Minerals and trace elements - Iodine
Iodine is an essential component of the thyroid hormones, thyroxine and triidothyronine, which are vital regulators of metabolic rate and of physical and mental development.
Iodine deficiency results in lethargy and swelling of the thyroid gland in the neck which forms a goitre. Iodine deficiency is relatively rare in the UK but is still prevalent in many areas of the world, where it remains a major nutritional public health issue.
Infants born of severely iodine deficient mothers may be mentally retarded (cretinism).
With regard to low dietary intakes in the UK, data from the NDNS indicate that 12% (1 in 8) young women have intakes below the LRNI. This may be associated with low intakes of milk and milk products.
Excess iodine is not absorbed so toxicity is unlikely in healthy individuals.
The amount of iodine in plant foods such as vegetables and cereal grains is determined by the amount of iodine in the growing plant’s environment, and the amount in the soil or water can vary dramatically. The only rich sources of iodine are seafoods (sea fish, shellfish and seaweed), but milk is also a source. In some countries certain foods, e.g. salt and bread, are fortified with iodine.
© British Nutrition Foundation