Does iodine protect against radioactivity

- and what else does it do?

The Russian invasion of Ukraine has increased the fear of nuclear warfare or radioactive leaks from local nuclear power plants. For that reason, many people have purchased iodine tablets to protect themselves from radioactive contamination. Being relatively close to a radioactive leak creates a sudden need for very large intake of iodine. It is important to realize, however, that the thyroid gland can only store iodine for a limited period of time and it can be dangerous to take extreme doses of iodine. Therefore, it makes no sense to take mega-doses as a preventive measure. On the other hand, it looks as if iodine deficiencies are rather common. Furthermore, we do need a certain amount of iodine to support the thyroid function, estrogen balance, and a number of other things. The question is how much iodine do we need on a day-to-day basis and how much do we need in the case of being exposed to radioactive radiation?

In the case of radioactive exposure from nuclear warfare or from nuclear power plant radiation leaks, radioactive iodine is one of the first things to be released into the atmosphere. You cannot see, smell or taste it. You breathe it or get it through your skin.
Radioactive iodine (I-131) increases the risk of thyroid cancer because it gets stored in the thyroid gland. In the case of a radiation leak, radioactive iodine is spread to the surroundings together with other radioactive compounds such as cesium (cesium-137) and strontium (strontium-90). Radioactivity is also associated with acute leukemia, eye diseases, and mental disturbances. Over the course of time, other cancer forms may develop, and there is a risk of genetic damage that may cause deformities. This was seen after the nuclear bombing of Hiroshima and Nagasaki in Japan during World War 2 and after the nuclear disaster at Chernobyl in 1986. In worst case, brief exposure to high doses of radioactivity can result in death after a few hours or days.
Of course, it makes a difference how far you are from a potentially threatening radioactive leak. The half-life of radioactive iodine is eight days. International guidelines only suggest high-dosed iodine supplementation for individuals within a 100-200-kilometer radius of a nuclear spill. Here, the wind direction also matters. Radioactive iodine is potentially life-threatening, whereas regular iodine in the right doses serves as an antidote.

Why iodine is an essential mineral

Iodine is an essential mineral that we need from our diet or from supplements in a stable form (sodium iodide). After iodine has been ingested, it is stored in the thyroid gland where it helps form thyroid hormones. Iodine is also important for brain development, the ovaries, the estrogen balance, and a number of other functions.
Lack of iodine can cause goiter and hypothyroidism, a very common disorder. Hypothyroidism is insidious and linked to symptoms such as extreme fatigue, difficulty with concentration, cold intolerance, weight gain, swollen neck, a tendency to feel depressed, and various other symptoms. An iodine deficiency can also increase the risk of breast cancer, and iodine deficiency during pregnancy can increase the risk of giving birth to a retarded child.

Iodine sources and widespread deficiency problems

Fish and fish sauce, shellfish, and eggs are all good sources of iodine. Also, different types of seaweed such as kombu, agar, arame, wakame, oarweed, and sugar kelp contain a lot of iodine compared with other seaweed species. Occasional consumption of high doses of dietary iodine does not pose a health risk. The body excretes what it doesn’t need. On the other hand, there is not enough iodine in table salt and Himalayan salt to cover the daily need.
Around two billion people worldwide are believed to lack iodine, primarily as a result of dietary shortcomings and iodine-depleted farmland, a problem that can affect the entire food chain.
Many countries have introduced mandatory iodine enrichment of normal table salt to prevent goiter. This has definitely improved public health but many people remain iodine-deficient.
What is more, it appears that various fluoride compounds in the environment can interact with and block out iodine, thereby increasing the need for this mineral.
The reference intake (RI) level for iodine in Denmark is 150 micrograms per day for adults. Many experts and scientist believe we need even more. The European Food Safety Authority (EFSA) has set 600 micrograms per day as the safe upper intake level for adults.

Iodine supplements

You can buy supplements that contain sodium iodide that is a stable form of iodine. Also, there is Lugol’s iodine (named after the French doctor, J. GA. Lugol), which is a solution that contains 5% iodine and 10% sodium iodide mixed with 85% distilled water. Most studies of iodine have been conducted with Lugol’s iodine which appears to be a safer source for high-dosed consumption.
In cases that call for high-dosed supplementation, it is recommended to consult with a physician or relevant health professional to avoid overdosing.

