Getting adequate Iodine from a plant based diet

Getting adequate Iodine from a plant based diet

What is Iodine and why is it important?

Iodine is an essential mineral which plays a key role in thyroid functioning and hormones. It is key for the development of the brain, especially during pregnancy as the foetus is developing. Low levels of iodine during pregnancy can result in lower IQ of your child, and is easily preventable if eating or supplementing adequately. Research into later years of iodine deficiency show swelling of the thyroid gland (known as goitre) and trouble learning (lower IQ and reading ability).

National Statistics

In the UK research suggests that as a nation, we have sufficient levels of Iodine. However, this is a blanket classification and does not give proportions of individuals with deficiency. For example, in the UK those who consume a vegan diet have shown to have low levels of iodine. As a nation the key food sources of iodine are fish (predominantly white fish), milk and dairy products. With many people turning to a plant based diet it is essential that they take an iodine supplement or consume fortified iodine products to get adequate amounts.

How much should I be getting?

Adults should have a supplement of 140-150ug per day and pregnant or lactating should have 240-250ug per day. Never exceed this amount.

Where can I get it from?

Many plant-based milks have started to fortify their products with iodine but it is essential to check before purchasing. Not all plant milks do fortify with iodine so do not assume. A 100ml of fortified plant milk can contain between 13-30ug of iodine.

It is also crucial to be aware that the amount of iodine in foods is variable. Seaweed is a key example and should not be taken as a supplement. Sea kelp is a very concentrated source of iodine and should not be taken in supplement form, or eaten as a main source. Excess iodine intake is as dangerous as too low intake so is recommended not to be consumed more than once a week (if this is something you do enjoy to eat). Nori has a much lower concentration of iodine but it is still important not to consume this too regularly. Iodine levels are not accurate and excess consumption can lead to excess iodine intake.

What about sea salt?

False information online reports that iodine is found in sea salt, rock salt, strawberries, potatoes and kidney beans. This is inaccurate and they have very low amounts of iodine. Across the world you can find iodized salt but availability in the UK is only around 20%. It will be more expensive than regular salt and as a nation we are advised to keep salt intake low. Therefore, relying on iodine from iodized salt is not advised.


If you are eating a diet which does not contain dairy products or fish you must be drinking iodine fortified plant milks, or taking an iodate or iodide supplement. Adults should have a supplement of 140-150ug per day and pregnant or lactating should have 240-250ug per day. If you have concerns that you are deficient or want to get checked, consult your GP to get a thyroid function test.

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