New survey finds teenage girls in Ireland have adequate amounts of iodine in their bodies

Monday 26 March, 2018. A new survey of 14-15 year old girls on the island of Ireland has found they have adequate amounts of iodine in their bodies based on guidelines from the World Health Organisation (WHO). This is the finding from a new report commissioned by safefood titled Iodine status on the island of IrelandThe report also found that higher intakes of dairy products were associated with better iodine status. Over 900 teenage girls participated in the study which involved seven sampling points across the island.

The aim of the safefood research, undertaken by Queen’s University Belfast, was to compare current iodine status on the island with existing international data. The research also looked at identifying the dietary sources and other contributors to iodine status in young girls.

While iodine deficiency is rare in the Western world, it is an important mineral required in trace amounts for the production of thyroid hormones. These hormones are involved in many body processes including growth and regulating our metabolism. Iodine sufficiency in young women is especially important given the need for iodine for the development of a baby’s brain during pregnancy and early life.

Introducing the research, Dr Cliodhna Foley-Nolan, Director of Human Health and Nutrition, safefood said;

We now have up-to-date information on iodine status of young females on the island of Ireland. Reassuringly they have adequate levels of iodine in their bodies. While this is to be welcomed, the levels found were at the low end of the range identified as adequate by the World Health Organisation (WHO). We get sufficient iodine in a varied diet containing milk, dairy and fish and additional iodine should only be taken under medical supervision. It’s important that teenage girls and young women continue to consume these foods both because of their iodine content and also for their calcium content.”

Principal investigator, Professor Jayne Woodside, Queen’s University Belfast continued “We chose this population group because iodine is an essential nutrient and there were concerns this group weren’t getting enough from their daily diet. As well as looking at the current iodine status on the island, our research also examined iodine concentrations of milk samples collected during different seasons of the year. Milk is the most important source of iodine in the diet. No seasonal differences were found and higher intake of dairy products was associated with higher levels of iodine. Other sources of iodine in the diet include fish and shellfish, meat and poultry. The WHO also recommend that population iodine status is reviewed every 5 years.”

The report Iodine status on the island of Ireland" is available to download from the safefood website.

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Editor’s notes

Why is iodine important?

Iodine is a mineral this is important for health. It is needed to make the thyroid hormones. These hormones are needed for many body processes including growth, regulating our metabolism and for the development of a baby’s brain during pregnancy and early life.

Iodine – how much do I need?

The recommended dietary allowance for adults in Ireland is 130 micrograms of iodine per day (µg/day) (1) while the UK dietary reference for iodine is set at 140 micrograms per day for adults (µg/day) (2). This can usually be achieved from a healthy, balanced diet.

During pregnancy and when breastfeeding, women need more iodine in their diet so talk to your GP or trusted health professional first to find out how much you would need. While some multivitamins are a source of iodine, ALWAYS consult with your GP before taking a supplement while pregnant or breastfeeding.

What foods do I find Iodine in?

Iodine is found in a range of foods, the richest sources being fish and dairy products. White fish contains more iodine than oily fish. The actual amount of iodine in food varies according to a range of factors – this includes the iodine content of the soil, farming practices, fish species and seasons of the year. The figures in the table below are for guidance purposes only.

Should I be worried about iodine if I'm planning a pregnancy?

Women need more iodine in their daily diet during pregnancy and when breastfeeding. Talk to your GP or trusted health professional to find out how much iodine you need in your diet.

How can I get my iodine level checked?

Talk to your GP or trusted health professional about this. Most of us have sufficient amounts of iodine in our body but you may need to add to this if you’re pregnant or breastfeeding. Not having enough iodine or too much iodine in your body can have health consequences so it’s important to get the right advice from them, especially before you consider supplementing your iodine.

Is low iodine a cause of my hypo or hyperthyroidism?

Not having enough iodine or having too much iodine in your body can have health consequences so it’s important to talk to your GP or trusted health professional if you’re concerned about your current iodine levels.

Can I get iodine from sources like iodised salt?

The best way to get iodine into your diet is through the food you eat – a list of food-rich, healthy sources is shown below. Less than 5% of the salt sold in Ireland contains iodine which is why eating foods like dairy, fish and eggs is the recommended way to get adequate amounts of iodine in your body.

Iodine content in micrograms per portion of food


Portion (g)

Iodine (micrograms [µg]) per portion


Milk, whole



Yoghurt, plain



Cheese, cheddar



Fish and shellfish

Haddock, cooked



Cod, cooked



Salmon, cooked



Prawns, cooked



Eggs, meat, poultry and nuts




Meat, cooked



Poultry, cooked



Nuts, mixed



Iodine content of food sourced from (3)

Teenage girls and young women consume some of the lowest amounts of milk compared to other populations groups. One of the reasons appears to be a perception (4) that milk is "fattening". Fat-free/skimmed and low-fat/semi-skimmed varieties are available. Whole milk contains 4g fat per 100g. This is much lower than the cut off of 20g fat per 100g for a product to be called ‘high fat’. Healthy eating guidelines in UK and Ireland recommend all population groups to include dairy foods or fortified alternatives in their daily diet.


  1. Food Safety Authority of  Ireland. Recommended Dietary Allowances for Ireland 1999.
  2. SACN. SACN statement on iodine and health 2014 (PDF)
  3. Finglas PM, Roe MA, Pichen HM, Berry R, Church SM, Dodhia SK, et al. McCance and Widdowson’s The Composition of Foods, Seventh summary edition. Cambridge: Royal Society of Chemistry; 2015.
  4. A review of the Milk Supply Chain (safefood. 2008)