Selenium status in a Northern Irish pregnant cohort with iodine deficiency.


Mullan KR(1), McMullan P(2), Hunter A(3), McCance DR(2), Smyth P(4)(5), Bath SC(6), Rayman M(6), Woodside JV(7).
Author information:
(1)Regional Centre for Endocrinology and Diabetes Royal Victoria Hospital, Belfast, UK. [Email]
(2)Regional Centre for Endocrinology and Diabetes Royal Victoria Hospital, Belfast, UK.
(3)Regional Royal Maternity Hospital, Belfast, UK.
(4)University College, Dublin, Ireland.
(5)National University Ireland, Galway, Ireland.
(6)Department of Nutrition al Sciences, Faculty of Health and Medical Sciences, University of Surrey, Surrey, UK.
(7)Centre for Public Health, School of Medicine, Dentistry and Biomedical Science, Queens University, Belfast, UK.


Selenium and iodine are trace elements that are maximally concentrated in the thyroid. Iodine is a substrate for thyroid hormone synthesis, while the selenoproteins protect the thyroid from the oxidative stress incurred. We measured plasma selenium concentration in 241 pregnant women in 1st trimester, previously reported to have iodine deficiency. Mean age was 30.3 years (SD 5.4), BMI 26.2 kg/m2 (SD 4.9) and 53% reported taking supplements. Median urinary iodine concentration was 73 μg/L (IQR 37-122) (WHO recommendation, ≥150 μg/L). Mean plasma selenium concentration was 75 µg/L (SD 7.7) which is below the 80-125 µg/L reported to be optimal. Four-day food diaries revealed a selenium intake of 43 µg/day (SD 15.9), also below the 55-70 µg/day reported to be optimal. This is the first report of selenium status in pregnancy on the island of Ireland. The possible combined effects of iodine and selenium deficiencies in pregnancy merit further investigation.