Iodine is a mineral that 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 childhood. If pregnant women don’t get enough iodine, the deficiency can cause their babies to be born with intellectual disabilities. An iodine-deficient fetus may experience growth retardation, delayed sexual development, a lower-than-average IQ, and an inability to think clearly. We do not produce iodine, so we must eat foods rich in iodine to keep our bodies adequately supplied.
The history of iodine is interesting.
Records have been found in early Chinese medical documents, some as early as 3600 BC. C., who report a decrease in the size of the patients’ goiter after receiving burnt seaweed and sea sponge remedies. Iodine as a unique mineral had not yet been identified, but these iodine-rich remedies were known to be effective. Its use to treat goiter became a worldwide norm, documented in writings in later centuries by other early physicians, 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 the components needed to make gunpowder, extracting sodium salts, and while treating algae ash with sulfuric acid, he noticed a purple vapour. Other scientists began to study the vapor, and in 1813 a scientific paper was published that officially identified iodine as a new element. Ioeides, a Greek word, translates as ‘purple in color’.
Then a doctor in Switzerland published an article describing his successful use of grains of iodine, administered (after being dissolved in alcohol) orally, to decrease the size of goiters in his patients. The link between iodine deficiency and goiter was raised, studied, and then definitively identified by the French chemist Adolphe Chatin and Eugen Baumann, respectively.
There used to be a significant problem with iodine deficiency in the United States. Before the 1920s, part of the country was known by an unflattering nickname: the “goiter belt.” In the Great Lakes, Appalachian and Northwest regions of the country, 26 to 70 percent of children had ‘clinically apparent goiter’, also known as clearly visible goiter. Within the general population, the prevalence of goiter reached 64 percent in certain areas of Michigan.
In 1917, an Ohio physician, David Marine, and his team embarked on an experiment. They gave 2,100 children iodine supplementation and reported their success. In the children who received iodine, the rate of goiter was reduced to less than two percent. In the untreated group, the goiter rate was around 25 percent.
In 1922, at a thyroid symposium organized by the Michigan State Medical Society, a pediatrician named David Cowie proposed that the United States should start an iodized salt initiative to make simple goiters a thing of the past. Two years later, iodized salt first appeared 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% of households in the United States use iodized salt exclusively, even though it is available to more than 90 %.
The amount of iodine we need each day differs according to age:
Birth to 6 months – 110 micrograms
Babies 7-12 months – 130mcg
Children from 1 to 8 years old – 90 micrograms
Children from 9 to 13 years old – 120 micrograms
Children from 14 to 18 years old – 150mcg
Adults – 150mcg
pregnant women and adolescents – 220 micrograms
The 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 could be at play:
Preserve. When the thyroid does not have enough iodine, it begins to enlarge. Your thyroid gland is shaped like a butterfly and is located at the base of your neck, in front, below your Adam’s apple. Goiters can be a general enlargement of the thyroid, or goiters can form 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. It makes sense: the thyroid needs iodine to do its job, so without enough iodine, the thyroid can’t function properly. Symptoms may include fatigue, muscle weakness, constipation, dry skin, sensitivity to cold (more than normal), increased sleepiness, weight gain, depression, and slowness in movement and thinking.
Foods rich (and poor) in iodine
Foods rich in iodine include dairy products (with a caveat: only if the livestock received iodine supplements), fish and shellfish, eggs, and seaweed, such as nori or seaweed. Foods with very little iodine are commercially baked bread that has not been fortified and most fruits and vegetables. The iodine content in meats depends on how much iodine the animals ate.
Here are some foods, their estimated iodine content, and the percent Daily Value (DV) in micrograms (mcg) they contain:
- cooked oysters, 3 oz. – 93 mcg or 62 percent of DV
- greek yogurt¾ cup, plain: 87 mcg or 58 percent of the DV
- enriched white bread (made with iodate dough conditioner), 2 slices: 320 MCG or 213 percent DV
- enriched wheat bread (made with iodate dough conditioner), 2 slices: 309 mcg or 206 percent DV
- Seaweed (nori) 2 dry tablespoons – 116 mcg, or 77 percent DV
- Cooked fish sticks3 ounces – 58 mcg or 39 percent DV
- Baked cod3 ounces: 158 mcg or 213 percent DV
- fat free milkone cup: 85 mcg or 57 percent DV
- iodized table saltquarter teaspoon: 76 mcg or 51 percent DV
- a hard boiled egg– 26 mcg or 17 percent DV
- cooked shrimp3 ounces – 13 mcg or 9 percent DV
- Beef (baboon) – 3 mcg or 2 percent DV
- Chicken breast3 ounces – 2 mcg or 1 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
Zero iodine foods include:
- Green peas
- Enriched dry pasta
- Soy sauce
- Broad beans
- egg whites
- Canned, fresh or dried beans
- unsalted peanut butter
- fresh raw vegetables
People identified as having iodine deficiencies may add iodine-rich foods to their diets or may be prescribed iodine supplements or sometimes thyroid hormone supplements.
Do you think you can be low? Talk to your doctor about your concerns.