Iodine is required to ensure proper development and metabolism in humans. It influences brain development, helps prevent cancer, damage due to radiation and is used to prevent surgical infections.
Health Benefits of Iodine
1) Iodine Influences Brain and Nerve Development
Besides mostly statistical studies linking the lack of iodine in the diet to the health of young children, there are several studies that show its direct effects of on the brain in course of early development (R1, R2).
It was shown on the rats that iodine directly influences the migration of cells into the brain (R1).
The incoming cells help form a part of the brain that is responsible for problem – solving and analysis of information (R1).
The improper brain development was connected to the fact that newborn rats born to mothers with iodine deficiency performed worse in navigating mazes (R1).
Iodine is also important for the proper formation of nerves (R3).
In the case of rats that received excessive iodine, it was shown to disrupt the production of two proteins important for brain development – BDNF and NSP-A (R2).
Iodine excess on the mothers was also associated with problems in learning and orientation in their offspring (R2).
2) Sufficient Iodine Influences Cancer Development
Statistical studies have shown that iodine deficiencies do not cause thyroid cancers directly, but support their development and are connected to the development of more aggressive and less treatable thyroid cancer types (R4).
Iodine is being taken up by the cells in many organs and tissues, including breast, prostate, stomach nerves and pancreas (R7).
This theory was corroborated by statistical and immunological studies (R6).
It is supposed that iodine supports normal function and integrity of certain organs, including the breast (R10).
It was shown that addition of iodine and iodolactone to the cell cultures of different types of prostate cancer causes cell death and blocks their growth (R11).
It was also shown that molecular iodine (I2) blocked cancer growth in cell cultures of the breast, lung, prostate and pancreatic cancer (R12).
It was both blocking the generation of new cancer cells and inducing cell death (R12).
Iodine also prevents the damage of fats by oxygen, which can also serve as a protective measure against cancer development (R13).
Potassium iodide was also shown to protect DNA of the mitochondria in pig’s thyroid (R14).
A statistical study carried our in South Korea has shown that eating gim (a species of algae often used as food in the area) can lower the possibility of breast cancer development (R15).
In the case of fibrocystic breast disease, the addition of molecular iodine to the other medications has improved the patients` condition in 70% of the cases (R16).
It was also shown that addition of 0,1% of iodide or iodine to the treatment of rats with oncogen – induced breast cancer leads to cancer cell death (R17).
It was also shown that though medium doses of molecular iodine beneficial for cancer treatment can cause mild Wolff-Chaikoff effect they do not cause severe damage and can be added to the treatment trials (R18).
For any form of iodine to be effective in cancer therapy, the cells have to possess proteins that transport iodine into the cells (R19).
Most well-researched protein with such function is sodium/iodide symporter (NIS), a protein that helps the cell take up iodine inside (R19).
In the experiment carried out by a L. Zhang et al., it was shown that if the cells of non-small cell lung cancer are changed so they contain the active gene for NIS and then potassium iodine (KI) is added to the cell culture, the cells begin to take iodine in and die (R20).
Another way to force the cancer cells to take up iodine is to transfer modified cancer cells that produce NIS into the tumor (R21).
This method was shown to be effective in the mice with liver cancer (R21).
In this study, stem cells that are able to produce NIS under conditions without oxygen were introduced into the liver tumor in mice (R21).
After stem cells introduction, the rats were treated with radioactive iodine and the tumor began to take the element inside (R21).
The iodine helped to block tumor growth and increased the animals’ chances to survive (R21).
There is also data obtained from mice that combined introduction of engineered stem cells and radioiodine can help battle metastatic prostate cancer (R21).
Radioactive iodine is often used for treating patients after operations for several types of cancers, most notably thyroid cancer (R22).
Usually, an isotope called I131 is used (R22).
Implantation of radioiodine “seeds” into the tumor in the case of pancreatic cancer were also shown to both blocks the tumor growth and prevent the growth of the tumor around the nerve, which often makes tumors inoperable (R23).
Seeds containing radioactive iodine I125 added to the cultures of different stomach cancer lines also induced cell death and made them less viable (R24).
Also, radioactive iodine is used in another anti-cancer approach – it is connected to the proteins that inhibit telomerase (R26).
Telomerase is a protein that cancer cells used to repair their chromosomes and that is giving the cancer additional protection from radiotherapy and chemotherapy (R26).
It was shown on cancer cells line culture with an active telomerase gene that addition of protein that both blocks the activity of telomerase and contains radioiodine increases the rate of cancer cell death (R26).
It should be noted that radioiodine therapy can lead to complications and development of leukemia (R27).
3) Iodine Prophylaxis Is Helpful In Case Of Nuclear Catastrophe
It is well known that potassium iodine (KI) intake is recommended in case of disasters connected to the spread of radioactive materials, such as catastrophes on Chernobyl nuclear plant and Fukushima nuclear plant (R28, R29).
The main reason iodine has some efficacy is that regular iodine competes with radioactive iodine, so the cells take it instead of a dangerous variant (R28).
It was shown that addition of regular iodine to the culture of thyroid cells after irradiation not only improves their chanced of survival, it also prevents the destruction of genetic material inside the cells (R28).
It is proposed that besides eliminating its radioactive “competitor”, iodine eliminates dangerous types of molecules generated by irradiation that can potentially damage the DNA (R28).
Research suggests that the optimal dose of KI in the case of accidental radiation exposure is 15 mg daily (R29).
The current opinion that the risk of thyroid cancer development and other side effects after radioiodine accidental release is higher that risk of iodine toxicity from KI supplementation (R30).
Moreover, in the case of radiation exposure people with goiter and other disorders caused by iodine deficiency are even at more risk from radiation (R30).
So even there is an increased risk for newborns and elderly, KI supplementation after accidental radiation exposures is highly recommended and is included in WHO guidelines (R30).
It should be noted though that meta-analysis of the literature on the topic has not found enough evidence to strongly prove that KI intake after exposure may prevent thyroid cancer (R31).
4) Iodine Is Used To Prevent Surgical Infections
Iodine solution is widely used for disinfecting cuts and small wounds.
It is also often used in eye surgeries (R34).
There is some controversy concerning the efficacy of povidone-iodine, as bacteria develop resistance to antiseptics as well (R38).
There are some really unexpected properties of iodine and it is interesting to monitor the latest research on the subject.