Iodine: Are You Getting Enough?
A Short History of Iodized Salt
Iodine (I2) is present in sea water, but not in sea salt. Why? Because it is volatile; it evaporates during the drying of the salt. In order to obtain iodized salt, potassium iodide (KI), which is much less volatile than pure iodine, must be added. Potassium iodide also has the advantage of having a less-pronounced taste and does not modify the colour of the salt (iodine varies in colour from violet to brown).
Iodized salt, the first functional fortified food, appeared in America in 1924 (it had already been in existence in Switzerland), to compensate for iodine deficiency, which used to be very frequent.
“Synthetic” or “Natural” Iodine?
Is iodized salt good for you? It is sometimes said that “synthetic” iodine (KI) of iodized salt is not as good as “natural” iodine (I2). Well, that’s not true. Once dissolved in the body, these two forms release the same ionic iodine (I−). Indeed, you read right: the same; it is identical. Then, a transporter in the intestine binds to the iodine (I−) and actively incorporates it into the organism.
Iodized Salt or Sea Salt?
However, if the ionic iodine (I−) is identical whether it originates from KI or I2, it is still necessary to take into consideration the other ingredients of the table salt. And no, not all table salts are the same! Even though the iodine they contain is well-absorbed, the other additional substances may not be good for you!
In fact, iodized table salt is often filled with anticaking agents such as aluminum trisilicate (yes, yes, they are making you eat aluminum!) or sugar.
When it comes to raw salts, such as sea or earth salts (e.g. Himalayan salt), they are richer in various minerals (such as magnesium) than table salt, which at the base is NaCl (sodium chloride).
What is the Best Source of Iodine?
The best sources of iodine are seafood: seaweed, fish, and shellfish.
How Much Iodine Should You Take?
In Canada, the recommended nutritional intake for an adult is 150 mcg (micrograms) of iodine per day. However, opinions are divided regarding this dosage. In fact, in the 2006 New England Journal of Medicine, a 400 mcg intake is suggested to obtain the desired health effects. It is well-known that in Japan, where people are large consumers of algae, food intake can easily exceed several milligrams (mg) per day. With the latest findings on the roles of iodine (cysts, breast cancers, salivary glands, and thymus), it can be assumed that recommended intakes will increase.
Health Canada recommends a maximum tolerable intake of 1,000 mcg (1 mg) per day. This does not prevent some doctors and therapists from recommending much higher dosages.
Is it Dangerous?
Higher intakes, as seen with the Japanese for example, are associated with a slight increase in hypothyroidism. Daily doses of around 20 mg (20,000 mcg) have been associated with the development of nodules in the thyroid.
Selenium is the mineral that works in tandem with iodine. So, if you increase your intake of iodine, make sure that you have enough selenium in your system as to not unbalance your iodine/selenium ratio. It is always best to consult a professional in supplementation before starting. Besides, if you think your iodine is too low, why not just eat seaweed regularly?
Here’s to your health!