Selenium status in preschool children receiving a Brazil nut-enriched diet

The Brazilian Amazon region has selenium (Se)-rich soil, which is associated with higher Se levels in populations fed locally grown produce. Brazil nuts are a major source of dietary Se and are included with meals offered to children enrolled in public preschool in Macapá. The aim of this study was to examine Se intake and status of these children.

The Macapá group consisted of 41 children from a public preschool who received 15 to 30 g of Brazil nuts 3 d/wk. The control group included 88 children from the nearby city of Belém who did not receive Brazil nut-enriched meals. In both groups, school meals comprised ≥90% of the children's total food consumption. Selenium was assessed using hydride generation quartz tube atomic absorption spectroscopy in plasma, erythrocytes, nails, hair and urine. Dietary intakes (macronutrients and Se) were evaluated using the duplicate-portion method.

Both groups received inadequate intakes of energy and macronutrients. Selenium intake was excessive in both groups (155.30 and 44.40 μg/d, in Macapá and Belém, respectively). Intake was potentially toxic in Macapá on days when Brazil nuts were added to meals. Although biomarkers of Se exposure exceeded reference levels in the Macapá group, no clinical symptoms of Se overload (selenosis) were observed.

The inclusion of Brazil nuts in school meals provided to children with already high dietary Se intakes increased Se levels and may result in an increased risk for toxicity. As selenosis is associated with some chronic diseases, we recommend continued monitoring of Se intake and status in this population.