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How to Spot a Possible Iodine Deficiency and What to Do About it

03 November 2022

Iodine is a mineral our bodies need to make thyroid hormones. The body uses thyroid hormones, which are produced with the help of the iodine we consume, to control metabolism. Thyroid hormones also play a role in ensuring proper brain and bone development during pregnancy and infancy. If pregnant women do not get enough iodine, the deficiency can result in their babies being born with intellectual disabilities. An iodine-deficient fetus may experience stunted growth, delayed sexual development, lower-than-average IQ and an inability to think clearly. We don’t produce iodine, so we must eat foods rich in iodine in order to keep our bodies properly supplied.

The history of iodine is interesting. 

Records have been found in early Chinese medical documents, some from as early at 3600 BC, noting a decrease in patients’ goiter size after being given remedies of seaweed and burnt sea sponge. Iodine as a unique mineral had not yet been identified, but these remedies, rich in iodine, were known to be effective. Their use to treat goiters became a global norm, documented in writings in later centuries by other early medical practitioners including Hippocrates. 

Iodine got its name because of its violet color. It was discovered, albeit accidentally, in 1811. A French chemist, Bernard Courtois, was making components necessary to manufacture gunpowder – extracting sodium salts – and as he was treating seaweed ash with sulphuric acid he noticed a purple vapor. Other scientists began studying the vapor and in 1813, a scientific paper was published officially identifying iodine as a new element. Ioeides, a Greek word, translates as ‘violet-colored.’ 

Then, a doctor in Switzerland published an article outlining his successful use of iodine grains, administered (after being dissolved in alcohol) orally, to decrease the size of goiters in his patients. The link between lack of iodine and goiters was hypothesized, studied and then definitively identified by French chemist Adolphe Chatin and Eugen Baumann respectively.   

There used to be a significant problem with iodine deficiency in the United States. Prior to the 1920s, part of the country was known by a less-than-flattering nickname: the ‘goiter belt.’ In the Great Lakes, Appalachians and Northwestern regions of the country, 26 to 70 percent of children had ‘clinically apparent goiters,’ AKA goiters you could clearly see. Within the general population, the prevalence of goiters was as high as 64 percent in certain areas of Michigan.  

By 1917 a doctor in Ohio, David Marine, and his team embarked on an experiment. They gave 2100 children iodine supplements and reported their success. In the children given iodine, the frequency of goiters was reduced to less than two percent. In the untreated group, goiter rate hovered at greater than 25 percent.

In 1922, at a thyroid symposium hosted by the Michigan State Medical Society, a pediatrician named David Cowie proposed that the United States should begin an iodized salt initiative to make simple goiters a thing of the past. Two years later, iodized salt made its first appearance on Michigan grocery store shelves. It took decades of work to introduce iodized salt to the rest of the country and today an estimated 70-76 percent of households in the United States use iodized salt exclusively, though it’s available to more than 90 percent.

The amount of iodine we need each day differs by age:

Birth to 6 months – 110 mcg  

Infants 7-12 months – 130 mcg

Children aged 1-8 – 90 mcg

Children aged 9-13 – 120 mcg

Children aged 14-18 – 150 mcg

Adults – 150 mcg

Pregnant women and teens – 220 mcg

Symptoms of an iodine deficiency are all related to the effect the deficiency has on the thyroid and how it works. A couple of key indicators that iodine deficiency might be in play:

Goiter. When the thyroid doesn’t have enough iodine, it starts to enlarge. Your thyroid gland is shaped sort of like a butterfly, and it’s located at the base of your neck, in front, below the Adam’s apple. Goiters can be an overall enlargement of the thyroid, or goiters can be formed when irregular cell growth occurs, creating lumps or nodules. The most common symptom of a goiter is swelling. The most common cause worldwide is iodine deficiency, although that’s not common in the United States because most people use iodized salt.

Hypothyroidism (underactive thyroid). Iodine deficiency can cause hypothyroidism. Makes sense – the thyroid needs iodine to do its job, so without enough iodine, the thyroid can’t function correctly. Symptoms might include fatigue, muscle weakness, constipation, dry skin, cold sensitivity (more than usual), increased sleepiness, weight gain, depression and slow movements and thoughts.

Iodine rich (and poor) foods

Foods rich in iodine are dairy products (with a caveat – only if the cattle received iodine supplements), fish and seafoods, eggs and seaweed, like nori or kelp. Foods with very little iodine are commercially baked bread that hasn’t been enriched, and most fruits and vegetables. Iodine content in meats depends on how much iodine the animals ate.

Here are some foods, their estimated iodine content, and the percentage of your daily value (DV) in micrograms (mcg) they contain:

  • Cooked oysters, 3 oz. - 93 mcg or 62 percent of DV
  • Greek yogurt, ¾ cup, plain – 87 mcg or 58 percent of DV
  • Enriched white bread (made with iodate dough conditioner), 2 slices – 320 MCG, or 213 percent of DV
  • Enriched wheat bread (made with iodate dough conditioner), 2 slices – 309 mcg, or 206 percent of DV
  • Seaweed (nori) 2 tablespoons dried – 116 mcg, or 77 percent of DV
  • Cooked fish sticks, 3 ounces – 58 mcg or 39 percent DV
  • Baked cod, 3 ounces – 158 mcg or 213 percent DV
  • Nonfat milk, one cup – 85 mcg or 57 percent DV
  • Iodized table salt, quarter teaspoon – 76 mcg or 51 percent DV
  • One hard-boiled egg- 26 mcg or 17 percent DV
  • Cooked shrimp, 3 ounces – 13 mcg or 9 percent DV
  • Beef (chuck)- 3 mcg or 2 percent DV
  • Chicken breast, 3 ounces – 2 mcg or I percent DV
  • Bread (white or wheat) made without iodate dough conditioner, 2 slices – 1 mcg or 1 percent DV\
  • Sea salt (or any non-iodized salt), quarter teaspoon – less than 1 mcg or less than 1 percent DV 

Foods with zero iodine include:

  • Broccoli
  • Corn
  • Bananas
  • Green peas
  • Dried enriched pasta
  • Soy sauce
  • Lima beans
  • Egg whites
  • Fruits
  • Canned, fresh or dried beans
  • Unsalted peanut butter
  • Fresh raw vegetables

People identified as having iodine deficiencies can add iodine-rich foods to their diets or may be prescribed an iodine supplements or sometimes thyroid hormone supplements.

Think you may be low? Talk with your doctor about your concerns.

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