Salt & Iodine
What is iodine?
Iodine is an essential mineral. It is an integral part of the thyroid hormone that controls human growth and development. Historically, New Zealand soils were known to be low in iodine, and this resulted in a high rate of goitre (a condition where the thyroid gland becomes enlarged due to an inadequate intake of iodine) amongst New Zealanders early this century.
One of the nutrition messages nutritionists have repeated for years is eat less salt. However, in New Zealand, our table salt has had iodine added. Does some recently released research on our iodine status mean we should go back to those heavy handed days with the salt shaker?
The History
In the 1920's it was decided to add iodine to our table salt supply and this resulted in a decreased rate of goitre amongst the New Zealand population.
In more recent times, up until the mid 1980's, we have also had a significant source of iodine from dairy products. Iodine containing compounds were used in the processing of milk products and small amounts were passed on to us in the milk products available. These iodine containing compounds are no longer used and so milk is no longer such a significant source of iodine for us, although it still provides some iodine.
Because of the low soil levels, we have always monitored New Zealander’s iodine status. Recently, there have been a number of studies that have shown a re-emergence in iodine deficiency in New Zealand.
What is being done to fix the problem?
Since September 2009, manufacturers have replaced non-iodised salt with iodised salt in bread. The salt iodisation level is in the range of 25-65 mg of iodine per kg of salt. This range is the same as the current iodised (table) salt range. Organic bread is exempt from this mandatory fortification.
Should we eat more salt?
No, we get more than enough salt (which is not iodised) from processed foods, however, we should make certain that if salt is added in cooking or at the table it is iodised.
What other foods contain iodine?
Seaweed is a good source of iodine so sushi is a great option. Other foods include seafood (fish and shellfish) seameal custard, milk and eggs.
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