Iodine during the prenatal period is necessary for the mother and infant’s health. Prenatal and lactation needs for iodine are increased and current recommendations and screening may not be sufficient to provide both the baby and mom what they need for optimal health.
Many women may not get the iodine that they need for their own body and the growing fetus or may become depleted during lactation. (1) Each additional pregnancy can leave the woman even lower in iodine. Woman with many pregnancies may have more of a risk for having a child with congenital hypothyroidism at birth. Low iodine prenatally may also add to risk for autism or schizophrenia later in the child’s life.
Current recommendations for iodine by international agencies may be too low for pregnancy, lactation and for newborns. (1) A review team has recommendations for an increase in iodine supplementation – 250-300 micrograms of iodine daily for pregnancy and lactation and 90 micrograms for newborns. The team also recommends increasing the screening range for urinary iodine considered optimal to 150-230 micrograms of iodine. (1) Less iodine is excreted in the urine when the body is depleted.
A study based in Hong Kong also suggests that urinary iodine levels may not be an accurate test for assessing adequacy of iodine intake by lactating women as an indicator suggesting their breast milk would supply recommended iodine levels for their infants. (3)
“The most recent guidelines issued by the American Thyroid Association (73) suggested that all pregnant women should ingest ~250 μg iodine daily, and women who are planning pregnancy or are currently pregnant, should add to their diet a daily oral supplement that contains 150 μg of iodine.” May 21, 2020 (7)
*This was an unfinished older post, so I wanted to check if the recommendations have been updated.
Pregnancy and the neonatal period are higher risk stages for iodine deficiency t occur because the thyroid stimulating hormone (TSH) and thyroxine levels are modulated more than in other stages of the lifespan. TSH tends to be elevated more than normal and thyroxine decreased. Checking newborns for elevated TSH would be a biomarker for iodine deficiency. (1) When adequate iodine is provided promptly, the mental retardation associated with congenital hypothyroidism may be preventable. Treating with Synthroid alone would not help enough. All the glands of the body need iodine, not just the thyroid gland. If it is low, it means everything else in the body is even more depleted as the thyroid gets preferential use.
Re pregnant women and neonates: “…their serum thyroid-stimulating hormone (TSH) and thyroxine are increased and decreased, respectively, for degrees of ID that do not seem to affect thyroid function in the general population. Systematic neonatal thyroid screening using primary TSH could be the most sensitive indicator to monitor the process of ID control.” (1) *ID = iodine deficiency.
Conclusions from a study based in Thailand included the finding that heel prick blood at three days old was not as accurate as a sample from the umbilical cord sera for screening TSH levels in the newborn. (4)
Women become more depleted in iodine with each pregnancy and lactation stage of their lives. Infants seem to also get preferential use of iodine from the mother’s body stores. A study based in China found lower iodine levels in urban and rural prenatal and lactating women compared to the iodine levels of infants and school aged children living in the regions. The presence of goiter was low in all women (2.0%) but was more common in prenatal women (2.7%) than in lactating women or for all women combined. (2) Mammary glands also can use more iodine from maternal stores for breast milk production due to an increased activity of the iodine symporter/mineral channel. Low intake of iodine will lead to lower levels of iodine in the breast milk. (5)
“In areas of iodine sufficiency breast milk iodine concentration should be in the range of 100-150 microg/dl. Studies from France, Germany, Belgium, Sweden, Spain, Italy, Denmark, Thailand and Zaire have shown breast milk concentrations of < 100 microg/l. Adequate levels of iodine in breast milk have been reported from Iran, China, USA and some parts of Europe.” (5)
This information about maternal and neonatal preferential uptake of iodine suggests that iodine is VERY IMPORTANT for infant development. ←Noteworthy.
Being iodine deficient can equate to a drop in Intelligence Quotient (IQ) of up to 15 points. Supplementation can improve cognitive ability if started early for neonates or if the low iodine didn’t begin in infancy. (6)
“The intelligence damage of children exposed to severe ID [iodine deficiency] was profound, demonstrated by 12.45 IQ points loss and they recovered 8.7 IQ points with iodine supplementation or IS [iodine sufficiency] before and during pregnancy. Iodine supplementation before and during pregnancy to women living in severe ID areas could prevent their children from intelligence deficit. This effect becomes evident in children born 3.5 years after the iodine supplementation program was introduced.” (6)
Infants who are born low in iodine tend to grow very slowly, in proportion, but tiny. Shorter, narrower, lighter, less muscle mass, than if they had been sufficient in iodine. The appearance has been described as elfin and can be very cute as a child, however what might their full potential have been if mom had had enough iodine? More to point – why are low iodine thyroid conditions only treated with Synthroid and rarely with extra iodine? That is standard for anyone with hypotthyroidism – totally ignore the need for iodine by every other gland in the body.
Buyer be very wary of “health care professionals” – they may just be following standard protocols and seeking more information may be life improving.
Food sources of iodine: Eating adequate seaweed and seafood is the traditional source of iodine in many areas of the world. Seaweed species vary in iodine content, and it can vary within species. Supplements of seaweed for iodine use should be tested batch by batch for iodine content of the seaweed if the company is reputable. Other crops grown near the ocean tend to have higher levels of iodine than crops grown inland, which makes coconut a fairly good iodine source.
Some plants uptake iodine preferentially such as rhubarb, making it a vegetable high in iodine. It also has other medicinal benefits. This person really loved Siberian rhubarb for perimenopause, so I will let her tell you about it: (indigonaturals.net) There may be a product for sale, I am not affiliated. It is a thorough article on the intricacies of estrogen receptors.
