Researchers urge awareness of dietary iodine intake in postpartum Korean-American women who consume brown seaweed soup

Written as a Letter to the Editor for the journal Thyroid and published online, the authors discuss the adverse effects of consuming excess amounts of iodine, which include iodine-induced hypothyroidism, thyrotoxicosis and goiter. Previous studies have shown that iodine content in breast milk of Korean lactating mothers has a strong correlation with the frequency and quantity of brown seaweed soup consumption.

"Traditionally, Korean and Korean-American women eat brown seaweed soup daily during their early postpartum period, yet they are not aware of risks associated with eating too much iodine-rich foods," said the lead author, Soo Rhee, MD, from the section of Endocrinology, Diabetes and Nutrition at BUSM.

The researchers randomly picked 10 different brands of brown seaweed available in the U.S. for their research. Utilizing the same recipe for each batch, the researchers measured the iodine concentration of the dry seaweed, the seaweed soup broth and the blended mixture of broth and solid soup. What they found were varied amounts of iodine in the soups based on where the seaweed was from and when it was harvested. Given the range of iodine content in the soup recipes, as well as previous research looking at daily brown seaweed soup consumption in postpartum Korean women, many of these women could potentially be ingesting more iodine than the World Health Organization and Institute of Medicine recommends.

The researchers conclude that additional studies need to be done to evaluate the potential adverse effects of long-term high dietary iodine consumption in Korean and Korean-American women and their infants. Additionally, the researchers recommend that health care providers be educated about Korean and Korean-American women dietary habits so that they can provide more guidance as to what their patients should be eating that is healthy for both the women and their infants.

The letter's co-authors, Lewis Braverman, MD, Sam Pino, Xuemei He, MD, and Elizabeth Pearce, MD, are all from BUSM's Endocrinology, Diabetes and Nutrition section.