RESUMO
The treatment of phenylketonuria (PKU) patients constitutes a phenylalanine (Phe) intake restriction in their diet, which is achieved by adding a special Phe-free amino acid mixture to the diet. It has been reported that this diet could have some micronutrient deficiency. Several authors have also reported an increased oxidative stress or impaired antioxidant status in human and experimental PKU. Our project assessed the concentrations of retinol, alpha-tocopherol, coenzyme Q10, and anti-oxidized low-density lipoprotein (ox-LDL) antibodies in PKU children's plasma. It was found that retinol concentration in PKU children remains within the norm despite a low intake. The lower plasma alpha-tocopherol concentration in PKU children compared with normal children was associated with the lower level of antibodies against ox-LDL. This raises the question whether higher than observed circulatory alpha-tocopherol is indeed beneficial to lower plasma ox-LDL levels. Further studies are needed to explain the genetic factor in PKU patients (e.g., CD36/FAT polymorphism gene). The open clinical question is whether daily supplementation of alpha-tocopherol changes the PKU patients' level of antibodies against ox-LDL.