Iodine: biological information

Biological role of iodine: in nature, iodine exists as iodide ions, I-, and it is as iodide that it is taken into our bodies. Iodine is an essential component of the human diet and in fact appears to be the heaviest required element in the diet. Iodine compounds are useful in medicine.

Lack of iodine in the diet is a cause of goitre (Derbyshire neck). This condition is rare now as table salt is dosed with a little iodide.

Levels in humans

Table: the abundances of the elements in humans.
Human abundance by weight 200 ppb by weight
Human abundance by atoms 10 atoms relative to C = 1000000

How much iodine is in your body? Find out here.

You can use this form to calculate how much iodine your body contains. Enter your weight in either kilograms or pounds and click the "Calculate" button. You must enter a number, not text! Elements for which there are no data will always give a value of zero for the weight, no matter what you put in the weight box.

Calculate how much iodine is in your body
Enter your weight here: You contain about : grams of iodine

Hazards and Risks

Hazards and risks associated with iodine: elemental iodine, I2, is toxic, and its vapour irritates the eyes and lungs. The maximum allowable concentration in air when working with iodine is just 1 mg m-3. All iodides are toxic if taken in excess.

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iodine atomic number