Is Seaweed Soup Detrimental to Mothers and Newborns?

On birthdays, many South Koreans eat seaweed soup in the morning. After giving birth, mothers eat this brownish translucent broth swimming with seaweed, believing the nutrients will boost postnatal recovery.

But recently, an Australian study has been circulating in South Korean media, warning that miyeokguk may not be so healthy after all.

“There is no scientific evidence that drinking seaweed soup increases a mother’s breastmilk supply. In fact there is evidence it can be harmful to your baby,” Top News, a Korean-language online news outlet based in Australia reported, quoting a study from the New South Wales (NSW) health department.

The initial NSW report on seaweed soup came out in 2011, but it’s starting to make the rounds in South Korea again, after local media have picked up on the recent Top News report. Esther Au, a Public Affairs Advisor at NSW Ministry of Health, told Korea Exposé that NSW has not released anything about seaweed soup since 2011.

A common reason for eating seaweed soup before and after childbirth is because miyeokguk is rich in iodine, an essential component of thyroid hormones. Because thyroid hormone deficiency can impede the physical and intellectual development of both fetuses and newborns, iodine is added to salt in some places where local diets have low levels of naturally occurring iodine.

But too much of anything can be bad for you; the old NSW study highlighted the risk that excessive consumption of seaweed can cause thyroid malfunction.

One bowl of seaweed soup contains approximately 1,705 micrograms of iodine, almost six times the daily recommended iodine intake for breastfeeding women (290 micrograms according to the U.S. National Institutes of Health). And since Korean mothers in the postpartum period often eat the soup three times a day, the dose could rise as high as 5,000 micrograms, a whopping 17 times the recommended amount.

But some South Korean doctors are skeptical of the Australian health department’s judgment.

“Iodine is a double-edged sword. For some patients with certain thyroid conditions, high intake of iodine can be dangerous, but iodine itself is undoubtedly an integral element of human body,” said Choi Sei-hwan, the president of the Korean Medical Society for Intravenous Nutrition Therapy. Choi added that since not all iodine intake goes directly to the thyroid, the Australian health officials may be overreacting.

Seaweed soup as postpartum food is a long-standing tradition in South Korea. According to an early eighth century document from the Tang dynasty, Koreans served seaweed to women after childbirth, after seeing whales feeding on seaweed to treat postpartum wounds.

It’s probably too extreme to denounce miyeokguk altogether. But just to be safe, because we are in doubt, let’s exercise some moderation.

Cover image: Miyeokguk, or seaweed soup. (Source: Honeykki)