Girls and their Goitres: Iodine Deficiency in the UK
Call it a passion, or call it a compulsion – I can’t help but notice goitres everywhere I go. I was watching the news the other night, and one of the news presenters had a wonderful goitre. On a recent trip to London, goitres were everywhere. Maybe this is because of the sheer number of people on the streets in London, maybe there is something specific about the diet in London (less fish, more soya milk, maybe?)
In any event, the number of goitres I see reflects a dismal situation in the UK, one that leads to much malaise, and one that is so easy to correct.
But before I get on to the politics, let me clear a few matters up.
Starting with ‘What is a goitre?’
A goitre is a swelling of the thyroid gland in the neck, located just under and to the sides of the voice box. It is most evident in girls and women, because we have smaller voice boxes. (And maybe because we are more likely to be faddy eaters??)
The thyroid gland produces thyroid hormones, which regulate a number of important biological functions, including our metabolism.
Iodine is a mineral that we get from our diet. It is essential for the proper function of thyroid hormones. If we do not get enough iodine from our diets, then the thyroid gland will swell up in an attempt to catch more iodine and make enough thyroid hormones. And goitres are usually far smaller, and more subtle, than in the image below.
This doesn’t mean that going out and getting lots of iodine is going to be a quick, easy way to lose weight, as some people mistakenly think. Iodine deficiency will only lead to an inadequate supply of thyroid hormones if your thyroid gland isn’t able to compensate properly by expanding, giving you a goitre. But, when I stop people with a goitre (I just can’t help myself!), they will often admit to feeling tired, feeling the cold and struggling with their weight. Maybe it’s just co-incidence, or selective observation on my part, but alongside the tell-tale goitre, these women often have thin hair, too.
Where does iodine come from?
Obtaining enough iodine from the diet is quite tricky because there are so few dietary sources. The main sources are fish and seafood, but this depends on what they have been fed. Wild fish get their iodine from seaweed and plankton, which are excellent sources of iodine. Farmed fish and seafood (think king prawns and most of our salmon) may contain less, as they will typically be fed feed meal or pellets.
Seaweed and kelp are good sources, but aren’t likely to feature on our menus that often.
Vegetables grown by the sea are also good sources, but most of what we consume today is grown in greenhouses and polytunnels. Samphire is good source, as it is grown by the sea. The samphire we can buy in the supermarket is cultivated however, and I haven’t been able to find out how it is grown, to assess whether it is still a good source of iodine. I will keep the sleuthing up, watch this space.
Milk can be a source of iodine. This is due to both traces of iodine in cattle feed and the use of sanitising products that contain iodine. Organic milk will contain less iodine, as the cows are grass-fed. This is not a reason to avoid organic milk though, as it is a much better source of omega 3 fatty acids. Eggs, too, can be a source of iodine, through the use of fishmeal and seaweed as poultry feed.
Do other factors matter?
Some medicines, chemical compounds (for example, in cigarette smoke – yet another reason, if one were needed, to pack it up. Now.) and dietary compounds can interfere with how we absorb iodine from our diet. Most notable among the dietary compounds are the thiocyanates, which are also known as goitrogens.
Thiocyanates are found in the brassica vegetables (but don’t stop eating these, they are an excellent source of many phytonutrients).
Another compound that may interfere with iodine absorption and utilisation are the isoflavones in soya products. Soya products are traditionally fermented in Asian cultures. Think tempeh and tofu. Fermentation may break down the isoflavones. Many of the soya products on the UK market, including soya milk, are not fermented. Considering that those avoiding dairy, whether from an intolerance or choice, will be drinking soya milk, we are left with a gaping iodine hole.
Why is this a problem in the UK?
Many, if not most, developed countries, fortify their diets with iodine. The most usual way is to add iodine to salt, so-called iodised salt. Salt is iodised in the US and in 18 out of 43 European countries. In Australia and New Zealand, it is mandatory to iodise yeast-leavened bread instead. In the UK, we have no compulsory iodisation programme. This has led to concern about iodine status, particularly if women have suboptimal iodine stays during pregnancy.
Why does it matter?
Quite aside from thyroid function, adequate iodine is important for the neurological development of babies during pregnancy. Deficiency in the mother can lead to developmental, cognitive and learning problems in the unborn baby, which can extend into childhood.
Which groups may be more at risk?
According to the Scientific Advisory Committee on Nutrition Statement on Iodine and Health (2014), young women are particularly at risk of iodine deficiency in the UK, particularly women from Asian and black ethnic groups. I suspect that deficiency in the groups reflects both sub-optimal iodine intake UK-wide, coupled with these groups not typically eating fish, and possibly avoiding milk.
So, what can you do?
Make sure you are getting enough iodine. Most adults need 150 micrograms per day. Luckily, we store iodine, so you don’t need to get enough every day, just as an average, say over a week. The table below gives you a few examples of the best dietary sources of iodine. Incidentally, I have just stumbled upon a dried seaweed snack, containing 122 micrograms of iodine per snack pack.
If you use soya products, stick to fermented products, such as tempeh and tofu (and nato, if you’re really brave).
What about iodised salt?
You can buy iodised salt in UK supermarkets. The only brand I have been able to find is Cerebos.
Cerebos will provide 11.5 micrograms of iodine per gram, or around 57.5 micrograms per teaspoon. This shouldn’t mean that you should start using lots of salt just to get your iodine, and from the amounts per teaspoon, you can see that using iodised salt will only work if you really are cooking everything from scratch. I use iodised salt, but make most things I eat, including baking my own bread and even chocolate.
And sea salt?
Unfortunately, although sea salt starts out with a high iodine content, much of this is lost during evaporation to make salt, and so sea salt is not a good source of iodine, unless it has been fortified with iodine after production. Unless the label specifically states “iodised”, assume that whichever salt you are using does not contain iodine.
A final note – spread the message. It breaks my heart when I point out goitres and women say “Oh, yeah, I had been feeling so tired lately.” It really is so easy to avoid this problem.