Selenium and thyroid function in infants, children and adolescents

Area of Science:

• Endocrinology
• Nutritional Science
• Biochemistry

Background:

• Selenium is essential for glutathione peroxidase (GPx) and iodothyronine deiodinase enzymes.
• Thyroid function may be influenced by selenium nutrition, particularly in pediatric populations.
• Existing data suggest a modest impact of selenium deficiency on thyroid function.

Purpose of the Study:

• To review the role of selenium in thyroid hormone metabolism and function.
• To evaluate the effects of selenium deficiency and supplementation in various clinical scenarios.
• To provide guidance on selenium supplementation in conjunction with iodine therapy.

Main Methods:

• Literature review of studies on selenium, thyroid function, and related enzymes.
• Analysis of clinical data from patients with isolated selenium deficiency (e.g., phenylketonuria).
• Examination of epidemiological data from regions with combined selenium and iodine deficiencies.

Main Results:

• Isolated selenium deficiency impairs peripheral thyroid hormone metabolism but typically does not alter TSH or cause clinical hypothyroidism.
• In areas with dual deficiencies, selenium deficiency may contribute to thyroid gland destruction but can mitigate fetal hypothyroidism.
• Selenium supplementation may enhance tissue GPx activity, reduce oxidative stress, and optimize thyroid hormone feedback in specific conditions.

Conclusions:

• Selenium plays a complex role in thyroid health, with deficiency having a relatively modest impact in isolation.
• Selenium supplementation may be beneficial for optimizing antioxidant defenses and thyroid hormone metabolism in specific patient groups.
• Careful consideration of iodine status is crucial before advocating selenium supplementation, especially in endemic goiter regions.