be eaten on a regular basis to ward off iodine deficiency. It is crucial that everyone is aware of the amount of iodine needed for health and wellbeing, that iodine rich foods are eaten and supplements are taken, if necessary.
References:
Patrick, L. (2008). Iodine: deficiency and therapeutic considerations. Altern Med Rev, 13(2), 116-127.
Dasgupta, P. K., Liu, Y., & Dyke, J. V. (2008). Iodine nutrition: iodine content of iodized salt in the United States. Environ Sci Technol, 42(4), 1315-1323.
Li, M., Eastman, C. J., Waite, K. V., Ma, G., Zacharin, M. R., Topliss, D. J., et al. (2006). Are Australian children iodine deficient? Results of the Australian National Iodine Nutrition Study. Med J Aust, 184(4), 165-169.
Melissa Peterson - Melissa Peterson is a naturopath specializing in nutrition education. Melissa has been writing and editing technical and patient-friendly ...
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