Iodine in plant-based and vegan diets

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Now that Veganuary is over, you might be toying with the idea of continuing with your new plant-based way of eating and planning exciting meals for the coming weeks.

But have you considered where you get your iodine from?

Iodine is an essential micronutrient needed to make thyroid hormones, which regulate many processes in the body like metabolism and growth. The recommended amount of iodine that adults should consume each day is 150µg (or 250µg if you are pregnant or breastfeeding, to support the healthy growth and development of your baby).

The main food sources of iodine in the UK are milk, dairy products, eggs, and (sea) fish. Excluding these foods from your diet means that you should pay close attention to the foods you choose instead to meet iodine intake recommendations. This is important to avoid the potential negative consequences of iodine insufficiency (such as thyroid dysfunction).

Vegan sources of iodine

Iodine-fortified milk alternatives

With such a huge selection of plant-based milk alternatives to choose from, opt for one that is fortified with iodine. Most milk-alternatives are not fortified with iodine so it is important to check the label and look out for ‘potassium iodide’ or ‘potassium iodate’ in the list of ingredients.

Iodised Salt

Salt is not routinely fortified in the UK, so switch your regular salt for iodised salt (look for the word “iodised” on the label or “potassium iodide/iodate” in the list of ingredients). Remember that the government recommends that adults shouldn’t have more than 6g of salt each day as high salt intakes are associated with increased blood pressure (hypertension).


The easiest and most reliable way of meeting your daily iodine intake goal is to take a supplement containing 150µg of iodine. Avoid seaweed-based supplements, especially those not telling you exactly the dose of iodine contained. Discuss the use of supplements with a healthcare professional to make sure they are suitable for you.


Seaweed is to be consumed with caution! Nori (Porphyra species) contains around 16 µg of iodine per gram. However, The iodine content of seaweeds is extremely variable and some seaweeds (especially kelps (Laminaria species)) can contain more than 8000µg of iodine per gram, which is dangerous for the thyroid.

Although seaweed can be a great plant-based source of iodine, remember to always check the label and don’t eat too much of it! 

Where to get more information

If you are still unsure about how you can meet iodine intake recommendations, you can seek personalised advice from a registered dietitian or AfN-registered nutritionist who can support you to ensure that your diet is healthy, balanced, and iodine replete.

Post by Martha Redway (PhD student at University of Glasgow) Feburary 2020


Image drawn by Martha Redway