Supplementation with iodine linked to thyroiditis, studies show
Over the past several months I have seen a number of patients who have been diagnosed as having the autoimmune illness known as Hashimoto's thyroiditis.
All of them had initially complained of fatigue and were treated by various nontraditional medicine practitioners. They were told that their thyroid gland was underperforming and that supplemental iodine was needed.
All were later diagnosed with Hashimoto's disease as well as hypothyroidism. Some of them were told to continue the iodine because that treated Hashimoto's disease (it does not). Unfortunately, their illness was probably caused by their increased iodine intake.
Hashimoto's thyroiditis was first described in 1912 by a Japanese physician, Hakaru Hashimoto. If left untreated, this form of thyroiditis eventually results in destruction of the thyroid gland.
Some may have symptoms of low thyroid hormone production or hypothyroidism even though their thyroid hormone levels may fall in the reference range.
Symptoms include fatigue, weight gain, bowel issues, poor sleep, depression and body aches. Hashimoto's thyroiditis affects about 5-6 percent of the U.S. population and is more common in women.
The diagnosis of Hashimoto's thyroiditis is made though common blood tests. Risk factors for Hashimoto's thyroiditis include excessive amounts of iodine.
Interestingly, Hashimoto's thyroiditis is uncommon in areas of the world where iodine deficiency is commonplace. In contrast, in areas of the world where there is more iodine in the diet, Hashimoto's thyroiditis significantly more common.
Several interesting studies conducted in China demonstrated that iodine supplementation in iodine-deficient parts of China significantly increased the risk and diagnosis of thyroiditis, possibly unmasking already existing subclinical cases. In the U.S., several studies have suggested that long-term supplementation with iodine, over the daily recommended dose of 150 micrograms per day, increases the risk of thyroiditis.
One older study (1998) in the European Journal of Endocrinology showed that some people with Hashimoto's thyroiditis, but not clinically hypothyroid, became profoundly hypothyroid by increasing the daily intake of iodine by only 250 micrograms per day.
Some sobering recent medical research, again out of China, indicated that in areas where large amounts of iodine can be found in the drinking water, the children have lower IQs. Early research has demonstrated that high levels of iodine are actually toxic to brain cells.
Iodine is critical for the production of thyroid hormones such as T3 and T4. Indeed, the number after the T indicates how many atoms of iodine are attached to tyrosine (T) to create thyroid hormones.
Iodine is naturally found in many seafoods and some fruits. However, too much iodine is not healthy. We are rarely iodine deficient. The typical American diet, even a low-salt diet, has a reasonable amount of iodine.
If multivitamins are also taken, any deficiency in the diet can be safely corrected. Be aware that many iodine supplements contain more than the daily recommended amount. Daily consumption of kelp can increase iodine intake by as much as 1,000 micrograms per day.
Excess of any supplement can result in adverse effects. Iodine enthusiasm is a prime example.
• Dr. Patrick B. Massey, MD, PH.D., is president of ALT-MED Medical and Physical Therapy, 1544 Nerge Road, Elk Grove Village. His website is www.alt-med.org.