Iodine – why its important not to overlook this mineral in our diet
Although iodine tends not to be the first nutrient that springs to mind as a concern, this mineral is an essential part of all our diets as it is not produced by the body. Iodine deficiency has been described by the World Health Organization as the ‘the world’s greatest single cause of preventable brain damage’. Its needed to make our thyroid hormones, and these hormones are essential for many body processes including growth, regulating our metabolism and for the development of a baby’s brain during pregnancy and early life healthy growth and development.
Most people in the U.K. reach their iodine requirements, but at-risk groups for iodine deficiency are: those who avoid dairy (this is our main source of iodine in the U.K.), pregnant & breastfeeding women (due to the increased requirements).
Fish and shellfish, milk and other dairy foods (e.g. yogurt) provide the most amount of iodine per average portion. White fish provides more iodine than oily fish. Non-animal products such as cereals, potatoes, nuts and fruit and vegetables also contain some iodine but at much lower concentrations than animal sources of iodine, and even if eaten in large quantities are alone unlikely to provide enough iodine to meet requirements. For most adults in the UK, on average, over a third of their iodine comes from milk and other dairy foods. About 300 ml of milk is enough to meet the UK recommendation of 140 µg of iodine per day for an adult. Plant-based milk alternatives contain negligible amounts of iodine, although a few iodine-fortified products are now available (check the label). Seaweed is another good source but isn’t recommended more than once per week, especially brown seaweed like kelp, as excessive iodine can also cause thyroid problems.
So be aware if your diet is low or contains no dairy, shellfish or white fish particularly if you are planning a pregnancy or breast-feeding. If you have just switched to plant milks, then find one that does fortify with iodine and if you are vegan consult your GP to find the right iodine supplement for you.