Iodine in a Vegan Diet

What are the best vegan iodine sources and why is it important that we get enough?

Credit: Pixabay

What is Iodine?

Iodine helps make the thyroid hormones, which keep cells and the metabolic rate healthy. There is some concern that many people, vegan or not, are not getting adequate iodine in their diet.

iodine in the diet

Non-vegans in the West tend to get most of their iodine from milk, but it’s not a natural component of dairy. In fact, the majority of iodine in milk is due to contamination with the iodine-based disinfectant used to clean the cows’ teats and the milking machinery. 

vegan sources of iodine

Grains, nuts and vegetables contain some iodine, but levels vary widely depending on the soil the plants were grown in, which means there is no way of knowing how much we are getting. Even if grown in the most iodine-rich soils, we still may not get a sufficient amount.

Vegans can also obtain iodine from seaweed, but again, levels vary depending on the type, the seas from which it was harvested and whether it is cooked, but eating seaweed several times a week may be sufficient.

Although iodised salt is available, this is not the best option as data widely suggests most of us need to reduce our salt intake.

The most simple and reliable way to get enough iodine is to take a 140mcg supplement every day.

too much iodine?

We are warned against taking too much iodine as this could also cause problems. Some seaweeds, like kombu (kelp), contain much higher amounts, and we would do well to limit our intake of those.

The NHS advises that taking 0.5mg or less a day of iodine supplements is unlikely to cause any harm.

This page was reviewed by Claire Lynch, RD and nutritionist Rohini Bajekal from Plant-Based Health Professionals in November 2023. For more information, see the Plant-Based Eatwell Guide.

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