Iodine is an interesting element because we only need 5 grams in our entire life to meet the physiological requirements of this Halogen . "A small dose goes a long way" is the perfect way to describe iodine because it is essential for the proper functioning of the thyroid gland and deficiencies in iodine will almost always lead to an underactive thyroid . It is estimated that over 2 billion people worldwide have an iodine deficiency and even 50 percent of Europeans are believed to have some form of mild iodine deficit . You don't even need to have a fancy medical degree to be able to find a treatment for this solution logically: if a patient doesn't have enough iodine, all he has to do is take some extra supplements to be healthy again! If this is the treatment plan you came up with, I suggest keeping your day job because you may find yourself in some malpractice trouble if this is what you tell your patients. Here is what you need to know about iodine.
Iodine — the Nutrient
I see what you are thinking; iodine cannot be all bad because a lot of our foods are fortified with iodine to help stave off iodine deficiencies; surely the government wouldn't be poisoning us. From 1924, foods have been fortified with iodine in the United States because millions of Americans had been suffering from the iodine deficiency disorder. Iodine deficiency virtually disappeared, but cost-saving measures gradually won out as food no longer received the same preparation.
Unfortunately, it turns out these cost-saving measures have not benefited society. In the early 1970's, less than 1 percent of pregnant women had an iodine deficiency, but in 2000, that number was over 7 percent.
Women require 50 percent more iodine during pregnancy due to their increased metabolic demand . Fetuses that do not have adequate iodine supplementation will become mentally retarded because iodine is crucial in neurodevelopment at this stage of life .
As you can see, iodine is essential and can be taken in small quantities to alleviate deficiencies. The World Health Organization (WHO) has called for countries to make attempts to change legislation to ensure all salt is once again fortified with iodine as well as adding iodine to prenatal vitamins to make sure that fetuses develop properly. . While we wait for the bureaucratic wheel to spin, it is wise to consult with your physician, especially if you and your partner are trying to become pregnant to make sure you are informed about the benefits of iodine.
Iodine - the Toxin
When managing your underactive thyroid, this can become quite dangerous because too much iodine has the potential to cause hyperthyroidism, increase your chances of developing thyroid cancer and even speed up osteoporosis . In a recent article, I discussed how supplements for hypothyroidism are often dangerous because an "over-the-counter" product does not have to meet the same safety requirements that a drug requiring a prescription for must meet .
To prove my point further, scientists conducted a recent study on 10 of the most popular supplements for hypothyroidism on the market and they wished to determine how much active thyroid hormone was present in these medications. They found that nine of the ten supplements had active levels of thyroid hormone already and that five of the ten had levels of a hormone that exceeded the daily recommendations for thyroid medication. 
Numerous population studies have been conducted to determine the threshold for proper levels of iodine in the population before the risks outweigh the benefits. In a study containing over 3,000 participants, groups were established based on iodine supplementation, and the prevalence of hypothyroidism was assessed at the end of a 5-year period. Researchers determined that as the levels of iodine from diets increased, the cases of overt hypothyroidism or subclinical hypothyroidism increased .
In animal studies, it scientists determined that chronically elevated doses of iodine are also potentially teratogenic. Researchers found that rats fed high levels of iodine tended to have more visible signs of hypothyroidism such as enlarged thyroid glands (goiter), decreased appetites and lower birth weights. Scientists also observed that the higher the dose of iodine, the less likely the fetuses survived after birth.  Animal studies are often a preferred substitute to human studies in the event human subjects are put in unnecessary danger so it is logical to assume that a similar relationship would happen in human subjects.