Iodine is one of those minerals we rarely think about, yet without it the thyroid simply cannot do its job. It is also one of the few nutrients where both too little and too much cause problems. Let us take a calm, honest look at what iodine is for, who genuinely runs short and whether a supplement makes sense specifically for you.
Does this sound familiar?
- You wonder whether you are getting enough iodine from your food
- You avoid iodised salt, dairy products or fish
- You have heard that iodine matters for the thyroid, but you are not sure whether you need a supplement
Why iodine matters
Iodine is the raw material the thyroid gland uses to make its hormones. Those hormones govern your metabolism, your energy, your body temperature and many other processes. So when iodine is missing, the gland cannot make enough hormones, however hard it tries.
A respected review describes how severe iodine deficiency leads to an enlarged thyroid gland (goitre) and to reduced function (Zimmermann and Boelaert, 2015). That is precisely why salt is iodised in many countries, and this single measure solved much of the problem worldwide.
The strongest evidence: pregnancy and brain development
This is where the evidence is most convincing. Iodine is especially important in early pregnancy, when the baby's brain is being built. A large joint analysis of data from more than 6,000 mother and child pairs found a link between the mother's iodine status in the first trimester and the child's later verbal IQ (Levie and colleagues, 2019).
The honest caveat the authors themselves make: the effect is on verbal intelligence, not on all kinds of intelligence, and it is linked mainly to the first trimester. But the direction is clear: adequate iodine during pregnancy matters for the developing brain. That is why women who are pregnant or planning a pregnancy are among the groups for whom iodine deserves special attention.
The balance that matters: both too little and too much do harm
This is the most important part, and it is exactly the part the adverts tend to skip. With iodine the relationship is U-shaped: both a shortage and an excess raise the risk. A large study and meta-analysis of nearly 70,000 participants found that both low and high iodine intake increase the risk of autoimmune processes in the thyroid compared with an optimal intake (Wang and colleagues, 2019).
In other words, more iodine is not automatically better. An excessive intake can harm the very gland you are trying to support. So iodine is not something to swallow in large amounts just in case, but a nutrient where the goal is enough, not maximum.
Caution: if you have a thyroid condition, do not start iodine on your own.
With an existing thyroid condition (overactivity, autoimmune thyroiditis and others) extra iodine can make things worse. In these cases you should only take it after testing and on your doctor's advice.
π‘ Did you know...
- Iodising table salt is among the most successful public health measures and wiped out widespread goitre in many countries.
- The main dietary sources of iodine are fish and seafood, dairy products and iodised salt.
- A baby's brain is most sensitive to iodine shortage precisely in early pregnancy.
- Iodine deficiency is making a comeback in some developed countries because of less iodised salt and changed eating habits.
Who is genuinely at risk
For most people who use iodised salt and eat a varied diet, iodine is usually sufficient. A 2022 review notes, however, that mild to moderate deficiency is making a comeback in some developed countries because of changed habits (Nutrients, 2022). Here is who is more likely to fall short:
- Pregnant and breastfeeding women - the need is higher and the baby's development is at stake.
- Vegans and vegetarians - without fish and dairy the main sources drop away.
- People who avoid salt or use only non-iodised sea salt.
- Those who rarely eat fish and dairy products.
With iodine the question is not "more or less" but "enough". For most people food does the job; for certain groups a supplement makes sense.
How much iodine is enough
The rough guidance from the World Health Organization is around 150 micrograms a day for an adult and around 250 micrograms during pregnancy and breastfeeding. The point of a supplement is to cover that need if your food does not, not to exceed it many times over.
π‘ How to use it: Take it according to the dosage on the pack, a sensible amount that covers your daily need. Do not combine several iodine sources at once. If you have a thyroid condition, are pregnant or take medication, consult your doctor before use.
Who are we to write about this
Cvetita Herbal has been working for over 10 years as a European manufacturer with over 1 million happy customers. That is exactly why we prefer to explain both sides of iodine to you, rather than selling you "the more the better". An informed choice is the better choice.
Potassium Iodide
Our Potassium Iodide delivers 200 micrograms of iodine per tablet, that is a sensible daily amount matched to your real need, not a mega-dose. It makes the most sense if you are in one of the at-risk groups and your food does not provide enough iodine.
What to realistically expect
If you are at risk: the supplement covers the need your food does not provide and supports the normal function of the thyroid gland.
If you already get enough: more iodine brings no bonus, and in excess it can even do harm.
If in doubt: with a thyroid condition or during pregnancy, consult your doctor before use.
What customers say
"I follow a plant-based diet and do not eat fish, so I keep an eye on my iodine. I take a sensible dose and feel reassured that I am covering the need."
- Gabrielle N.
"We only use sea salt at home and I realised it is not iodised. The supplement is the simple answer, without me overdoing it."
- Keith A.
Frequently asked questions
What is iodine for?
Iodine is the raw material the thyroid uses to make its hormones, and those hormones govern your metabolism and energy. A shortage leads to goitre and reduced function.
Do I need an iodine supplement?
For most people who use iodised salt and eat a varied diet, no. It makes sense during pregnancy, on a vegan diet or if you avoid salt, fish and dairy products.
Can too much iodine do harm?
Yes. The relationship is U-shaped - both a shortage and an excess raise the risk of thyroid problems. That is why the goal is enough, not maximum.
How much iodine a day?
Roughly around 150 micrograms for an adult and around 250 during pregnancy and breastfeeding, according to the World Health Organization. Do not exceed the recommended amount.
If you are in an at-risk group and your food does not give you enough iodine, a sensible supplement covers the need without you overdoing it. With a thyroid condition or during pregnancy, consult your doctor first.
GET POTASSIUM IODIDESources
- Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol, 2015. pubmed.ncbi.nlm.nih.gov/25591468
- Levie D et al. Association of maternal iodine status with child IQ: a meta-analysis of individual participant data. J Clin Endocrinol Metab, 2019. pubmed.ncbi.nlm.nih.gov/30920622
- Wang B et al. U-shaped relationship between iodine status and thyroid autoimmunity risk in adults. Eur J Endocrinol, 2019. pubmed.ncbi.nlm.nih.gov/31252413
- Iodine and iodine deficiency: a comprehensive review of a re-emerging issue. Nutrients, 2022. pubmed.ncbi.nlm.nih.gov/36079737
- Bath SC, Rayman MP. Iodine deficiency in the U.K.: an overlooked cause of impaired neurodevelopment? Proc Nutr Soc, 2013. pubmed.ncbi.nlm.nih.gov/23570907
Food supplement. It does not replace a varied diet and a healthy lifestyle. It is not a medicine and does not treat disease. With a thyroid condition, during pregnancy or breastfeeding and while taking medication, consult your doctor before use. Do not exceed the recommended dose. This information is for educational purposes and does not constitute medical advice.