In a situation analogous to zinc which I discussed in my last video, those eating healthy
diets centred on whole plant foods can potentially run into issues with iodine.
I've covered some other nutrients of concern for vegans in this series already and there
are a few more to come, so make sure you check out that playlist if you haven't already and
subscribe so you don't miss the rest of the series.
Feel free to let me know in the comments section below if there's any particuar nutrient you'd
like to see covered!
Vegans do not consume dairy, and a whole foods, plant-based diet minimises added salt.
These happen to be two of the primary sources of iodine in the developed World, dependent
on where you live - different jurisdictions vary in the degree to which salt is iodised.
Concerningly, this might not just be a vegan-specific problem - changing industry practices have
resulted in less iodine-based disinfectants being used in dairy production and hence less
iodine making it into dairy products, and it is estimated that overall around 2 billion
people Worldwide are at risk of iodine deficiency disorders.
In addition to the elimination of these two sources, healthy foods like raw cruciferous
vegetables, flax seeds and soy beans also contain phytochemicals that can interfere
with iodine utilisation in people with already marginal intake, potentially exacerbating
the problem for those eating healthy.
Indeed, when dietary intake levels are compared in surveys, vegans do appear to take in less
iodine on average due to all these factors, although this type of survey has some potential
flaws as we will see.
More tellingly, urinary iodine concentration is considered to be the best marker for iodine
intake on a population level, with levels over 100 μg/L considered to indicate sufficiency
- a level which vegans have been found to fall shy on.
Unfortunately, like with zinc, the iodine content of whole plant foods varies widely
depending on the soil in which it is grown, with vast swathes of land being iodine-deficient,
especially in mountainous regions and far from the sea.
Relying on commonly-consumed whole plant foods for iodine is a sure-fire way to run into
insufficient intake.
This intra-food variability of iodine concentration is why iodine content is not usually reported
on food labels, one of the reasons why estimating intake by questionnaires can be inaccurate,
and why apps like Cronometer do not enable it by default and warn you that if you do
track it, you are not likely to get an accurate intake level.
So if you've wisely decided to remove these unhealthy items from your diet, where are
you going to get your daily 150 μg of iodine?
Of the commonly consumed whole plant foods, potatoes and cranberries are the best sources,
but again this depends on where they are grown.
Foods in general grown near the sea tend to be higher in iodine.
However, the richest vegan-friendly source by a long way are those actually grown IN
the sea - the sea vegetables.
Some of the sea vegetables can provide many times the daily adequate intake level, and
since iodine can be stored in the thyroid gland these foods need only be eaten every
so often to provide enough iodine and an average intake of 150 μg per day.
However, the iodine concentration is highly variable between the different seaweeds, and
some of them are so highly concentrated that even small servings provide amounts well in
excess of the daily tolerable upper level.
Some of them are indeed only meant to be used in small amounts and as condiments, but it
is important to know the iodine content of whichever foods you choose to include.
With all this in mind, using sea vegetables is a great way to source iodine and many other
trace minerals on a vegan diet, but it takes a little bit of planning.
If you'd like to take this element of planning out of your diet or can't find any sea vegetables
you enjoy, I recommend a supplement containing 100% of the adequate intake level - 150 μg.
Some groups recommend all pregnant and breastfeeding women supplement iodine regardless of what
the rest of their diet looks like.
If you are going to supplement, I don't recommend kelp-based supplements since the dose of iodine
is not as standardised.
Since this nutrient doesn't spoil, I prefer liquid supplements to skip on the excipients
that would come with tablets.
Iodine is very absorbable, so the chemical form is not that important, though potassium
iodide is probably the best.
This is the one I am currently taking myself.
Iodine definitely appears to be an under-appreciated problem in vegans.
Dietary surveys don't tend to count sea vegetables when assessing dietary iodine intake, and
these surveys are prone to error anyway as we have seen.
Nevertheless, vegans consistenly appear to have lower iodine intakes, sometimes alarmingly
lower than the daily adequate intake level.
Yet this nutrient is not discussed as extensively as the likes of vitamin B12.
Regardless of how you intend to get your iodine, I strongly believe we need to pay attention
to this nutrient.
If you are eating a vegan diet and make no effort to source this element, it is likely
you will not be getting the adequate intake.
So to summarise, around 2 billion people globally may be at risk of iodine deficiency diseases,
largely due to insufficient iodine in soil used to grow food.
Vegans are partcularly at risk due to their exclusion of dairy.
Sea vegetables are the most reliable vegan-friendly food source, but are very variable in their
iodine content and using them as a source of iodine requires planning.
A potassium iodide-based liquid supplement is probably best if you choose to get your
iodine that way.
I hope this video was useful and gave you a better understanding of dietary iodine!
If there was something that wasn't clear from the video or you have any questions or comments
feel free to leave them in the comments section below and I'll get back to you.
Be sure to share this video with anyone you know who may be concerned about iodine and
hit that like button if you found this overview informative.
That's it for now though guys, talk to ye soon.
Sláinte!