Tired? Struggling to lose weight? You might be missing something…

Did you know that most New Zealanders are mildly iodine deficient?

I was speaking at a conference last week, as I often do about living a happier, healthier life! As part of my presentation I decided to touch on some of the ‘little things’ which have a BIG impact, these being some of the vitamins and minerals us Kiwis often aren’t getting enough of – B vitamins, vitamin D, selenium, iodine, calcium and iron being just a few examples.

Most people at the conference identified that one reason why we don’t get enough iodine in our diets is because our soil here in New Zealand is lacking in iodine. But when I asked what iodine did or what they might need to eat to get more (other than add more iodised salt to their food) – blank faces!

So… today, a mini 101 on iodine for you! You might be thinking – really? Do I need to care about one little mineral? Well, yes you do! Iodine deficiency can affect hearing, intelligence and mental capability (hence why women now need to take an iodine supplement during pregnancy). Iodine deficiency can also result in goitre (which is a swelling of the thyroid gland in the neck) and that is definitely not good. This amazing little mineral is also vital to help you make thyroid hormones, which control your metabolic rate and in turn can affect your weight!

So, tune in – this is relevant to you, your friends and your family. Oh, and I promise not to get too geeky on you – let’s keep this practical!


Iodine is a mineral which is vital for growth and development – you can’t do without it, your body cannot make it by itself, so you have to get it in your food. It is essential for normal brain development and so it is particularly important for unborn babies, as well as for young children. As mentioned previously, it is also needed to make thyroid hormones.

You find iodine naturally occurring in fish, shellfish and seaweed. It is also found in eggs, milk (but far less than there used to be due to a change in processing), sea meal custard (which has seaweed in it), bread (as iodised salt is used) and of course – iodised salt itself.

The amount of iodine in your fruit, veges and grains very much reflects the soil in which it is grown and as you may know, here in NZ our soil doesn’t have much in it at all – so our fruit and veges, as well as other crops, don’t have much iodine in them either. The same goes for the iodine content of meat, fish, chicken and milk – it all depends on whether the animal feed used has iodine in it or not.

How much do we need?

The recommended daily intake (and this is to prevent deficiency) is 150μg per day. For optimal health and well-being, more may be helpful – the upper limit is 1110μg per day. So you can see, there is a lot of room to move. (For other ages see here.)

Now, given that in New Zealand the entire adult population are considered to be mildly iodine deficient, we have work to do!

How to UP the ante on iodine

Back in 1924 iodine was added to salt because of the issues arising in NZ with iodine deficiency – given that back then people made a lot more food themselves and were using iodised salt when they did so, it really made a difference.

The issue now though is that we eat so much processed food (in fact, around 75 per cent of our salt per day is already in foods that we buy like cereals, soups, crackers etc) and this salt is NOT iodised. Bread is really the only food which has iodised salt added to it, and if you don’t eat much bread – you won’t be getting the benefit from that either.

Yikes – yes, yikes indeed! So what can you do?

Well, first of all, where you can, limit the amount of heavily processed foods; and when you make food yourself, where you are using salt, use iodised. Soups and cooking sauces (for pasta, curries etc) are a good easy place to start – and really look to avoid those ‘packet flavour mixes’ for bolognese/chilli etc as they are LOADED with salt and none of it iodised. Start checking the back of your food labels, we are looking to have less than 2300mg sodium per day – you will be HORRIFIED when you see the levels in some of the food you eat!

The trend towards using ‘fancy’ salts which aren’t iodised has been yet another thing that has impacted on our intake of iodine. This is not to say you need to start throwing salt on all your food, as we eat far too much salt as a nation anyway. All I am saying, is look to reduce the amount of foods you buy which have added salt, see what you can make yourself, and where you use salt (and less is better) use iodised.

The other way to increase your iodine intake is by including other foods in your diet which have plenty (without having to up your salt) – this is by far the best option!

Everyday foods that contain iodine

  • 1 cup of trim milk = 17μg (trim has more than light blue or blue)
  • 1 egg = 23μg
  • 2 slices of wholegrain bread = 28μg


  • 4 mussels = 74μg
  • 2 oysters = 30μg
  • 100g canned tuna = 13μg
  • 100g canned sardines = 23μg
  • 100g canned salmon = 27μg
  • nori sheet (seaweed) = 68μg

How to include more seafood and seaweed

When it comes to BBQ season – don’t just rely on meat, try seafood! Mussels are super-cheap, too.

Canned fish makes a good option for lunch with a big salad or on a slice of wholegrain toast (which of course has iodised salt in it!).

Nori (that is just using the seaweed sheets that are used to make sushi) is probably one of the easiest ways to address iodine. You can tear up a sheet and add it to a salad, put some into a soup or you can use them like wraps – put some salad, hummus or avocado and protein like chicken, salmon or tuna for example – then wrap and eat!

If you think you might be very low on iodine, come and see one of my team at Mission Nutrition. We can help make sure you are getting all the nutrition you need and address the other vital vitamins and minerals at the same time.

Until next time… happy healthier living.

Love, Claire x

Claire Turnbull, BSc (Hons) Dietetics UK, NZ-registered nutritionist. Managing director of Mission Nutrition, and Healthy Food Guide nutritionist.

First published: Oct 2013

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