[Nutritional importance of selenium]

Area of Science:

• Biochemistry
• Human Nutrition
• Trace Element Metabolism

Background:

• Selenium is a vital trace element with a historical perception of toxicity.
• Its primary known function is as a component of glutathione peroxidase (GSH-Px).
• Dietary sources vary in bioavailability, with vegetable sources offering higher absorption.

Purpose of the Study:

• To review the biochemical role of selenium.
• To assess current dietary intake and plasma levels in Spain.
• To highlight the uncertainty surrounding recommended dietary allowances, especially for children.

Main Methods:

• Literature review of selenium's biochemical functions.
• Analysis of dietary selenium intake data for Spain.
• Comparison of plasma selenium levels in Spain with European averages.

Main Results:

• The highest selenium concentrations are found in protein-rich foods like meat and fish.
• Selenium from vegetable sources demonstrates greater bioavailability.
• Spanish selenium intake averages 221 µg/person/day, with plasma levels of 87 ± 14 µg/L, aligning with the European average.

Conclusions:

• Despite its essential role, recommended dietary allowances for selenium remain undefined for humans, particularly children.
• Current selenium intake and plasma levels in Spain are within the European average.
• Further research is needed to establish precise dietary recommendations.