by Reed Mangels, PhD, RD, FADA
Iodine is an essential nutrient. It’s needed for the thyroid gland to function properly and for normal physical growth and mental development.
Having appropriate levels of thyroid hormone in the first 3 years after birth is critically important for brain development. Worldwide, about 2 million children a year have stunted physical growth and cognitive impairment due to iodine deficiency (1).
Iodine deficiency was relatively common in the United States and in Europe until iodine began to be added to salt. However, processed foods are not typically made using iodized salt and people are using less salt these days and don’t always chose to use iodized salt.
Studies have reported that iodine intakes of vegans in several countries are lower than those of non-vegetarians (2, 3). Plant foods, including most fruits, nuts, and vegetables are low in iodine, although their iodine content varies depending on the soil they’re grown in and irrigation and fertilization practices. Sea vegetables supply iodine although the amount is variable so they cannot be relied on.
A recent case study points out the need for vegan children to have good sources of iodine. In this study (4), a 23-month old boy, who ate a vegan diet that did not include iodized salt, was found to have a very low concentration of thyroid hormone and an undetectable level of iodine in his blood.
He had been breastfed by his mother, who was vegan, until he was 16 months old. His mother took a prenatal vitamin-mineral supplement that apparently contained iodine since her iodine status was normal and the child did not develop iodine deficiency until he stopped breastfeeding.
Once the child’s iodine deficiency was discovered, he began taking a vitamin-mineral supplement that contained iodine and using iodized salt. His thyroid function returned to normal.
This case study demonstrates the importance of providing iodine to vegan infants and children. The American Thyroid Association recommends that pregnant and breastfeeding women take a prenatal supplement that contains at least 150 micrograms of iodine daily (5).
Once a vegan infant is not being breastfed by an iodine-sufficient mother or not using commercial infant formula, a supplement that contains iodine and/or iodized salt should be used.
The Recommended Dietary Allowance for 1-3 years old children is 90 micrograms of iodine per day. A rounded quarter teaspoon of iodized salt provides about this amount. Some brands of vegan children’s multivitamins contain iodine–check the label.
For more information about iodine, see the VeganHealth article, Iodine.
References
1. Syed S. Iodine and the “near eradication” of cretinism. Pediatrics 2015;135:594–6.
