Iodine Status: Is There a Public Health Issue on the Island of Ireland?
- Project start date: 1 November 2013
- Project status: Completed
- Project type: Food safety
- Discipline: Nutrition
- Principal researcher/s: Prof Jayne Woodside, QUB
- Collaborator/s: Dr Mullan, Consultant Endocrinologist, Professor Young, Centre for Public Health, QUB, Prof Albert Flynn, University College Cork, Prof Peter Smyth, UCD, Professor Tanya McCance, UU, Prof Mayne, National Newborn Bloodspot Screening Laboratory
Research objective
- To assess the iodine status (by measurement of urinary iodine concentration) of 14- to 15-year-old females from 7 sample sites across the island of Ireland.
- To investigate the environmental availability of iodine, during each sampling phase.
- To examine dietary and other determinants of urinary iodine status.
- To examine regional and seasonal variation in the iodine content of milk throughout the island of Ireland.
- To measure neonatal blood TSH on the island of Ireland.
- To investigate trends over time in neonatal TSH results.
Outputs
Research report
- Title: Iodine status on the island of Ireland
- Publication date: 1 March 2018
- Summary: An assessment of iodine status of teenage girls and infants on the island of Ireland.
- Findings:
- Teenage girls aged from 14 to 15 years living on the island of Ireland (IOI) have adequate amounts of iodine in their bodies, according to World Health Organisation guidelines. This is the case even in summer months, when iodine status is expected to be at its lowest.
- Although the results show that this population group had adequate amounts of iodine, it is important to note that the median value was at the low end of the range identified as adequate by the World Health Organisation.
- Findings confirm previous reports that higher intakes of dairy products are associated with better iodine status. Participants (n=6) who reported consuming soya-based drinks had the lowest urinary iodine concentration although numbers were small. Urinary iodine concentrations were not associated with self-reported intake or fish or eggs. Self-reported consumption of white fish, oily fish and shellfish once a week or more was low (23%, 20% and 3%, respectively).
- The thyroid-stimulating hormone (TSH) blood-spot test results of infants born in Northern Ireland between 2000 and 2014 also indicate iodine sufficiency.
- Continual population-level monitoring of iodine and intake of dietary sources of iodine remains important – the WHO recommends that this be reviewed every 5 years.
- There is no indication that fortification of food with iodine is required to improve the iodine status of this population group.
- There was no difference in iodine concentrations between organic and conventional milk samples tested; however, the number of organic samples collected was small (n=22).
- There was no difference between iodine concentrations of milk samples collected in spring or summer months compared with those collected in autumn or winter months.
- Recommendations:
- Promote the consumption of iodine-rich foods in the population to prevent iodine deficiency.
- As milk is one of the main sources of iodine within the UK and Ireland, further investigation of variations of geographical location and milk type (conventional, or non-organic, as against organic) is of interest. In particular, gathering information on specific farming differences within the milk production chain on the IOI is required to develop a greater understanding of the contribution of the food chain to iodine intakes.
You can download the report below.
Other outputs
Peer reviewed article
Mullan, K., Hamill, L., Doolan, K. et al. Iodine status of teenage girls on the island of Ireland. Eur J Nutr 59, 1859–1867 (2020). https://doi.org/10.1007/s00394-019-02037-x
