What is iodine and why do we need it?
Iodine is an essential mineral used by your body to make thyroid hormones, which play a key role in regulating metabolism and maintaining thyroid function.
These hormones are also crucial for growth and brain development during pregnancy and childhood. Ensuring adequate iodine intake supports a healthy metabolic rate and helps prevent thyroid conditions such as hypothyroidism (underactive thyroid) and overactive thyroid.
Both iodine deficiency and excessive iodine intake can lead to thyroid dysfunction.
How much Iodine do you need?
In the UK, the general iodine intake recommended for adults is 140 mcg (micrograms) per day and should not exceed the safe upper limit of 600 mcg. Requirements for pregnancy, breastfeeding and childhood are outlined in our information about different life stages, available at vegansociety.com/nutrition.
There are concerns that some groups of people in the UK are not meeting the recommendations for iodine intake including teenage girls, those who are pregnant or breastfeeding and people who do not eat fish or dairy products.
How do vegans get enough iodine?
Dietary planning or selective supplementation can help you meet your iodine needs on a vegan diet.
Most plant foods contain a low amount of iodine because it is not an essential mineral for their growth. The amount of iodine in plant foods also varies depending on how much iodine is present in the growing environment.
One exception to this is seaweed, which contains high amounts of iodine. Despite this, regular seaweed consumption is not recommended as a way to ensure sufficient intake because it contains highly variable amounts of iodine.
Iodised salt is available in many countries, but this is not a great option for ensuring adequate iodine intake. This is because public health authorities recommend that we should reduce salt intake.
Arguably, taking a daily supplement containing iodine is the most reliable way to ensure adequate iodine intake in your daily diet*. Choose supplements that list potassium iodide or potassium iodate as the iodine source. Iodine supplementation should not exceed 150 mcg per day.
The Vegan Society offers a daily vitamin and mineral supplement specifically designed for vegans, called VEG 1, which includes iodine, selenium, vitamin B12, and vitamin D, designed to support a healthy, balanced diet.
*If you have a thyroid disease, you should check with your GP before starting an iodine supplement.
Another option is to consume at least 500mL (half a carton) of an iodine-fortified milk alternative daily – around 25 mcg per 100 mL is a good level.
Iodine tips to take away
The following options are reliable ways of adding iodine to a vegan diet:
- Ensure a daily intake of around 500 mL of a fortified milk alternative that includes iodine.
- Use a daily supplement containing potassium iodide or potassium iodate.
Further information
For more information, including references used to create this web content, download our Iodine PDF resource
You might be interested in checking out the following webpages:
- Vegan diets and iodine: a vegan dietitian’s perspective.
- Life stages – including pregnancy, breastfeeding and different age groups.
The Vegan Society 2026. Review date: April 2029
Refrences
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British Dietetic Association (2019). Iodine: Food Fact Sheet; www.bda.uk.com/resource/iodine.html (accessed 16 April 2026)
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Committee on Medical Aspects of Food and Nutrition (1991). Dietary Reference Values for Food Energy and Nutrients for the United Kingdom London: HMSO.
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Leung AM & Braverman LE (2012). Iodine-induced Thyroid Dysfunction. Current Opinion in Endocrinology, Diabetes and Obesity, 19: 414–419
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Public Health England (2016). Government Dietary Recommendations. Government recommendations for energy and nutrients for males and females aged 1-18 years and 19+ years, https://assets.publishing.service.gov.uk/media/5a749fece5274a44083b82d8/government_dietary_recommendations.pdf (accessed 16 April 2026).
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Scientific Advisory Committee on Nutrition (2014). SACN Statement on Iodine and Health,www.gov.uk/government/uploads/system/uploads/attachment_data/file/339439/SACN_Iodine_and_Health_2014.pdf (accessed 16 April 2026)
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Teas J, Pino S, Critchley A & Braverman LE (2004). Variability of Iodine Content in Common Commercially Available Edible Seaweeds. Thyroid 14: 836–841