[Selenium, an essential and toxic element. Latin American data].

After a brief discussion of some of the aspects of importance, sources, deficiencies and excesses of selenium the great differences of ingestion between different countries are mentioned. Breast fed children from an area in Venezuela ingest 10 times the amount compared with children from Finland. Among sesame seed samples from 20 different countries used as Se indicators, the highest and the lowest values were found in those of Latin-American origin. With very few exceptions the highest and the lowest urinary and serum Se levels reported in the literature came from this region. The performance of more studies in Latin-America on Se is recommended. Urinary excretion and analysis of finger nails or egg-white of freely foraging hens could be used as suitable indicators.