Selenium (Se) is an essential trace element for human health, playing a crucial role in the function of several selenocysteine-containing enzymes. The global variation in Se status is significant, with many populations not consuming enough Se to support the maximal expression of these enzymes. Low Se intake can lead to suboptimal antioxidant protection, redox regulation, and energy production, contributing to health issues such as infectious and chronic diseases. Supranutritional intakes of Se, however, appear to reduce cancer risk. The food systems of most populations do not currently provide sufficient Se, and efforts are needed to increase Se intakes through soil fertilization, plant breeding, and fortification of foods. Se-enriched foods and supplements have been developed to enhance Se content, but consumer acceptance and proper labeling are necessary to ensure safe and effective use. The conclusion emphasizes the importance of increasing Se intakes to improve public health, particularly in regions with low Se status.Selenium (Se) is an essential trace element for human health, playing a crucial role in the function of several selenocysteine-containing enzymes. The global variation in Se status is significant, with many populations not consuming enough Se to support the maximal expression of these enzymes. Low Se intake can lead to suboptimal antioxidant protection, redox regulation, and energy production, contributing to health issues such as infectious and chronic diseases. Supranutritional intakes of Se, however, appear to reduce cancer risk. The food systems of most populations do not currently provide sufficient Se, and efforts are needed to increase Se intakes through soil fertilization, plant breeding, and fortification of foods. Se-enriched foods and supplements have been developed to enhance Se content, but consumer acceptance and proper labeling are necessary to ensure safe and effective use. The conclusion emphasizes the importance of increasing Se intakes to improve public health, particularly in regions with low Se status.