History Of Iodine And Research On Iodine Deficiency Disorder

Global health experts announced (12/1/99) in a news conference in Bogota, Colombia that iodine deficiency continues to be a serious threat to global health, cautioning that problems far more serious than the enlarged thyroid known as a goiter can result.

While iodine deficiency disorder (IDD) is not a common problem in the U.S., it is on the rise in the U.S. as well. The October, 1998 issue of the Journal of Clinical Endocrinology and Metabolism reported that over the last 20 years, the percentage of Americans with low intake of iodine has more than quadrupled. the researchers indicated that this trend may necessitate concerted efforts to increase iodine levels in people at risk of deficiency. Earlier in this century, iodized salt almost wiped out iodine deficiency in the U.S. The first National Health and Nutrition Examination Survey (NHANES I), which took place between 1971 - 1974, found that just 2.6% of US citizens had iodine deficiency. The followup NHANES III survey, conducted between 1988 - 1994, found that 11.7% are iodine deficient. Of particular concern is the fact that the percentage of iodine-deficient pregnant women has increased from 1% in 1974 to 7% in 1994. Maternal iodine deficiency is particularly dangerous to a developing fetus.'' The researchers do not have a cause for the drop in levels, though it is suspected that reduced salt in the diet, plus a reduction in the use of iodine as a food ingredient, may be responsible.

Iodine Dficiency Disorder (IDD) ignificant public health problem in 130 countries. While remarkable measurable progress is being made through universal salt iodization, there are nearly 50 million people who are estimated to still be affected by some degrees of IDD-related brain damage.

It affects 740 million people a year. It causes brain disorders, cretinism, miscarriages and goiter. It is the world's single most important and preventable cause of mental retardation. And it is almost unknown. Equally unknown is the success in eradicating it. Calling it "one of our best kept secrets" the World Health Organization has rededicated itself to eliminating Iodine Deficiency Disorder through an intense programme of salt iodisation and iodine delivery within the next decade.

One-third of the world's population is estimated to be at risk of IDD. Since the passage of a special resolution at the World Health Assembly in 1990 and subsequent resolutions in 1992 and 1996, the Department of Nutrition for Health and Development (NHD) of WHO has worked tirelessly to establish iodisation programmes around the world.

Iodine is found in various foods, including seafood, small amounts of iodized salt, and vegetables grown in iodine-rich soils. Iodine-containing mist from the ocean is another important source of iodine, since iodine is absorbed by the skin. Iodized salt provides 76 micrograms (mcg) of iodine per gram of salt.

Strong iodine is used to treat overactive thyroid, iodine deficiency, and to protect the thyroid gland from the effects of radiation from radioactive forms of iodine. It may be used before and after administration of a radioactive medicine containing radioactive iodine or after accidental exposure to radiation (for example, from nuclear power plant accidents). It may also be used for other conditions as determined by your doctor.

Radioactive iodine (commonly called radioiodine) is a form of iodine chemically identical to nonradioactive iodine. Therefore, the thyroid gland, which takes up iodine to make thyroid hormone, cannot distinguish between the two. However, the nucleus of a radioactive iodine molecule has excess energy and gives off radiation that can have effects on the cells in which it is concentrated.

Radioactive iodine treatment of hyperthyroidism makes use of the thyroid gland's natural need for iodine to make thyroid hormone. The thyroid is the only part of the body that collects and retains iodine. In hyperthyroidism, the thyroid cells are over-stimulated and make larger amounts of thyroid hormone. The excess amount of hormones are secreted into the blood, and produce the symptoms of hyperthyroidism. When radioiodine is given, the thyroid gland cannot tell if the iodine is radioactive or not, and collects it in the normal way in proportion to the activity of the thyroid. Radioiodine thus accumulates in the cells that make thyroid hormone and remains there long enough to radiate the gland and to slow thyroid production. Radioiodine that is not retained by the thyroid gland is secreted rapidly by the body (within two or three days), primarily through the kidneys into the urine.

All hyperthyroid patients have an increase rate of metabolism which causes their bodies to burn up food more rapidly than normal. In many, appetite and food consumption are also increased. Because of individual differences in metabolism and appetite, some hyperthyroid patients lose weight, some maintain their weight, and some actually gain weight. When they are cured by any method of treatment, body metabolism decreases and food is burned more slowly. Appetite usually decreases as well, and most patients return to their prehyperthyroid weight. However, the increased appetite may persist longer than the increased metabolism. If this happens to you, there may be a tendency for you to gain weight unless you voluntarily decrease your food intake. However, this can be readily controlled by decreasing food intake.

This form of treatment of hyperthyroidism by radioiodine has been used routinely for more than 35 years on well over one million patients in the United States alone. Many studies of people treated and examined at a later time show no harmful side effects or complications to the patients or their offspring. Radioiodine is now recognized as the safest, least expensive, and most convenient and effective treatment for hyperthyroidism. In the United States approximately 90 percent of hyperthyroid patients are treated with radioiodine.

In view of its safety, convenience, low cost, and effectiveness, most hyperthyroid patients and their physicians in the United States select radioiodine as the definitive treatment of choice.

  • World Health Organization sets out to eliminate iodine deficiency disorder (WHO/99-WHA17) 25 May 1999
  • U.S. National Library of Medicine, MEDLINEplus, Iodine, Strong
  • David V. Becker, MD, James R. Hurley, MD, and Ronald Detres. Radioactive Iodine Treatment of Hyperthyroidism

Discuss It!

Pat said:

so how did we get proper levels of iodine 200 years ago. How can this deficiency be all over the world?