Are you falling short in this mineral? It may surprise you.

Iodine: We’re Falling Short Again
Once iodized salt became available for Americans in 1924, per request of the government, thyroid-related issues resulting from iodine deficiency seemed to become a thing of the past. But, more recently, iodine concerns have cropped up again. A report, using data from the National Health and Nutrition Examination Survey and the National Children’s Study, found that urinary concentrations of iodine in 2009-2010 were significantly lower than in 2007-2008.

Why the drop in iodine levels? Salt used in processed foods is not typically iodized, and as Americans increasingly rely on these foods, intake of iodized salt is decreasing. Even iodized salt may not hold its promise: a 2008 study in Environmental Science & Technology found that over half of the 88 samples of salt analyzed did not contain the amount of iodine recommended by the Food and Drug Administration.

Iodine is important. Our bodies are not able to produce or store iodine, an essential element, and therefore, we must consume it on a regular basis. Once consumed, iodine molecules join together to produce the thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine), which are primarily responsible for thyroid function and metabolism. If your intake falls short, your body is unable to produce these hormones, which may result in hypothyroidism and its associated symptoms, such as fatigue, weight gain, cold intolerance, constipation, and even confusion. In the extreme, the thyroid gland may become enlarged, forming a goiter, as it attempts to capture more iodine from the bloodstream. Deficiency during pregnancy may have even more devastating effects, for it increases the risk of miscarriage as well as mental, physical, and behavioral concerns of the newborn.

Getting your iodine. Iodine can be found in a variety of foods, such as fish, dairy, eggs, and seaweed. However, the iodine content will vary greatly, depending on the soil in which the crops are grown, and where the animals—fish, cows, chicken—found their food. In fact, seaweed iodine levels can vary dramatically, depending on species and where it is harvested. One-quarter teaspoon of iodized salt provides about 70 micrograms of iodine.

Food (serving)	Iodine (mcg)*	Percent DV
Seaweed, whole or sheet (1 g)	16 to 2984	11% to 1989%
Cod, baked (3 oz)	99	66%
Yogurt, plain, low-fat (1 c)	75	50%
Iodized salt (1/4 tsp)	71	47%
Milk, reduced fat, 1 cup	56	37%
Bread, white, enriched, 2 slices	45	30%
Shrimp, 3 ounces	35	23%
Ice cream, chocolate (1/2 cup)	30	20 %
Egg (1 large)	24	16%

Source: NIH Office of Dietary Supplements; Note: g=gram, mcg=microgram, oz=ounce, DV=Daily Value, based on 2000 calories per day

*Because it is difficult to provide exact iodine content found in food, the values are approximate.

Getting enough

Iodine?

The iodine recommendation

for adults and adolescents

over 14 years of age is 150

micrograms (mcg) per

day; this recommendation

jumps to 220 mcg per day

for pregnant women.

This article was written by McKenzie for the November 2013 issue of Environmental Nutrition.