The Role of Iodine and Thiocynate in a Baby's Thyroid Health

How Mothers Can Ensure Their Baby Gets Enough Iodine

lactating, breastfeeding, nursing, new mother, perchlorate, thyroid, thiocyanate, iodine levels
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Iodine is an essential building block for thyroid hormone, and sufficient iodine levels are necessary for proper thyroid function and the resulting production of thyroid hormone. For women, thyroid hormone is crucial for fertility and a healthy pregnancy, as a developing fetus relies on its mother’s thyroid hormone, especially during the first trimester for proper neurological development.

Iodine Recommendations for Lactating Women

After birth, exclusively breastfed babies get iodine only through the mother’s breast milk. This means that healthy iodine levels in a lactating woman are essential to her newborn’s thyroid health and continued neurological development.

Recognizing the overriding importance of iodine, the dietary iodine requirements are significantly higher for lactating women. According to the Institute of Medicine, the Recommended Dietary Allowance (RDA) for iodine in lactating women is 290 μg per day, compared with 150 μg/day for nonpregnant adults of both genders.

Iodine levels are still considered sufficient in the overall population. Still, epidemiological studies such as the National Health and Nutrition Examination Survey (NHANES) have found that iodine levels have declined by half in the period from the early 1970s to the early 1990s. During this period, substandard iodine levels increased significantly, from four percent to 15 percent, in women of childbearing age.

As a result, researchers estimate that a subset of pregnant and lactating women have some degree of outright iodine deficiency, which can put their children at risk of developmental and cognitive problems.

What Causes Iodine Deficiency?

The iodine deficiency in women of childbearing age is, according to experts, the result of several factors, including:

  • Insufficient intake of dietary iodine, which typically comes from iodized salt and processed foods containing iodine and iodized salt.
  • Long-term environmental exposure to the chemical perchlorate, found in water supplies, and in produce irrigated with contaminated water.
  • Exposure to the chemical thiocyanate, found in cigarette smoke and goitrogenic/cruciferous vegetables, among other sources.

Iodine, Perchlorate, and Thiocyanate Levels

In late 2017, the journal Thyroid reported on a major study that looked at breastfeeding women in three regions: California, Massachusetts, and Ohio/Illinois. Over an eight-year period from 2008 to 2016, researchers evaluated the women’s iodine, perchlorate, and thiocyanate, measuring the levels using urine testing.

The researchers found:

  • The lactating women studied were generally iodine sufficient.
  • Among the lactating women, a significant subset had borderline levels of iodine.
  • Exposure to perchlorate and thiocyanate likely makes iodine less available in lactating women.
  • The iodine, perchlorate, and thiocyanate levels all significantly and positively correlated to each other in lactating women.

The researchers concluded that, given that more women of childbearing have an overt iodine deficiency as well as borderline iodine deficiency, and given the difficulty of limiting exposure to environmental perchlorate and thiocyanate, lactating women should focus on getting sufficient iodine as a way to protect their developing infants.

Tips for Lactating Mothers

If you are a breastfeeding mother, what does this mean for you, and what should you do?

First, you can ensure that you are getting sufficient iodine, ideally via supplementation. The American Thyroid Association recommends that all women receive dietary supplements containing 150 μg iodine daily during preconception, pregnancy, and while breastfeeding. They also recommend that all prenatal vitamins contain 150 μg of iodine. This position is also supported by the Endocrine Society and the American Academy of Pediatrics but has not yet been widely adopted in current clinical practice.

As of 2018, it’s estimated that 40 percent of all prenatal vitamins still do not include iodine, and studies have found that most obstetricians and midwives rarely recommended iodine-containing prenatal multivitamins for women planning pregnancy, pregnant women, or for lactating women. This means that it is up to you to seek out a brand of over-the-counter or prescription vitamin that contains the sufficient levels of iodine.

Second, if you smoke cigarettes, stop. In addition to the known health dangers of smoking, cigarette smoke is a significant source of thiocynate and this chemical clearly affects your iodine levels. If you are smoking while breastfeeding, this could interfere with your baby getting sufficient levels of iodine via your breast milk.  

Third, consider a reverse osmosis water filtration system for the water you use for cooking and drinking. These reverse osmosis filtering systems—in contrast to carbon-based filters such as the popular Brita or Pur water filters—can remove up to 95 percent of perchlorate from your water. Filtering your water can significantly reduce your overall exposure to this thyroid-damaging chemical.

Getting enough iodine, combining by taking action to reduce your exposure to thiocynate and perchlorate, can all help ensure that your baby gets the iodine he or she needs for healthy development.

Source:

Lee, Sun et.al. “Urinary Iodine, Perchlorate, and Thiocyanate Concentrations in U.S. Lactating Women.” Thyroid Journal. Volume 27,  Number 12, 2017. Mary Ann Liebert, Inc. DOI: 10.1089/thy.2017.0158.