Cow’s milk as an important source of iodine for prenatal health and how switching to plant-based milk can lead to iodine insufficiencies
Iodine insufficiencies are common among many populations, particularly in pregnant women. One of the main functions of iodine is making thyroid hormone. The two main hormones which iodine influences are triiodothyronine (T3) and thyroxine (T4). Thyroid hormone is essential for the metabolism of the majority of tissues in the body. For the average adult, the Recommended Dietary Allowance, RDA, for iodine is 150 µg. During certain stages of life, such as pregnancy and infancy, the importance of iodine is even greater as it supports brain and bone development. The RDA for iodine during pregnancy is 220-250 µg and while breastfeeding, the RDA is 250-290 µg. Consuming enough iodine in the diet during pregnancy helps support fetal neurodevelopment. Iodine is found in several food sources such as seafood and iodized salt, however dairy products are one of the major sources of iodine in American diets. It is important to note that only bovine milk products are rich in this mineral. As the usage of iodized salt decreases, dairy has become an even more important source of iodine. In recent years, diets have begun to shift towards being more plant-based. Specifically, consumers have been using plant-based milks such as almond, soy, and oat milk rather than cow’s milk. Plant-based milks do not naturally contain iodine and are not fortified with iodine as it can alter the flavor profile of the product. It has been shown that women of childbearing age who have switched to plant-based milks as opposed to cow’s milk have lower iodine levels than women who consume cow’s milk. This is of concern for all stages of life, but particularly pregnancy and infancy. This review will focus on the importance of iodine in the diet to support prenatal health, lactation, and infant health.