Q: I have an underactive thyroid gland and am taking Synthyroid, one pill a day. One of my friends thinks that I will not need to take the pills if I take extra iodine in my diet? Is this safe and a good idea?
A: There is a fringe group of naturopaths and doctors who advocate drinking Lugol’s iodine to supplement the natural iodine found in some food.
Their reasoning is that the thyroid gland needs iodine to manufacture the hormone thyroxin. People with low thyroxin levels in the blood have a condition known as hypothyroidism, which makes them tired, weak and sluggish with a low pulse rate and low metabolic rate leading to weight gain. They also have brittle nails and coarse, dry hair and feel cold even in warm weather.
The problem with this seemingly harmless idea is that the iodine will at first have a stimulating effect, which makes the person who takes the supplement feel better to start, but can be a sign that the gland is being dangerously overstimulated and will eventually fail to produce any thyroid hormone on its own.
This is a result of something known as the Wolff–Chaikoff effect. The precise mechanism for this phenomenon is not yet completely understood. Of course, if you have had your thyroid removed or it has ceased to function already, then you are wasting your time and efforts in taking iodine supplements. Iodine is not a completely safe mineral because too much can lead to heart attacks or epileptic seizures.
There used to be a condition known as “Derbyshire neck,” a swelling in the throat or a goiter, which was first noticed in the early 1800s in the United Kingdom county of Derbyshire. This area of the midlands was later found to be lacking natural iodine in the soil.
Today, iodine supplements are added to regular salt, so most people get plenty in their normal diet. Sea salt, cheese, beef, fish and eggs or vegetables such as spinach, kale and beans all contain natural iodine. The daily recommended dose is so small that it is measured in micrograms.
Iodine is also sometimes used externally as an antiseptic or to kill fungal skin or nail infections. It can burn if too concentrated, but it is safe to use on the skin diluted.
In your case, I suggest that you continue to take your medications as prescribed by your doctor. You will also need to have a blood test about once a year to determine if the dosage of thyroxin is still the correct one.