• Question: is iodine dangerous

    Asked by jackh13 to Dilwar, Lou, Rachel, Simon, Susan on 11 Nov 2013.
    • Photo: Simon Langley-Evans

      Simon Langley-Evans answered on 11 Nov 2013:

      Everything is dangerous in the wrong amount. Iodine is one of the elements that the human body needs. Without it the function of a gland called the thyroid goes wrong and this can make us suffer from a number of diseases. In adults the next swells up to form a big lump called a goitre. In children lack of iodine can cause brain damage. The amount we need to avoid these problems is tiny- just 90 millionths of a gramme! Too much iodine can cause lots of problems with our digestive system- vomiting, diarrhoea, pain and can also cause a high fever and hallucinations. To get a toxic effect you would need to consume it from something other than food, like a disinfectant. Consuming more than a couple of grammes would kill an adult.

    • Photo: Susan Skelton

      Susan Skelton answered on 12 Nov 2013:

      This is a good question and the answer depends on the type of iodine.

      As Simon says, some iodine is required for the body to function normally. Nearly all of the iodine in your body is absorbed by the thyroid gland.

      There is a certain type of iodine called radioactive iodine which is produced by nuclear reactions and can be released into the environment when there is a nuclear explosion, such as the nuclear disaster in 2011 in Japan. Radioactive iodine is very dangerous.

      The thyroid gland cannot tell the difference between radioactive iodine and non-radioactive (stable) iodine, so it absorbs both types. The radiation from the radioactive iodine can destroy the thyroid gland. People living near nuclear disasters must take pills of stable iodine so that the gland is “full” of stable iodine and doesn’t absorb any of the nasty radioactive iodine.

      Although it is harmful, radioactive iodine can also be used to treat cancer in the thyroid gland, because when it is absorbed it kills any thyroid cells that take up iodine, including cancer cells.

    • Photo: Rachel Dakin

      Rachel Dakin answered on 14 Nov 2013:

      Before doing I’m a scientist the only thing I new about iodine was that weak solutions are used as disinfectants. You used see this in hospitals (or tv programmes about hospitals!) when they rub a brown liquid over an area of skin before starting surgery. This is a very diluted solution and therefore different to the pure stuff.
      I love that iodine as purple when it is a gas – such a pretty element!

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