A recent study discovered unusually high levels of a specific thyroid hormone, as well as thyroid peroxidase and thyroglobulin antibodies, in breast cancer patients, implying a connection between thyroid disorders and breast cancer.(1)
While nearly 14% of American women are currently living with breast cancer, anywhere between 10 and 40% of the adult population of the United States lives with some form of thyroid disorder.
A link between the two, such as a common cause, could explain why the United States population has seen an uptick in recent years of glad-related illnesses – including various types of cancer. Now, some researchers and doctors believe that that link may be iodine deficiency.
Explaining The Link
In order to understand how iodine deficiency may be contributing to both certain cancers and thyroid disorders, it’s important to understand how iodine functions in the body.
“Iodine enters the body in the form of iodate or iodide in the water we drink or food we eat,” one paper explains(2); “The iodate is converted into iodide in the stomach. The thyroid gland traps and concentrates iodide and uses it in the synthesis and storage of thyroid hormones… it is estimated that 75% of the iodide taken into the body each day enters the thyroid by active transport. About two-thirds of that is used in hormone synthesis, with the remaining amount released back into the extra cellular fluid. The thyroid gland contains the body’s largest pool of iodide, about 8 to 10 mg. Most of this iodide is associated with thyroglobulin, a thyroid hormone precursor and a source of hormone and iodinated tyrosines.”
In other words, iodine plays an essential role in hormone production, and is particularly useful to the thyroid.
A paper in the journal Thyroid: The Journal Of The American Thyroid Association outlines the connection between prolonged iodine deficiency and the development of specific types of cancer, particularly thyroid tumors, in animal models(3).
The link between iodine deficiency and thyroid disorders is further explored in an earlier study, published in the same journal, which outlines the role that iodine deficiency can play in exacerbating thyroid conditions(4).
Iodine Deficiency: A Global Problem
We get about 90% of our daily iodine intake from the food we eat, and the remainder from the water that we drink – seaweed is particularly rich in iodine, as are spongy shells, sea fish, and leafy greens like spinach.
But despite there being many available dietary sources of iodine, experts estimate that at least 1 billion people worldwide are at risk for iodine deficiency(5), and the consequences can be severe: endemic goiter, cognitive disabilities, a decreased fertility rate and increased risk of miscarriage, and infant mortality are all risks of severe iodine deficiency.
Pregnant mothers and young infants need to be especially careful when it comes to preventing iodine deficiency – the consequences are potentially most serious for fetuses and young children.
A recent article from the journal Pathology outlines a promising solution: more comprehensive screening for iodine deficiency, combined with public health programs targeting parents and young children.
“The availability of sophisticated, sensitive and accurate laboratory testing procedures provides an efficient and effective platform for the application of screening for these disorders,” the author writes.
Iodine deficiency is easy to screen for: “Measurement of urine iodine concentration (UIC) in school children or pregnant women is the recommended indicator for screening populations for iodine deficiency.”(6)