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The Iodine Deficiency Problem: How Seaweed Could Help

Found in foods such as dairy, fish and other seafoods, iodine is a naturally occurring, and essential element of human nutrition. It is found in very limited amounts in land-based fruit and vegetables. Iodine is needed by the body to make thyroid hormones which manage the body’s metabolism and other important functions.

Diets insufficient in iodine can lead to Iodine Deficiency Disorder; the response to which is goitre (where the thyroid gland increases in size) and the potential for hypothyroidism. The Iodine Global Network reports the UK ‘now ranks seventh among the ten most iodine-deficient countries on the list’ as 76 percent of UK girls are iodine sufficient. This appears to be of growing concern around the world, and a recent report states iodine deficiency is no longer a third world issue.

There are six EU Approved Health Claims associated with the intake of iodine, including energy yielding metabolism, thyroid health, cognitive function and normal development of children. More than 50 percent of children and pregnant women in Australia are iodine deficient. During infancy, babies get their iodine from breast milk, but the levels of iodine depend on the mother’s intake. Mild and severe iodine deficiency can both have harmful effects on children’s brain development, nervous system and neurological development.

How can seaweed help iodine deficiency?

Seaweed is a natural source of iodine, as opposed to being a manufactured extract such as potassium iodide and added to salt or supplements, for example. Studies show consuming iodised salt or supplements containing potassium iodide may result in the iodine being excreted more quickly, whereas iodine from the right types of seaweed can be absorbed more slowly in a sustained way.

It is important to note while all seaweeds contain iodine, the levels of iodine differ vastly between different species. For example, Porphyra species contains around 0.118mg/g[i] iodine (79 percent RNI*) and Laminaria digitata species that contains 4.25mg/g (2,833 percent RNI*). Ascophyllum nodosum, however, contains 0.725mg/g (483 percent RNI*).  This diversity is important to understand depending on intake levels, and a supplier should always be able to advise and provide batch-by-batch iodine information.

Which seaweed will work for you?

The levels of iodine in Hebridean Ascophyllum are at moderate levels as compared to other seaweed, and well within recommended intake levels for the amounts that are used.  They are nowhere near as high as many of the ‘kelps’, which can often cause alarm and regulatory issues. 

Furthermore, Seaweed & Co. is leading an Innovate UK (the UK’s Innovation Agency) funded project looking at using our seaweed powders in pizzas and supplements as a natural source of iodine to seek to address the huge challenges of a population with a diet insufficient in iodine.


iValues from the Committee on Medical Aspects of Food and Nutrition Policy (1991)ii and the institute de Phytonutriton (2004)iii.

ii Committee on Medical Aspects of Food and Nutrition Policy. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Rep Health Soc Subj. (1991). 41:1–210

iii Institut de Phytonutrition. Functional, health and therapeutic effects of algae and seaweed. (2004). Institut de Phytonutrition electronic database. Version 1.5. Beausoleil, France, Institut de Phytonutrition.

*Based on RNI of 150mcg/day

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