Subclinical Hypothyroidism in Korean Preterm Infants Associated with High Levels of Iodine in Breast Milk

Abstract

Excessive iodine intake from BM contributed to subclinical hypothyroidism in these preterm Korean infants.

Dietary Factors and the Risk of Thyroid Diseases: A Review

“…24) In Korea, the frequency of subclinical hypothyroidism in preterm infants born at 34 weeks of gestation or less was higher with high iodine intake from breast milk than with low iodine intake from breast milk both 3 weeks (p=0.033) and 6 weeks (p=0.032) after birth. 25) In …”

Alimentos ricos en ácidos grasos v-3 libres de contaminantes y aptos para vegetarianos, y su importancia en el desarrollo neurológico normal

“…Contenido de ácidos grasos v-3 en algunos vegetales y aceites vegetales terrestres (g/100 g) 79 , es importante controlar su ingestión, especialmente en mujeres embarazadas. Se ha descrito que una ingestión elevada de yodo mediante la leche materna puede causar hipotiroidismo subclínico en niños de 3-6 semanas de edad 87 . Se cree que existen unas 30.000 especies de algas, microalgas marinas o fitoplancton, pero para producir grasas se han estudiado y analizado muy pocas 88 .…”

High Iodine Content of Korean Seaweed Soup: A Health Risk for Lactating Women and Their Infants?

“…Korean and many Korean-American women traditionally consume brown seaweed soup (Undaria pinnatifida) daily during the early postpartum period (Supplementary Data; Supplementary Data are available online at www .liebertonline.com/thy) (1). This tradition is maintained among Korean and Korean-American women such that their breast milk iodine correlates strongly with frequency and quantity of seaweed soup consumption (2,3). As the iodine content of this soup has not been reported, we randomly selected 10 brands of dried brown seaweed from Korea and China available in the United States.…”

“…Our findings indicate that this constitutes an average iodine intake of at least 1400 mg/day in the first postpartum week based solely on 250 mL seaweed soup broth three times daily, and at least 5000 mg/day if the entire contents of each serving are consumed (broth and seaweed). High levels of breast milk iodine values in Korean postpartum women have been reported (2,3). Depending on quantity and frequency of intake, postpartum women who consume Korean seaweed soup may have daily iodine intakes and breast milk iodine concentrations that far exceed the WHO and IOM upper limits.…”

“…However, the effects of high iodine intake are dependent on several factors, including iodine status (i.e., degree and duration of iodine deficiency or sufficiency) before excess iodine exposure, as well as any preexisting thyroid autoimmunity, thyroid dysfunction, and/or thyroid nodularity. Chung et al reported subclinical hypothyroidism in preterm Korean infants exposed to high iodine content in breast milk (2). Additionally, cases of iodine-induced neonatal hypothyroidism due to maternal seaweed consumption were reported in Australia.…”