http://www.lifeextension.com/magazine/2011/10/The-Silent-Epidemic-of-Iodine-Deficiency/Page-01
The Silent Epidemic of Iodine Deficiency
In 2008, researchers concerned about the growing threat of iodine deficiency analyzed 88 samples1 of iodized table salt—the main supply of this critical micronutrient for most people.2
Less than half of those tested contained amounts of iodine sufficient for optimal health.
Coupled with the trend of reduced salt consumption, rates of iodine deficiency are now reaching epidemic levels.
In the developed world, iodine deficiency has increased more than fourfold over the past 40 years. Nearly 74% of normal, “healthy” adults may no longer consume enough iodine.3,4
In this article, the latest data on this dangerous trend are presented. You will learn of iodine deficiency’s profound impact on overall health. You will discover iodine’s vital role in thyroid function and its link to obesity, cognitive impairment, heart disease, psychiatric disorders, and various forms of cancer. You will also find out how iodine can help ward off breast cancer and fibrocystic breast disease.
In nature, iodine is a relatively rare element. It’s found in abundance in the ocean. Its presence in soil, on the other hand, is very low in many places around the world, including the United States.
Iodine is essential to life and especially crucial for brain development in children, making its deficiency the number one cause of preventable mental retardation worldwide.
It also plays a central role in healthy function of your thyroid gland. This is why the most visible symptom of iodine deficiency is goiter—the unsightly, painful enlargement of the thyroid gland that manifests as an enormous swelling around the neck and larynx.
While goiter was relatively common a few generations ago, most middle age and younger Americans have never seen it. This is largely due to the industry practice of salt iodization in this country, first implemented in the 1920s after the effects of iodine deficiency were recognized and since emulated around the world.2,5,6 (The Morton company was the first to add iodine to salt in 1924, after a successful public health campaign.)7 Unfortunately, as evidenced by recent FDA findings, many table salt makers are now failing to add iodine in quantities sufficient to support optimal health.
Other consequences of iodine deficiency, so-called iodine deficiency disorders (IDD), are subtle and may inflict greater damage.6,8 It is estimated that IDDs affect between 800 million and 2 billion people worldwide; reduction in salt intake is likely to drive those numbers still higher.2,9-11
The health benefits of reducing salt intake have been well established.9,12,13 Millions of Americans are slashing their use of salt to protect themselves against high blood pressure and cardiovascular disease.
But by cutting our salt intake we are also cutting our iodine intake, which is why mean urinary iodine levels (a measure of iodine sufficiency) plummeted by more than half over a 20-year period.4,14 Additional, otherwise healthy behaviors have also contributed to inadequate iodine intake. (See Table 1.)
The danger of low dietary iodine is further compounded by your body’s decreased ability to utilize it, the result of contamination by a ubiquitous environmental toxin called perchlorate.
Originally developed for explosives and rocket fuel,18 perchlorate now pervades ground water and food supplies throughout the US. It’s even used as a flavor-enhancer in certain foods.19-21 Perchlorate blocks the thyroid gland’s ability to absorb and utilize dietary iodine, an effect that is of concern when iodine intake drops off.18,22
The US recommended dietary allowance (RDA) for iodine is 150-290 micrograms (mcg) for adults, while the Food and Nutrition Board of the Institute of Medicine has set the tolerable upper limit at 1,100 mcg.18,23,24
These guidelines may be inadequate to address certain health conditions.
They were first established as sufficient only to prevent goiter. Daily doses for optimal health of 3,000-6,000 mcg have been used without side effects in studies of people with other iodine deficiency-related health conditions such as polycystic breast disease.18
By way of comparison, the average daily Japanese consumption of iodine ranges from 5,280 to 13,800 mcg of iodine, with no harmful effects and a host of benefits.18,25,26 The Japanese experience is shedding new light on the importance of iodine, not only for thyroid health, but on other body functions as well. In particular, compelling evidence is emerging about the role of iodine in maintaining breast health, a major concern for millions of American women.
Since thyroid function is a puzzle to many people, we’ll begin with a brief overview of that important gland and its requirements for iodine. Then we’ll turn to the role of iodine in maintaining breast health, particularly in preventing breast cancer and fibrocystic breast disease.
