Evidence-Based Nutrient Recommendations

Iodine Content of the Breastmilk of Vegetarians and Vegans


by Jack Norris, RD, LD

We’ve updated our Iodine article with a new study on the iodine content of the breastmilk of vegetarians and vegans.

Pawlak et al. (2022, United States) compared the iodine content of breastmilk of 12 vegans, 6 vegetarians, and 12 omnivores; the median iodine content was 65 lg/L (32– 194 lg/L), 108 lg/L (62–189 lg/L), and 99 lg/L (62–1,719 lg/L) respectively. The difference between diet groups wasn’t statistically significant. Although 75% of the vegans used supplements, the researchers didn’t determine whether they contained iodine.

The researchers estimated a daily iodine intake of each infant, assuming a daily breastmilk intake of 0.78 L per day, and found that 75% of vegans, 67% of vegetarians, and 58% of omnivores wouldn’t meet the DRI; the difference between diet groups wasn’t statistically significant. We don’t know if any of the infants in this study were suffering from iodine deficiency. According to the researchers, the low iodine content of breastmilk could be more of a concern for vegan infants because vegan mothers are more likely to breastfeed and to breastfeed for longer periods than omnivores.

The authors write that “[The American Thyroid Association] and the American Academy of Pediatrics (AAP) recommend using 150 µg/day iodine supplements during lactation. Only ~15% of lactating women in the United States adhere to this recommendation.”

Pawlak R, Juddb N, Donati GL, Perrin MT. Prevalence and Predictors of Low Breast Milk Iodine Concentration in Women Following Vegan, Vegetarian, and Omnivore Diets. Breastfeed Med. 2022 Nov 24.

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