The findings were based on a survey of 520 females aged between 18 and 45.
Published in the British Journal of Nutrition, the study showed just 43% knew what the nutrient was and only 27% were aware iodine deficiency is a current public health concern in the UK and Ireland.
It found 41% of the women were not able to correctly pick out any health problem related to iodine deficiency.
The researchers from Ulster University in Northern Ireland are calling for increased efforts to improve women’s understanding of the mineral.
“As part of a larger public health policy to eradicate iodine deficiency, educational intervention should be considered,” they wrote. “Among women of childbearing age, targeted public health campaigns are warranted to increase iodine nutrition knowledge and intake.”
Most preventable cause of brain damage
Getting enough iodine before conception and during pregnancy is vital for the baby’s neuro-development and even mild to-moderate deficiency during pregnancy can impair cognitive development.
The World Health Organisation (WHO) says iodine deficiency is the greatest cause of preventable brain damage in childhood worldwide.
Traditionally public health efforts have focused on iodised salt programmes in less developed countries, yet this latest study shows women in Ireland are getting an average of just 152 micrograms (µg) of iodine a day.
This means almost half (46%) fail to meet UK and Northern Ireland dietary recommendations of 140 µg per day, which in itself is lower than recommendations from the likes of the WHO and the European Food Safety Authority (EFSA).
Yet greater knowledge of iodine was linked with higher intakes.
Dr Alison Yeates, research fellow in nutritional biochemistry at Ulster University and one of the authors behind the paper, told us they had been surprised to see such a significant association between knowledge of and consumption of iodine.
She said this brought home the need for an education campaign.
Breaking the taboo
Similar public health campaigns have been seen in the past for folic acid, too low pre- and post-conception levels of which can increase the risk of neural tube defects for babies.
Speaking with us last year about its folic acid campaign, Irish public health body Safefood said a major barrier was overcoming the perception that taking folic acid means a woman is actively trying to get pregnant.
Research has also highlighted the importance of taking iodine before getting pregnant to give it time to build up in a woman’s body.
Yeates said more research was needed on this, but said a similar taboo was likely to prove a challenge in educating women about iodine.
“Emphasising implication for future generations is the way to go with it,” she said, saying education could start at high school age and should include health workers speaking with women already pregnancy.
Yet what advice should be given to women?
There are six approved health claims for iodine in the EU covering:
- Normal cognitive function
- Normal energy-yielding metabolism
- Normal functioning of the nervous system
- Normal growth of children
- Maintenance of normal skin
- Normal production of thyroid hormones and normal thyroid function
How much is enough?
EFSA recommends pregnant and lactating women consume 200 µg of iodine per day, compared to 150 µg for adults generally.
The WHO recommends 150 μg for non-pregnant women and 250 μg for pregnant and lactating women.
Yet in the UK and Northern Ireland this is lower still with 140 μg a day recommended for all adults, without any suggested increase for pregnant and lactating women.
“We know, based on WHO recommendations, that is probably too low because of thyroid production. We do perhaps need to consider levels in the UK,” she said.
No iodine supplements available
Wholefood sources of iodine are sea fish and shellfish as well as cereals and grains.
Most women in this survey got most of their iodine from milk and dairy products.
Yet few were aware of this as a good source. Just 39% knew fish and seafood were the richest sources of iodine and only 9% identified milk and dairy products.
Yeates said women needed to be educated on these sources, adding higher fish consumption could play a significant role in boosting iodine intakes.
She said there were no pure iodine supplements available in the UK, with most supplements containing the mineral being multivitamins and mineral pregnancy mixes or marketed as kelp seaweed tablets.
The UK’s National Health Service (NHS) says most people should be able to get all the iodine they need though a varied and balanced diet.
It warns supplement users taking too much could be harmful for thyroid gland function.
Source: British Journal of Nutrition
Published online ahead of print, DOI: https://doi.org/10.1017/S0007114516003925
“Iodine knowledge is positively associated with dietary iodine intake among women of childbearing age in the UK and Ireland”
Authors: S. Maria O’Kane, L. Kirsty Pourshahidi, Kayla M. Farren, Maria S. Mulhern, J. J. Strain and Alison J. Yeates