Iodine loss in rice cooker using iodized salt
For people on a plant-based diet not taking supplements, iodine is needed through iodized salt. A simple way to meet that need is by using iodized salt in cooking. In the US , one heaping teaspoon of iodized salt provides the recommended amount of iodine (since ~50% of iodine is lost while boiling, 150 mcg  for most adults).
Iodine retention while boiling rice = 68% = ~50% for simple math.
Do you think the iodine loss when using a rice cooker roughly equates to boiling?
 Dasgupta PK, Liu Y, Dyke JV. Iodine nutrition: iodine content of iodized salt in the United States. Environ Sci Technol. 2008;42:1315-23.
 Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2001.