Endocrine Abstracts

JOINT1775

Background: Iodine and selenium are essential micronutrients for thyroid function, metabolism, and neurodevelopment. Deficiencies remain a global public health concern, particularly in regions with low soil iodine and selenium content, including Lithuania. While salt iodization programs have helped mitigate iodine deficiency, complementary strategies such as biofortified foods are needed to improve dietary intake. Eggs, widely consumed across populations, can serve as an effective vehicle for iodine and selenium delivery when hens’ feed is fortified. This study assessed the short-term impact of consuming iodine- and selenium-fortified eggs on urinary iodine (UIC) and selenium (USeC) excretion in adults following a low-iodine and low-selenium diet.

Methods: A randomized, double-blind, controlled trial was conducted at Vilnius University, Lithuania, enrolling 130 healthy adults aged 18–45. Participants were randomly assigned to consume either one iodine- and selenium-fortified egg (intervention group) or one standard egg (control group) per day for five days while adhering to a diet low in iodine and selenium. Spot urine samples were collected at baseline (day 0), day 3, and day 5. Urinary iodine/creatinine (UI/Cr) and selenium/creatinine (USe/Cr) were calculated for urine dilution. Daily urinary iodine excretion (UIE) and selenium excretion (USeE) were estimated using the Kawasaki formula. Iodine deficiency was defined as UI/Cr <100 μg/gCr and selenium deficiency was defined as USe/Cr <25 μg/gCr. Participants were included in the analysis if their urinary creatinine level was ≧20 mg/dL (iodine and selenium analysis) and if their CKD-EPI albuminuria category was A1 (selenium analysis). Statistical analyses included Student’s t-tests and paired t-tests.

Results: At baseline, 74.8% of participants were iodine deficient (UI/Cr: 80.73±34.74 μg/gCr), and 93.3% were selenium deficient (USe/Cr: 17.16±4.91 μg/gCr). By day 5, UI/Cr was significantly higher in the intervention group compared to the control group by 17.06 μg/gCr (93.41±44.43 μg/gCr vs. 76.35±36.74 μg/gCr, P=0.036), and UIE was higher by 31.83 μg/24h (161.85±84.60 μg/24h vs. 130.02±61.09 μg/24h, P=0.031). For selenium, USe/Cr increased by 1.09 μg/gCr in the intervention group (P=0.077) and by 1.41 μg/gCr in controls (P=0.075) compared to baseline. USeE increased significantly in the intervention group by 2.13 μg/24h (from 30.01±8.64 μg/24h to 32.14±11.04 μg/24h, P=0.047), but no significant changes were observed in the control group.

Conclusion: Consumption of iodine- and selenium-fortified eggs significantly increased urinary iodine excretion, while selenium changes were modest. These findings support fortified eggs as a promising approach to improving iodine and selenium status. Further research is needed to assess long-term effects and scalability.