At a glance
- Iodine is essential for energy regulation1 due to its role in the production of thyroid hormones.
- Deficiencies are commonplace in vegans, as the only major plant based source, seaweed, is unreliable.
What is the role of Iodine and do vegans get enough
Iodine is essential for the production of thyroid hormones, which play a major role in thyroid function such metabolism and your levels of energy.
Iodine contributes to the maintenance of normal skin, normal cognitive function, normal energy-yielding metabolism, normal functioning of the nervous system, the normal production of thyroid hormones and normal thyroid function and normal growth of children.
Studies have shown 80% of vegans suffer from iodine deficiency.1 This is mainly because the major sources of iodine are animal products, such as fish and milk, but also because vegans consume more foods containing natural chemicals called goitrogens.
Goitrogens interfere with iodine uptake into the thyroid gland, sources include Brussel sprouts, kohlrabi, turnips, rutabaga, radishes, cabbage, kale, and cauliflower.
The UK government recommends 140 mcg/day for everyone over 15 years old.
Looking at the upper safe limit, the World Health Organisation recommends a maximum 1100 mcg iodine. However, observations in Japanese culture, where average intake is estimated at 1200 mcg, suggest potentially some benefits of having more iodine in the diet, as they tend to have longer life expectancies and less cancer.
In some countries (not including the UK), iodine is supplemented via incorporation into ‘iodized salt’. Vegans get some iodine in vegetables, but the amount is generally quite low and depends on the soil.
Levels of iodine vary drastically in seaweed
Vegans determined not to supplement can get Iodine in seaweed, but that can be a fairly dangerous option, as there is a lot of variance in the amount of iodine in edible seaweed.
Scientist’s have observed levels of only 16 microg/g all the way to over 8000 microg/g in various forms of edible seaweed, which means overdosing and underdosing could be a problem with this stratergy.2
For this reason we provide the full UK governments recommended dose of 140 micrograms, which still leaves plenty of room for safely taking a bit more iodine from a vegan diet.