The Iodine Balance in Seaweed
In this third of a series of blog posts on the benefits of iodine in seaweed, we look at the importance of getting the right amount in our daily diets.
Too much of a good thing is not good for you, so they say. Too little as well. That's certainly the case for iodine.
Seaweed is a rich source of iodine. Long recognised as being essential to good thyroid function, as well as bringing a host of other health benefits, iodine naturally occurs in the more than 300 types of seaweed to be found on Ireland's coastlines. The balance is important, however, as too much or too little iodine can be linked to thyroid dysfunction.
Seaweed is a good choice of food for those who want to get their essential vitamins and minerals from sources other than meat. That makes sense, but to get our recommended daily allowance of iodine from seaweed, which type of seaweed do we choose, how much of it do we collect, and what is the iodine content before and after cooking that we absorb? Should we take one type on its own, or blend a variety of specific seaweeds like a fine whiskey? These are not easy questions to ask, especially since countries vary on their definition of lower and upper tolerable limits. For example, the upper tolerable limit of iodine in the UK is 600 micrograms per day. In the US, it's 1,100 micrograms per day, nearly twice as much.
To illustrate some of these challenges, here's the link to an abstract from a study published by a number of research bodies in South Carolina in the US who analysed a range of seaweed types. Entitled 'Variability of iodine content in common commercially available edible seaweeds', they collected samples of 12 of the most common dietary seaweeds available from commercial sources in the US, as well as harvester-provided samples from Canada, Tasmania, and Namibia.
The range of iodine content was enormous, from 16 micrograms per gram (+/-2 micrograms) in nori, to 8,165 micrograms per gram (+/- 373 micrograms) in one sample of processed kelp granules. Not only that, but even before harvesting the variation in the same type of seaweed was considerable. Two Namibian kelps had the lowest iodine content in sun-bleached blades (514 micrograms per gram, +/- 42 micrograms per gram), and the highest in freshly cut juvenile blades (6,571 micrograms per gram, +/- 715 micrograms per gram). As a further wrinkle in the difficulty of assessing iodine content in the end product that we eat, the researchers also noted that Iodine is water-soluble in cooking and may vaporise in humid storage conditions.
So, not straightforward then! As an aside, for those who like much more detail when they do their research, here's a really in-depth article on iodine from the US Department of Health and Human Services. And here are some important facts and figures you need to know.
We're pioneers in the addition of seaweed ingredients to food. Over the last few years we've tried different seaweed types, in different blends, in different foods, involving different cooking techniques and recipes. This experience has enabled us to develop dried and milled products from sustainable sources and stringent processes containing the right balance of goodness for baking, cooking and garnishing. The end result? Well, for example, 2 slices or about 100g of our seaweed soda bread containing smRt bake will give you 100% of your reference daily intake of iodine.