Low Iodine Intake During Pregnancy Can Impact Baby’s Neurological Development

woman sitting on the bed holding vitamins in her hand

AsianVision / Getty Images

Key Takeaways

  • Iodine is crucial for healthy thyroid function.
  • During pregnancy, adequate iodine levels contribute to the baby's intellectual development.
  • A recent study found that many women of reproductive age are lacking iodine.

Adequate iodine intake during pregnancy is essential for the baby's intellectual development, but a recent study published in International Journal of Environmental Research and Public Health found that a growing number of young women have low levels of this important mineral.

This puts their children at an increased risk of impaired neurological conditions, warn researchers from the University of South Australia (UniSA).

“We carried out this study to get a better understanding of iodine status in women who consume plant-based diets, so we can then use this to improve fortification of plant-based foods and improve nutrition advice,” says UniSA research dietitian Jane Whitbread, B.Nut.Diet, one of the study authors.

About the Study 

The small pilot study compared iodine levels between 31 plant-based participants and 26 omnivores. Urine samples from the plant-based group showed iodine readings of 44 µg/L (micrograms per liter), compared to readings of 64 µg/L level in the meat-eating group. Neither group came close to the recommended 100 µg/L per day, as set by the World Health Organization.

“We were surprised at how low the iodine excretion was in the omnivore group, especially in those that consume pink salts which are not fortified with iodine,” Whitbread says. Participants from both groups who chose pink or Himalayan salt over iodized salt had iodine levels of only 23 µg/L on average. 

And it wasn’t only iodine that was in short supply. Calcium intake was poor in both groups, and dietary vitamin B12 and selenium was low in the plant-based group. “This was expected, as these nutrients are more concentrated or mostly found in animal-derived products,” Whitbread explains.

However, the plant-based group consumed higher levels of iron, magnesium, vitamin C, folate, and fiber than the omnivores, which Whitbread says is likely due to their increased legume, wholegrain, fruit, and vegetable intake. 

Boosting Iodine Levels 

Iodine maintains normal function of the thyroid, a gland in the base of the neck that regulates the hormones that control metabolism, heart rate, body temperature, and other core body functions. During pregnancy, getting enough iodine ensures that your baby also has healthy thyroid function.

If iodine is insufficient during pregnancy, it can also cause issues in growth and brain development, leading to neurocognitive impairment, says Colleen DeBoer, MS, RD, clinical nutrition manager at Northwestern Medicine Lake Forest Hospital in Illinois.

Colleen DeBoer, MS, RD

Taking a prenatal vitamin with iodine is the best way to ensure you’re getting adequate amounts of iodine.

— Colleen DeBoer, MS, RD

The NIH recommends 150 µg of iodine per day before pregnancy, 220 µg per day during pregnancy, and 290 µg per day while breastfeeding. Because the body doesn't produce iodine itself, you have to get it from your diet, says Vanessa Rissetto, registered dietitian and co-founder of Culina Health.

She recommends including foods that are natural sources of iodine, such as tuna, cod, other seafood such as shrimp, milk, yogurt, and cheese. You can also use iodized salt for cooking. 

You could be lacking in iodine and not know it, but some symptoms of iodine deficiency include an enlarged thyroid, fatigue, constipation, and sensitivity to cold temperatures, Rissetto adds. 

What This Means For You

If you think you might be lacking in iodine, check in with your doctor to chat about any symptoms you might have. A nutritionist can advise you on the foods you should be eating to boost your iodine intake. Note that if you have a known thyroid condition, you should always check with your doctor before increasing your iodine levels.

Not everybody eats foods that contain iodine—and during pregnancy, this might be even more of an issue if you're having aversions to certain foods. But there's another option, and it's a really simple one. “Taking a prenatal vitamin with iodine is the best way to ensure you’re getting adequate amounts of iodine,” says DeBoer. 

As well as a campaign to raise awareness about the importance of iodine in the diet, especially for women in their reproductive years, the researchers recommended that both new salts and plant milks be fortified with iodine. “This would ensure that a range of commonly consumed foods continue to be a source of iodine,” Whitbread says. 

3 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Whitbread JS, Murphy KJ, Clifton PM, Keogh JB. Iodine excretion and intake in women of reproductive age in South Australia eating plant-based and omnivore diets: a pilot study. Int J Environ Res Public Health. 2021 Mar 29;18(7):3547. doi:10.3390/ijerph18073547

  2. World Health Organization. Iodine deficiency.

  3. National Institutes of Health. Iodine.  

By Claire Gillespie
Claire Gillespie is a freelance writer specializing in mental health. She’s written for The Washington Post, Vice, Health, Women’s Health, SELF, The Huffington Post, and many more. Claire is passionate about raising awareness for mental health issues and helping people experiencing them not feel so alone.