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[00:00.04]A century ago,

[00:02.68]iodine deficiency affected children

[00:06.24]across much of the United States.

[00:09.32]The problem mostly disappeared

[00:12.32]during the 1900s

[00:14.72]after iodine was added to common foods.

[00:18.68]But doctors are now seeing

[00:21.40]higher iodine deficiency rates.

[00:24.52]The rises are blamed on dietary changes

[00:28.80]and new food manufacturing methods.

[00:32.52]Iodine is an element found in seawater

[00:36.72]and in some soils

[00:38.88]— mostly in coastal areas.

[00:41.92]A French chemist accidentally

[00:44.52]discovered the substance in 1811.

[00:48.68]Iodine's name comes from a Greek word

[00:52.72]meaning violet-colored.

[00:55.20]Later in the 1800s,

[00:58.40]scientists began to understand

[01:01.72]that people need iodine

[01:04.16]to control their metabolism and stay healthy.

[01:08.20]The element is also important

[01:11.16]for a child's brain development.

[01:14.00]One sign of iodine deficiency

[01:17.64]is an increase in size,

[01:20.40]or swelling, of the neck.

[01:23.04]This growth in the neck is known as a goiter.

[01:27.88]It can appear when the thyroid gland

[01:31.64]grows to make up for too little iodine

[01:35.28]to produce hormones

[01:36.96]that control certain body processes.

[01:40.36]In the early 1900s,

[01:43.28]goiters were commonly seen in children

[01:46.40]in some parts of the United States.

[01:49.80]Some of the children showed other symptoms

[01:53.36]in addition to goiters.

[01:55.52]These included being smaller

[01:58.12]or experiencing deafness.

[02:00.88]In the past, public health experts realized

[02:05.08]they could not solve the iodine deficiency problem

[02:09.16]by feeding everyone seaweed and seafood.

[02:13.08]But they learned iodine

[02:15.68]can be included with table salt.

[02:18.92]This form of salt, known as iodized salt,

[02:23.92]first became available in 1924.

[02:28.36]By the 1950s, more than 70 percent

[02:33.12]of U.S. households used iodized table salt.

[02:38.20]Bread and some other foods also had iodine.

[02:43.28]As a result, iodine deficiency

[02:46.68]in the U.S. became rare.

[02:49.48]But diets have changed over the years.

[02:53.64]Processed foods now make up

[02:56.24]a large part of the American diet.

[02:59.88]Although these foods contain a lot of salt,

[03:03.96]it is not iodized.

[03:06.64]Leading bread makers also no longer add iodine.

[03:11.60]And for people who do salt their food,

[03:15.08]it is popular now to use kosher salt,

[03:18.60]Himalayan rock salt or other products

[03:22.40]that do not contain iodine.

[03:25.32]"People have forgotten

[03:27.16]why there's iodine in salt,"

[03:29.60]said Dr. Elizabeth Pearce

[03:32.16]of Boston Medical Center.

[03:34.72]She is a leader in the Iodine Global Network,

[03:39.36]a nongovernmental agency

[03:41.88]working to end conditions

[03:44.04]linked to iodine deficiency.

[03:46.96]Pearce noted there had been a reported

[03:50.44]50 percent drop in U.S. iodine levels

[03:54.44]studied during the 1970s through the 1990s.

[03:59.92]While most Americans

[04:01.92]are getting enough iodine through diet,

[04:04.88]doctors worry this is not the case

[04:08.16]for women and children

[04:10.32]– the two groups most likely to be hurt

[04:13.52]by iodine deficiency.

[04:15.84]The American Academy of Pediatrics

[04:19.36]and other medical groups

[04:21.32]advise that all pregnant and breastfeeding women

[04:25.60]get 150 micrograms of iodine each day.

[04:31.60]In the last 15 years or so,

[04:34.96]U.S. researchers have increasingly reported

[04:39.04]seeing mild iodine deficiency in pregnant women.

[04:43.84]A Michigan State University study

[04:47.28]of about 460 pregnant women

[04:51.08]found about 25 percent of them

[04:54.84]were not getting enough.

[04:56.72]That study's lead writer, Jean Kerver,

[05:00.72]noted that many vitamins for pregnant women

[05:04.68]do not contain iodine.

[05:07.60]As a result, doctors suggest that pregnant

[05:11.24]or breastfeeding women check labels

[05:14.16]to make sure the vitamins

[05:16.20]or supplements they take have iodine.

[05:19.76]Some studies have linked

[05:22.00]even mild iodine deficiency

[05:24.88]to a lower score on an intelligence test

[05:28.96]known as an intelligence quotient (IQ) test.

[05:34.36]But experts say

[05:36.36]there has not yet been enough research

[05:39.28]to establish exactly how the U.S. population

[05:43.76]is being affected by iodine deficiency.

[05:47.60]Dr. Monica Serrano-Gonzalez

[05:50.64]of Brown University said she and other doctors

[05:55.28]had seen five cases of iodine deficiency in children

[06:00.32]visiting a local health center

[06:02.88]in Providence, Rhode Island.

[06:05.04]"We're concerned this may be increasing,

[06:08.56]especially in patients with restricted diets."

[06:12.60]Serrano-Gonzalez called for increasing

[06:16.12]publicity about the problem

[06:18.60]in order to prevent it from getting worse.

[06:22.32]She said, "This needs to be on people's radar."

[06:27.52]I'm John Russell.

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Words in This Story

deficiency – n. a shortage of substances that are important or necessary for health

metabolism – n. all the chemical processes in the human body, especially the ones that use food

symptom – n. a physical feeling or problem that shows a person has a particular disease

label– n. written or printed material placed on a product to give more information about its contents