Selenium (Se) in foods in northern Mexico, their contribution to the daily Se intake and the relationship of Se plasma levels and glutathione peroxidase activity

Abstract

Selenium (Se) is an essential trace element and a recommended daily intake for humans has been established. Se content in foods varies greatly by regions, depending upon soil conditions and certain agricultural practices. Se status in individuals is affected by diet and the availability of the Se. There is a lack of an uniform criteria to determine Se status leading to the use of Se values in plasma and whole blood as a reference. Se is an integral part of the important antioxidant enzyme, glutathione peroxidase and its activity in blood has been used to evaluate bioavailability of Se in food products. The objective of this study was to determine Se content in selected food products in northern Mexico and Se levels in plasma and GSH-Px activity in erythrocytes and plasma in different age groups in Hermosillo, Sonora, Mexico. Samples of seafood products, meat, poultry, eggs, milk, cheese, beans, corn, wheat, and corn and flour tortillas were randomly purchased in local stores and analyzed for Se by Atomic Absorption-Hydride Generator (AA-HG). Plasma Se was determined by the same method and GSH-PX activity by the oxidation reduction coupling reaction. Fish and seafoods, were found to be relatively high in Se and are major contributors of Se in the daily diet. Beans and corn tortillas are also important Se contributors and these foods along with flour tortillas are the main energy providers in the typical mexican diet. Total intake of Se appears to be quite adequate. However nothing is known about the bioavalability of the Se in the mexican diet. Se plasma values compare favorably particularly for children with other reported values and appear to indicate an adequate Se status in the population of this study.