May 27, 2014
News Review From Harvard Medical School -- Extra Iodide Urged for Pregnant Women
Many pregnant women don't get enough iodine, which is important for babies' brain development, a group of children's doctors says. The American Academy of Pediatrics (AAP) published the statement. It recommends that pregnant and breastfeeding women take supplements that contain potassium iodide. The thyroid uses iodine when it makes thyroid hormone. Among other functions, this hormone is critical for normal brain development. About one-third of pregnant U.S. women have at least a mild iodine deficiency, the policy statement says. Only about 15% of pregnant and breastfeeding women take supplements. The AAP recommends that they take a daily pill containing at least 150 micrograms of iodide. They also should use iodized table salt, the statement says. Total intake should be 290 to 1,100 micrograms a day. The AAP statement also warns about the chemical pollutants thiocyanate, nitrates and perchlorate. They can compete with iodide for transport into the thyroid and breast milk. Pregnant women are urged to avoid cigarette smoke. They also should avoid well water with high levels of nitrates, the AAP said. The journal Pediatrics published the statement. HealthDay News wrote about it May 26.
By Claire McCarthy, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
If you're pregnant, I have an important question for you: are you getting enough iodide?
It's not something we think about a lot, but we should, because iodide is really important. That's why the American Academy of Pediatrics has issued a new policy statement on iodine deficiency, pollutant chemicals and the thyroid. The journal Pediatrics just published the statement.
The thyroid gland needs iodine to work -- and it's pretty crucial that the thyroid gland work. It is key for our metabolism. In pregnant women, it's also essential for the brain development of the fetus. And babies who are exclusively breastfed need to get iodine from breast milk in order to keep the thyroid gland working and the brain developing normally.
Severe deficiencies in thyroid hormone lead to serious mental retardation and other brain problems. Milder deficiencies can lead to problems as well.
In 1924, iodine was added to table salt to be sure that everyone had enough iodine. But now, one-third of the pregnant women in the United States are at least marginally deficient in iodine. This worries doctors.
The problem is processed foods. Most of us eat more of them than we should. And while there is plenty of salt in most processed foods, it doesn't contain iodine. Food companies are reluctant to add iodine. They are afraid it will change the taste or other characteristics of processed foods.
It's not just the lack of iodine that can mess up the thyroid gland. The body uses something called the sodium iodine symporter to move iodine into thyroid cells, and also into breast milk. But the pollutants thiocyanate, nitrates and perchlorate compete with iodide in this process.
The most common source of thiocynate is tobacco smoke. Nitrates and perchlorate are found in drinking water, often in well water.
What Changes Can I Make Now?
Pregnant women need 290 micrograms of iodine every day. In order to be sure they get that much, it's recommended that they take a daily supplement that contains 150 micrograms of iodine. Currently, only 15% to 20% of pregnant women take a supplement that contains iodine.
If you are pregnant, talk to your doctor about which supplement is best for you.
It's also a good idea to use iodized salt. The amount of iodine can vary a bit, depending on how long the salt has been out, and the brand. However, about a half a teaspoon a day is generally enough. It's true that we don’t want people to consume a lot of sodium, and salt has sodium. But if you eat less processed food, and sprinkle your healthy, fresh foods with a tiny bit of iodized salt, you are better off in the long run.
As for the chemicals that can stop iodine from getting where it needs to be, pregnant women should stay away from tobacco smoke for all sorts of reasons. This is yet another reason. The Environmental Protection Agency put rules into place to limit perchlorate in 2011. If you drink well water, be sure to have it tested for perchlorates and nitrates.
What Can I Expect Looking to the Future?
I hope that people will pay attention to this clinical report and become more aware of the importance of iodine. I hope we also make the changes needed to be sure we are getting enough. The changes really are simple, and making them can make all the difference for the brain development of babies.