Controlled Diet in Phenylketonuria and Hyperphenylalaninemia may Cause Serum Selenium Deficiency in Adult Patients: The Czech Experience

Abstract

Phenylketonuria is an inherited disorder of metabolism of the amino acid phenylalanine caused by a deficit of the enzyme phenylalanine hydroxylase. It is treated with a low-protein diet containing a low content of phenylalanine to prevent mental affection of the patient. Because of the restricted intake of high-biologic-value protein, patients with phenylketonuria may have lower than normal serum concentrations of pre-albumin, selenium, zinc and iron. The objective of the present study was to assess the compliance of our phenylketonuric (PKU) and hyperphenylalaninemic (HPA) patients; to determine the concentration of serum pre-albumin, selenium, zinc and iron to discover the potential correlation between the amount of proteins in food and their metabolic control. We studied 174 patients of which 113 were children (age 1-18), 60 with PKU and 53 with HPA and 61 were adults (age 18-42), 51 with PKU and 10 with HPA. We did not prove a statistically significant difference in the concentration of serum pre-albumin, zinc and iron among the respective groups. We proved statistically significant difference in serum selenium concentrations of adult PKU and HPA patients (p = 0.006; Mann-Whitney U test). These results suggest that controlled low-protein diet in phenylketonuria and hyperphenylalaninemia may cause serum selenium deficiency in adult patients.

Evaluation of trace element and mineral status and related to levels of amino acid in children with phenylketonuria

“…In our study, the mean serum levels of Zn in both groups (HPA and AAM) were comparable with the levels found in previous studies (Procházková et al, 2013), and also the mean serum levels of Zn were significantly lower in phenylketonuric children compared with those of the controls. These values are consistent with the findings found in the literature (Fisberg et al, 1999).…”

“…The levels of Se in serum samples were found lower in AAM group compared to HPA group (Procházková et al, 2013). This finding also seems to be in parallel with reports of some authors (Procházková et al, 2013;Van Bakel et al, 2000).…”

Long-term treatment for hyperphenylalaninemia and phenylketonuria: a risk for nutritional vitamin B12 deficiency?

“…300-450 mg Phe/day) and 12-16 g/day (i.e. 600-800 mg Phe/day) in the food of HPA patients (5). In the Czech Republic, the RDI of vitamin B 12 for toddlers is 1 μg, 1.5-1.8 μg for children 4-9 years of age, and 2-3 μg for older children and adults.…”

“…The amount of FSMP prescribed was based on the age, sex, protein need, and Phe tolerance of each individual patient, which is defined as the highest Phe intake able to keep plasma Phe levels within the safe range (27). Recommended daily intake (RDI) levels of protein were as follows: 1.7 g/kg/day at 3 years, 1.6 g/kg/ day from 4 to 6 years, 1.4 g/kg/day from 7 to 9 years, 1.1 g/kg/day for 10-12 years, and 0.9 g/kg/day for adolescents and adults (5,28,29). The usual tolerated amounts of natural protein in the food of PKU patients is 6-9 g/day (i.e.…”

“…Moreover, some patients, particularly adolescents and adults, do not consume the recommended amounts of FSMP. Patients on this restrictive therapeutic dietary regimen are exposed to a range of nutritional risks, including deficiencies of protein, calcium, iron, zinc, selenium, vitamins A and B 12 , folate, vitamin D, essential fatty acids, and carnitine (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Vitamin B 12 is administered to PKU and hyperphenylalaninemia (HPA) patients as part of their FSMP because this diet prohibits the consumption of meat, egg yolks, milk, and shellfish.…”