What happens if you get too much iodine?

The thyroid gland can only store a limited quantity of iodine. If you get too much iodine – especially from supplements – it may result in an overactive thyroid gland, hyperthyroidism, elevated blood pressure, abnormal heart rhythm, and strained kidneys. It also appears that excessive amounts of iodine can block the production of thyroid hormones and cause the same symptoms as those seen in connection with an iodine deficiency. It should also be mentioned that patients suffering from the autoimmune thyroid disorder called Hashimoto’s thyroiditis that causes the metabolism to slow down should limit their iodine intake. Also, it is important to balance your intake of iodine and selenium, another micronutrient that is important for the metabolism.

Guidelines in the case of acute exposure to radiation

In the case of acute exposure to large quantities of radioactive radiation the international health authorities recommend ingesting potassium iodide in the following doses, which are way above the reference intake (RI) level of 150 micrograms.

Adults: 130 milligrams
Children and youngsters aged 3-18 years weighing less than 68 kilos: 65 milligrams
Children from one month to 3 years: 32 milligrams
Neonates up to one month of age: 16 milligrams

Iodine tablets that are used in the case of radioactive radiation typically contain very high concentrations (65 mg) of potassium iodide and are prescription only. There are varying policies for handing out high-dosed iodine tablets, as it depends on whether or not the countries in question have nuclear power plants. The ongoing war in Ukraine has also added focus to the problem
As mentioned earlier, only take these very high iodine doses if you are within a 100-200-kilometer radius of a radioactive leak. You get the optimal benefit by taking the iodine supplements within 24 hours prior to being exposed to radiation or as soon as possible immediately after exposure. If you wait longer than 24 hours after being exposed, these high doses of so-called stable iodine have no effect and should not be taken.
In some situations a single treatment is recommended. According to the Danish Health Authority, iodine therapy should normally be discontinued after one week. Pregnant and breastfeeding women should at the maximum take high doses of iodine twice.
If a radioactive leak occurs, it is advised to follow the Danish Health Authority’s most recent guidelines, especially because the situation depends on factors like the amount of radioactivity and the duration of the leak.
If you are unable to get a hold of stable iodine for acute situations, you can choose to take one of the types of seaweed that has a high iodine content - but be careful not to get too much.

How does iodine protect against radioactivity?

If you ingest stable iodine (potassium iodide) at the right time, it can reduce (by up to 99%) the thyroid gland’s uptake of radioactive iodine. Once the thyroid gland is saturated with stable iodine the body’s iodine stores are filled and any radioactive iodine that enters the body will be excreted in the urine. That way, stable iodine lowers the risk of developing thyroid cancer as a result of being exposed to radioactive iodine (but it does not protect other parts of the body against cancer). This strategy only protects the thyroid gland for up to three days, and it is not advisable to take high doses of stable iodine for extended lengths of time as it may cause side effects.
Also, potassium iodide only protects against radioactive iodine but not against other radioactive compounds like cesium and strontium. Radioactive compounds can attack our skin but the damage can be limited by using soap and water.

References

Joseph Mercola. Why People Are Rushing for Iodine Amid Nuclear Concerns. March 31, 2022

Why People Are Rushing for Iodine Amid Nuclear Concerns (mercola.com)

Radiation: Does iodine help? | Science | In-depth reporting on science and technology | DW | 04.03.2022

Jennifer Draper et al. Iodine. Medicine Libre Texts. Nov. 2020

Kristian Sjøgren. Derfor skal der være jod i dit husholdningssalt. Videnskab.dk 31. oktober 2018

Rychlik W. The need for iodine supplementation. OMS 12. 06. 2017

Frederick R. Stoddard et al. Iodine Alters Gene expression in the MCF7 Breast Cancer Cell Line: Evidence for an Anti-Estrogen Effect of Iodine. International Journal of Medical Sciences. 2008

Qian Wu et al. Low Population Selenium Status is Associated With Increased Prevalence of Thyroid Disease. The Journal of Clinical Endocrinology & Metabolism 2015.

Weiping Teng et al. Effect of Iodine Intake on Thyroid Diseases in China. New England Journal of medicine 2006

New York State. Department of Health. Potassium Iodide (KI) and Radiation Emergencies: Fact Sheet.

Potassium Iodide (KI) and Radiation Emergencies: Fact Sheet (ny.gov)

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