The recommendations for iodine intake across the lifespan, may also be too low for everyone, when the competition of halides in the water and food supply is considered. Iodine can be replaced by bromide or fluoride or chloride in thyroid hormone, but the resulting hormone is then dysfunctional. Lab tests would show “normal” levels. Symptoms of hypothyroidism may be present while lab tests show the presence of a normal amount of T3 and T4 that may not have three atoms of iodine or four atoms of iodine. Instead, it might have some atoms of fluoride, bromide or chloride if the body was low in iodine and had plenty of the other halides present.
More information about iodine and selenium food sources, and the issue of halides in hypothyroidism is on page G9. Iodine & Thyroid. (effectivecare.info)
Selenium is also needed for the enzyme that breaks down excess thyroid hormone. Two Brazil nuts per day provides the typical goal used in alternative treatment – 200 micrograms of selenium per day. Selenium is not readily available in many foods and checking your one-a-day or Trace Mineral supplement mix for it would be a good idea as Brazil nuts can be expensive or hard to find.
**Addition, off-topic from iodine – I went back to the perimenopause article, (indigonaturals.net), and have found a biological difference between males and females – females may have – drumroll – more bliss – more of the THC equivalent endocannabinoid: anandamide.
“Despite these differences, FAAH inhibitors retain anxiolytic- and antidepressant-like effects in ovariectomized female rats . Interestingly, however, anxiolytic- and antidepressant-like effects produced by estradiol administration are attenuated by CB1R blockade , whereas estradiol administration increases AEA levels  or AEA signaling , possibly via downregulation of FAAH* driven by an estrogen response element on the FAAH gene that suppresses FAAH transcription when bound by estrogen.”
Goodness, let’s decipher that.
Basically, estradiol exerts its antidepressant and anti-anxiety effects by boosting anandamide. [*FAAH is an enzyme that breaks down cannabinoids.] In fact, they were able to block estradiol’s effect on depression and anxiety by blocking CB (endocannabinoid) receptors!
This means, the key to estradiol’s control of mood is…the endocannabinoid system and anandamide in particular!
By the way, this was a sex dependent effect…only women used this pathway in other experiments: Remarkably, this effect of E2 [estradiol] is sex specific, occurring in females but not in males.
Can we all agree that irritability is the opposite of bliss? (indigonaturals.net)
Yes, I can agree that irritability is the opposite of bliss – PMS history and genetic inability to make anandamide has left me familiar with irritability, also those around me – sorry. I would try to go to my office during PMS week and warn staff that I was having a cranky day – paperwork catch up day.
*In the modern era of trans gender hormone use, it is also interesting because the DNA male body might not be as blissful/peaceful even with estradiol use as someone with a DNA female body because the estrogen receptors would likely still respond as a male. If you paint a barn red, it doesn’t become a fire engine. Self-acceptance is a goal of maturing – we all have flaws and aging adds changes to those old familiar flaws.
Chocolate and Pregnancy – moderation/common sense – it is a nutrient rich food, hold the sugar and bad fats.
Chocolate is the richest commonly used food with some cannabinoid content – but not much for the calorie ratio. Bliss but not in a dose large enough for someone with a gene difference in ability to make endocannabinoids.
Cannabinoids are needed in pregnancy and lactation and chocolate is not that high in caffeine or theobromine that chocolate needs to be avoided (a frequent recommendation for pregnancy that I don’t agree with). Moderation on the calories, use of dark cocoa powder in a low sugar product would provide a variety of phytonutrients with anti-inflammatory benefits.
Disclaimer: Opinions are my own and the information is provided for educational purposes within the guidelines of fair use. While I am a Registered Dietitian this information is not intended to provide individual health guidance. Please see a health professional for individual health care purposes.
- Delange F., Iodine requirements during pregnancy, lactation and the neonatal period and indicators of optimal iodine nutrition. Public Health Nutr. 2007 Dec;10(12A):1571-80; discussion 1581-3. doi: 10.1017/S1368980007360941. http://www.ncbi.nlm.nih.gov/pubmed/18053281
- Yan YQ, et al., Attention to the hiding iodine deficiency in pregnant and lactating women and lactating women after universal salt iodization: A multi-community study in China. J Endocrinol Invest. 2005 Jun;28(6):547-53. http://www.ncbi.nlm.nih.gov/pubmed/16117197
- Kung AW., Iodine nutrition of pregnant and lactating women in Hong Kong, where intake is of borderline sufficiency. Public Health Nutr. 2007 Dec;10(12A):1600-1. doi: 10.1017/S1368980007360989. http://www.ncbi.nlm.nih.gov/pubmed/18053285
- Rajatanavin R., Iodine deficiency in pregnant women and neonates in Thailand., Public Health Nutr. 2007 Dec;10(12A):1602-5. doi: 10.1017/S1368980007360990. http://www.ncbi.nlm.nih.gov/pubmed/18053286
- Azizi F1, Smyth P., Breastfeeding and maternal and infant iodine nutrition. Clin Endocrinol (Oxf). 2009 May;70(5):803-9. doi: 10.1111/j.1365-2265.2008.03442.x. Epub 2008 Oct 6. http://www.ncbi.nlm.nih.gov/pubmed/19178515
- The effects of iodine on intelligence in children: a meta-analysis of studies conducted in China. Asia Pac J Clin Nutr. 2005;14(1):32-42. http://www.ncbi.nlm.nih.gov/pubmed/15734706
- Toloza FJK, Motahari H, Maraka S, Consequences of Severe Iodine Deficiency in Pregnancy: Evidence in Humans, MINI REVIEW article, Front. Endocrinol., 19 June 2020, Sec. Thyroid Endocrinology, https://doi.org/10.3389/fendo.2020.00409, https://www.frontiersin.org/articles/10.3389/fendo.2020.00409/full