Iodine deficiency is something of the past and the ‘goitre’ which is an enlarged thyrdoid no longer exists.   

We set out to eradicate this largely preventable health issue by adding iodine (potassium iodate) to table salt. Since this introduction, goitre have been largley eradicated and iodine deficiency has been unheard of in the western world.

Or so we thought.

What we are seeing today is a return of mild to moderate iodine deficiency. Why is this?

The advent of the low salt diet as a response to high levels of hypertension (high blood pressure) in the community during the 21st century meant that the general health guidelines included advice to reduce salt wherever possible. The reason for this is because an increased sodium concentration increases fluid retention which in turn increases pressure on the blood vessels, kidneys and cells, and increasing blood pressure in susceptible individuals. So the public health message to avoid salt, is not necessarily meant for the whole population. However if you ask any member of the public about salt, most would say that a low salt diet is a healthy one. And healthy individuals with a healthy diet usually eat lots of potassium containing foods such as vegetables and fruit and don’t need to avoid salt in the first place. So healthy individuals are at a higher risk of being iodine deficient! Those with a high salt diet, i.e. a highly processed diet, are more likely to be iodine replete, but overweight. However it is worth noting that the food industry does not have a mandate to use iodised salt so many high salt food products still may not have iodine included.

Secondly, seafoods are the highest source of iodine. Kelp and seaweed contain a very high level of iodine, so populations that eat a high level of seafood tend to have much higher iodine intake than populations that don’t live near the sea. This includes fish and shellfish. So people who don’t like seafood or live far from the ocean usually have a lower overall intake of iodine. 

Thirdly, the advent of himalayan salt (rock salt) and sea salt is the third risk factor for low iodine. Once again, healthy people tend to think they need less salt and one of the selling points of himalayan salt and sea salt is that it isn’t a pure chemical form of salt (sodium chloride) and naturally contains other minerals. Consumers are under the impression that rock salt & sea salt contain enough iodine for their needs.  But it doesn’t.  In truth the mineral content does not contain enough iodine to cover the basic needs of the human body, and since we have become reliant on salt as a form of iodine (and thus not ensuring we eat seaweeds or seafoods several times per week) people who use only rock salt are at significant risk of becoming iodine deficient over time. 

Iodine is an important and vital nutrient for thyroid hormone production, breast health, brain health & development and overall metabolism. A goitre may be small and not easily noticable and many doctors are unaware of iodine deficiency in the population (due to its disappearance) therefore not looking for it. Symptoms of low iodine mimic hypothyroid symptoms so another clue is the presence of hypothyroid symptoms but clinically normal thyroid blood tests. 

The recommended daily intake for iodine is at least 150 micrograms. If you want to continue using rock or sea salt just add 1/3 kelp flakes to it.

If you want to test your iodine levels you can request a spot test as your doctor which shows the amount of iodine in the urine or for a more accurate picture we can do a 24 hour iodine loading test which shows how much iodine you absorb in a 24 hour period. See here for more details. 


Simone Reddington is the founder of the Apothecary, a Medical Herbalist and thinker. She holds a degree in Psychology and is a professional member of the New Zealand Association of Medical Herbalists.