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Iodine to be taken in case of nuclear accidents

The risk of nuclear accidents increases day by day and the European Commission, instead of engaging in dialogue, is thinking of saving citizens by stocking up on iodine.
Nearly 3 million potassium iodide tablets have already been delivered to Ukraine, for 'protect people from the harmful effects of radiation'. (1)

We march for peace and we sign the petition for the Italian government to immediately stop participating in the conflict by sending weapons. However, we also prepare to protect our loved ones, knowing what to prepare and how to behave in the event of a nuclear alarm (2) but also how much iodine to take.

1) Nuclear accidents and iodine intake

1.1) Radiation and thyroid

WHO updated the guidelines on iodine to be taken in case of nuclear accidents in 2017. (3) During a nuclear accident, radioactive iodine can be released in a plume - such as volcanic plumes, which can reach 80 km in height (ESA) - and contaminate the environment up to hundreds and / or thousands of km away. (CD fallout).

Inhalation of contaminated air and ingesting contaminated food and drinking water can expose internal organs to radiation and absorption of radioactive iodine, primarily through the thyroid. The thyroid gland in fact uses iodine to produce thyroid hormones and does not distinguish radioactive iodine from the stable one.

1.2) Function of iodine

Stable iodine supply, within 24 hours before or at the beginning of exposure to radioactive iodine, saturates the thyroid and blocks the absorption of radioactive iodine. Thus effectively reducing internal thyroid exposure.

The administration oral stable iodine, along with the control of food and drinking water, is considered an appropriate strategy to reduce the risk of adverse health outcomes in people exposed to radioactive iodine.

2) The iodine to be taken in the event of a nuclear accident

Ready availability of iodine is essential in the emergency. Even therefore, tablets are the most recommended format. In any case, it is necessary to avoid taking high doses of iodine outside of emergencies.

2.1) When

Iodine it should only be taken in the emergency phase. Less than 24 hours before and preferably within 2 hours, at the latest 8, after exposure to radiation. Priority must be given to preventing exposure to radioactive iodine. (2)

It must be avoided to take iodine, vice versa, after 24 hours after exposure to radiation. Since in this case the damage is greater than the benefits, as the biological half-life of the radioactive iodine accumulated in the thyroid is prolonged.

2.2) How many times

One administration of stable iodine is usually sufficient. In the event that exposure to radioactive iodine is prolonged beyond 24 hours (or is in any case significant, as in the case of continuously exposed emergency workers),

- young adults only - excluding children, pregnant and lactating women, over XNUMX - should take a second dose of stable iodine.

Children and young people adults must be privileged if doses are limited.

2.3) Forms and formats

Potassium iodide (KI) is the most widely used form of iodine. Other forms - such as potassium iodate (KIO3) - are valid alternatives, with attention to taking the recommended quantities of iodine (see next paragraph). In tablets, powder or liquid solution.

The tablet format it is preferable, if the individual does not have swallowing problems, as it distributes better and causes fewer gastrointestinal irritation problems. In addition to being able to keep for a long time. (3) The tablets can also be crushed and mixed with some foods (eg fruit juices, jam, milk).

2.4) Doses

The doses of iodine to be taken vary in relation to age and format, as indicated in the following table.

iodine tab

2.5) Side effects

The side effects they are rare and include iodine-induced hyper- or hypothyroidism and allergic reactions. More serious reactions are sialadenitis (inflammation of the salivary gland), gastrointestinal pains and skin rashes.

Rarely Relevant complications such as herpetiform dermatitis or hypocomplementemic urticarial vasculitis have been observed, especially in subjects with prior thyroid disorders.

In cases of hypersensitivity to the thyroid gland, the simultaneous intake of potassium perchlorate is a solution to suppress theuptake of iodine. Iodine products with dyes should be avoided to reduce the risk of any allergic reactions.


Dario Dongo and Andrea Adelmo Della Penna


(1) European Commission. EU develops strategic reserves for chemical, biological and radio-nuclear emergencies. Press release. 6.4.22,

(2) Dario Dongo. Nuclear explosions, preparation and vademecum. GIFT (Great Italian Food Trade). 26.3.22,

(3) FAO (2017). Iodine thyroid blocking: Guidelines for use in planning and responding to radiological and nuclear emergencies. ISBN: 978 92 4 155018 5,

(4) Iodine tablets (e.g. potassium iodide, potassium iodate) - if stored in airtight packages, in a cool and dry place (not exposed to light, heat and humidity) - have a shelf-life about 5 years.

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Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.

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Graduated in Food Technologies and Biotechnologies, qualified food technologist, he follows the research and development area. With particular regard to European research projects (in Horizon 2020, PRIMA) where the FARE division of WIISE Srl, a benefit company, participates.

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