Excessive iodine is a condition where the body has too much iodine in it. Iodine is an important part of thyroid hormone. Since the human body does not make iodine, a person must get enough in their diet. While many people can take in a little more iodine than is needed without difficulty, for some people, too much iodine can lead to thyroid problems. Very large amounts of iodine can lead to iodine toxicity.
Iodine is found in supplements, iodised table salt, some drinking water, milk, seaweed, and certain types of seafood. Some medications also contain iodine.
The recommended amount of iodine per day is:
The symptoms of excess iodine vary between person to person. Underlying factors, such as how a person’s thyroid was functioning before consuming too much iodine, play a role in what, if any, symptoms the person gets.
A patient with excess iodine which leads to low thyroid hormone levels (hypothyroidism) can have symptoms such as:
A person with excess iodine which leads to high thyroid hormone levels (hyperthyroidism) can have symptoms such as:
For people with mild iodine toxicity, the first symptoms are usually digestive. The person may have nausea, vomiting, diarrhoea, or abdominal pain. For people with more severe iodine toxicity, the person may have severe mental changes (such as seeing things which are not there, suddenly irrational thoughts, becoming difficult to wake), coma or shock.
Excessive iodine is caused by having too much iodine in the body, either from dietary sources or taking too much in supplement form.
Some people are more likely to develop symptoms from excessive iodine. Those who are more at risk include:
Excessive iodine and iodine toxicity are not common. However, the symptoms of excessive iodine are similar to many other different illnesses. As a result, a person with excess iodine, depending on their symptoms, is likely to require:
Ultrasound scan of the neck if the thyroid feels enlarged or there is a goitre
Excessive iodine and iodine toxicity are not usually fatal. Possible complications can include:
Possible thyroid cancer. The research is unclear as to whether excess iodine can lead to thyroid
There is no specific treatment for excess iodine, other than to get the levels back to normal. If a person has iodine toxicity, they may be given activated charcoal in A&E to cleanse the digestive system. They will then stay in hospital for monitoring to make sure that they remain stable.
If thyroid problems occur because of excess iodine, treatment will depend upon the type of thyroid problem.
The best prevention for iodine excess is to not take in too much iodine. This is easier when a person knows they are taking in too much iodine. However, this can be more difficult, for example, if a water source has too much iodine in it, but the local community is unaware. It is important for a person to read the labels of any vitamin or supplement to confirm they are taking it correctly.