What is iodine good for?
Role of iodine in thyroid function
Iodine is fundamental for thyroid function, as the thyroid gland requires it in order to produce several hormones that are critical for a healthy metabolism. Iodine deficiency can result in a condition known as hypothyroidism, which can result in a large array of health conditions.Iodine is also of fundamental importance during pregnancy and infancy, due to its role in brain development and bone growth.
Sources of iodine
Fortunately, most people obtain all the iodine they need from food, such as saltwater fish, dairy, and also seaweed, if you are so inclined.It's also available in the form of iodized salt, that you can buy in some shops, although this is something that you will need to find explicitly stated on the packaging or in the ingredient list.
In my personal experience, very few brands of salt are iodized, so you might need to go out of your way to hunt some down if you want some. Kelp supplements are also known for their iodine content.
Excess iodine
That said, you probably don't need to seek out iodized salt, or even iodine supplements, unless you know for a fact that you are in some way deficient.In fact, too much iodine can also have negative effects on your thyroid function, even resulting in conditions such as hyperthyroidism, so it is important to double check before starting to take any type of iodine supplementation.
Potassium iodide is an iodine tablet
Most iodine supplements, and iodised salt in many countries, use potassium iodide as the carrier, which means the useful nutrient on the label is iodine, in micrograms, not a meaningful dose of potassium.Take it as iodine, with a meal as you would any other iodine tablet, and do not add a second iodine source — kelp, another potassium iodide tablet, or a high-iodine multivitamin — on top without checking the total, because the thyroid is easy to overdo. If you already take a separate iodine supplement, potassium iodide is the same mineral in a different bottle, not a new one, and it is not a stand-in for a potassium citrate or chloride tablet.
High-dose potassium iodide for radiation emergencies is a licensed medicine, not a daily vitamin, and that protocol belongs with official public-health advice rather than with this planner.
When should I take iodine?
Iodine is generally recommended to be taken with a meal, to avoid any of the potential side effects commonly associated with taking some supplements on an empty stomach. There does not seem to be a particular time of day best suited for taking iodine, so feel free to take it at any time.
What does iodine combine well with?
Iodine with selenium, taken together, for thyroid function
Iodine is the raw material your thyroid gland builds its hormones from, and selenium sits inside the enzymes that convert those hormones into their active form and also protect the gland from oxidative damage. Taking an iodine source with a selenium source puts one nutrient on each side of that production line.What should I avoid taking iodine with?
Avoid taking iodine at the same time as chlorella, sea moss or kelp
All of these work in the same direction, providing a substantial amount of iodine, and taking more than one at the same time can push your iodine intake beyond safe levels. Ideally, you should only need one source of iodine in your daily routine, so check the labels for each one to see where they stand.What are natural sources of iodine?
If you are interested in obtaining your daily iodine through your diet, you can often find it in:
Seaweed is by far the richest source of iodine that we can incorporate into our diet, although the concentration will vary from one variety to the next.
For example, Kombu kelp can have as much as 3,000mcg of iodine per gram, while varieties such as Nori and Wakame can have between 15mcg and 70mcg of iodine per gram.
Who should avoid taking iodine?
Before taking iodine supplements, check with your trusted healthcare professional if any of the following apply to you:
- Thyroid conditions
Iodine is needed in a narrow band, and people with hyperthyroidism or hypothyroidism need to discuss with their doctor before taking any supplements that contain iodine. An autoimmune thyroid condition is where that band is narrowest, because both Hashimoto's disease and Graves' disease can be pushed by a sudden increase in iodine from eating kelp, taking a supplement or having a contrast scan that incorporates iodine. Multivitamin tablets are another potential source of iodine.
Remember to always discuss any vitamins or supplements with your trusted healthcare professional if you are suffering from any health conditions.
Possible side effects of iodine
Possible side effects from taking iodine supplements may include (but are not limited to) the following:
- Metallic taste
Too much iodine can disturb the thyroid, in either direction, which is why extra iodine on top of a diet that is already rich in it is worth evaluating before you start adding iodine supplements to your routine.
If you are experiencing negative side effects from taking iodine supplements, stop taking them immediately and reach out to your trusted healthcare professional.
Drug interactions with iodine
The medicines listed below are the ones most often named in interaction reports for iodine, but it is by no means a comprehensive list:
- Levothyroxine
- Lithium
Lithium
Iodine and lithium both change how the thyroid works, and can often interfere with eachother with undesired results.Levothyroxine
Likewise, iodine can interfere with levothyroxine's effect on the thyroid.If you are taking any prescription drugs or medication, check with your trusted healthcare professional before taking iodine supplements.
Can I take iodine while pregnant or breastfeeding?
Iodine needs rise to 220 mcg a day during pregnancy and 290 mcg while breastfeeding, because your baby's brain depends on your thyroid hormone in the first trimester. A serious shortfall has been linked with cretinism and impaired development, and a milder one with poorer school-age outcomes.
A prenatal with 150 mcg covers most diets, iodized salt helps, however highly concentrated sources such as kelp can shoot past the upper limit of 1,100 mcg in a single capsule, so make sure to review all the labels to have a full understanding of the exact dose you are taking.
Remember to always discuss any vitamins or supplements with your trusted healthcare professional while pregnant or breastfeeding, or while attempting to conceive.
What are deficiency symptoms of iodine?
Possible signs of iodine deficiency may include (but are not limited to) the following:
- Enlarged thyroid (goitre)
- Harm to the baby's brain development during pregnancy
Bear in mind that high-dose iodine supplements are not a gentle fix, as they can swing the thyroid in the other direction.
If you are experiencing abnormal symptoms, reach out to your trusted healthcare professional as soon as possible.
Where should I store iodine?
For optimal shelf life, it is recommended to keep iodine supplements stored in the cupboard. Always make sure the bottle or container is tightly closed, and kept away from sources of light, heat and humidity.
Iodine data sources & further reading
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