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.
The main sources of iodine for people living in the United States tend to be seafood and dairy products. Milk and other dairy products are not naturally high in iodine. Cows are given iodine in their diets and Iodine-containing disinfectants are used to clean milking machines—the iodine from these products ends up in the cow’s milk.
Are plant milks comparable to cow’s milk in terms of iodine content? Apparently not.
Researchers examined 30 different plant milks from 16 different companies in the U.S. based on soy, almonds, rice, coconuts, pistachios, walnuts, hemp, and cashews (1). The milks averaged 3.1 µg of iodine in an 8-ounce glass. In comparison, cow’s milk had more than 30 times more iodine (96.8 µg in 8-ounces).
You can read about a similar study from the UK in Plant Milks and Iodine: Recommendations for Vegans.
Some have proposed adding iodine to plant milks—there are a few products with added iodine but this is not yet a common practice.
See our section on Daily Needs for information on getting adequate iodine on a vegan diet.