Does iodine gas released from seaweed contribute to dietary iodine intake

Thyroid hormone levels sufficient for brain development and normal metabolism require a minimal supply of iodine, mainly dietary. Living near the sea may confer advantages for iodine intake. Iodine (I2 )g as released from seaweeds may, through respiration, supply a significant fraction of daily iodine require- ments. Gaseous iodine released over seaweed beds was measured by a new gas chromatography-mass spec- trometry (GC-MS)-based method and iodine intake assessed by measuring urinary iodine (UI) excretion. Urine samples were obtained from female schoolchil- dren living in coastal seaweed rich and low seaweed abundance and inland areas of Ireland. Median I2 ranged 154-905 pg/L (daytime downwind), with higher values (*1,287 pg/L) on still nights, 1,145-3,132 pg/L (over seaweed). A rough estimate of daily gaseous iodine intake in coastal areas, based upon an arbitrary respiration of 10,000L, ranged from 1 to 20 lg/day. Despite this relatively low potential I2 intake, UI in populations living near a seaweed hotspot were much higher than in lower abundance seaweed coastal or inland areas (158, 71 and 58 lg/L, respectively). Higher values(150 lg/L were observed in 45.6% of (seaweed rich), 3.6% (lower seaweed), 2.3% (inland)) supporting the hypothesis that iodine intake in coastal regions may be dependent on seaweed abundance rather than proximity to the sea. The findings do not exclude the possibility of a significant role for iodine inhalation in influencing iodine status. Despite lacking iodized salt, coastal communities in seaweed-rich areas can maintain an adequate iodine supply. This observation brings new meaning to the expression ''Sea air is good for you!''