Iodine Status over Two Decades: Influence of Seaweed Exposure

Area of Science:

• Nutritional Science
• Public Health
• Pediatric Development

Background:

• Iodine deficiency is a global concern impacting cognitive development.
• Ireland has a persistent borderline iodine status, with median urinary iodine (UI) levels below the WHO recommendation of 100 μg/L.
• Table salt iodization, a common preventative measure, is not widely adopted in Ireland.

Purpose of the Study:

• To assess the iodine status of the Irish population.
• To investigate the impact of seaweed-rich environments on iodine intake.
• To provide evidence supporting the implementation of Universal Salt Iodisation (USI) in Ireland.

Main Methods:

• Analysis of urinary iodine (UI) levels in schoolchildren and adult females across different geographical locations in Ireland.
• Comparison of UI levels in areas with varying seaweed abundance and proximity to the sea.
• Evaluation of existing iodine intake data over the past 20 years.

Main Results:

• The overall median UI in Ireland remains borderline (72.4 μg/L), indicating persistent iodine insufficiency.
• Individuals residing in seaweed-rich environments exhibit significantly higher UI levels (45.6% of schoolchildren, 43% of adult females) compared to those in low seaweed or inland areas.
• A notable percentage of participants in seaweed-rich areas exceeded the recommended UI levels, suggesting environmental iodine exposure benefits.

Conclusions:

• The findings highlight the inadequacy of current iodine intake in the Irish population.
• Exposure to seaweed-derived iodine, particularly through respiration, positively influences iodine status.
• Universal Salt Iodisation (USI) is recommended to ensure adequate iodine intake, especially for women of childbearing age, to prevent neuropsychological deficits in children.