Selenium intake and nutritional status of children with phenylketonuria in Minas Gerais, Brazil

Objective: To evaluate selenium dietary intake and nutritional status of patients with phenylketonuria. Methods: The study prospectively evaluated 54 children with phenylketonuria, from 4 to 10 years old. The study was performed before and after the use of a selenium-supplemented amino acid mixture. The second phase of the study was performed after, at least, 90 days of use of the supplementation. Selenium nutritional status was assessed through the analysis of biochemical parameters: serum free thyroxin and selenium and glutathione peroxidase in erythrocytes. Selenium dietary intake was evaluated by the administration of the Food Frequency Questionnaire. Results: Mean age of the children was of 7.0+/-1.8 years, and 35.2% were female. Mean time of supplementation of selenium, on special formula, was 122.2+/-25.1 days. The selenium-supplemented amino acid mixture represented 72.9% of the daily supply of the mineral. Upon supplementation, mean concentrations of serum selenium and glutathione peroxidase in erythrocytes increased significantly (p < 0.05). The average daily intake of selenium increased significantly (p < 0.001), reaching the levels recommended by the Dietary Reference Intakes. The concentration of free thyroxin, in serum, presented significant reduction (p < 0.001) in all patients during the second phase of the study, and returned to normal limits in those who had changed levels. Conclusion: Selenium supplementation through protein replacement is effective to improve and adapt the nutritional status of selenium in patients with phenylketonuria.