Nutritional status of patients with phenylketonuria in Japan

Abstract

Accumulating evidence suggests that hyperphenylalaninemia in phenylketonuria (PKU) can cause neuropsychological and psychosocial problems in diet-off adult patients, and that such symptoms improve after resumption of phenylalanine-restricted diet, indicating the need for lifetime low-phenylalanine diet. While limiting protein intake, dietary therapy should provide adequate daily intake of energy, carbohydrates, fat, vitamins, and microelements. We evaluated nutrient balance in 14 patients with classical PKU aged 4–38 years. Approximately 80–85% of the recommended dietary allowance (RDA) of protein in Japanese was supplied through phenylalanine-free (Phe-free) milk and Phe-free amino acid substitutes. Nutritional evaluation showed that the calorie and protein intakes were equivalent to the RDA. Phenylalanine intake was 9.8 ± 2.2 mg/kg of body weight/day, which maintained normal blood phenylalanine concentration by the 80% Phe-free protein rule. The protein, fat, and carbohydrate ratio was 9.5:23.9:66.6% with relative carbohydrate excess. Phe-free milk and amino acid substitutes provided 33.7% of carbohydrate, 82.1% of protein, and 66.7% of fat intake in all. Selenium and biotin intakes were 25.0% and 18.1% of the RDA and adequate intake (AI) for Japanese, respectively; both were not included in Phe-free milk. PKU patients showed low serum selenium, low urinary biotin, and high urinary 3-hydroxyisovaleric acid in this study. The intakes of magnesium, zinc, and iodine were low (71.5%, 79.5%, and 71.0% of the RDA, respectively) and that of phosphorus was 79.7% of the AI, although they were supplemented in Phe-free milk. PKU patients depend on Phe-free milk and substitutes for daily requirement of microelements and vitamins as well as protein and fat. Development of low-protein food makes it possible to achieve the aimed phenylalanine blood level, but this lowers the intake of microelements and vitamins from natural foods. The dietary habits vary continuously with age and environment in PKU patients. We recommend the addition of selenium and biotin to Phe-free milk in Japan and the need to review the composition of microelements and vitamins in A-1 and MP-11 preparations.

Fenilketonüri Hastalarının Beslenme Alışkanlıkları ve Besin Tüketim Düzeylerinin Değerlendirilmesi

“…Bu hastalardan 24 hasta (%21,6 ) yüksek okulda, 14 hasta (%12,6) üniversitede eğitim görmekteydi. 1 hastanın hangi okulda devam ettiği belirtilmemiştir (25). Bu çalışmayla karşılaştırıldığında, çalışmamızda eğitimine devam eden hastalar Bridget ve arkadaşlarının yaptığı fenilketonüri hastası ergenler ve yetişkinlerde düşük fenilalaninli diyetin değerlendirildiği bir çalışmada, erkek hastaların plazma fenilalanin değerleri ortalaması 770 ± 217 μmol/L, kadın hastaların plazma fenilalanin değerlerinin ortalaması ise 658 ± 337 μmol/L olarak bulunmuştur.…”

Growth and Nutritional Status of Phenylketonuric Children and Adolescents

“…In these patients, low levels of antioxidant micronutrients have been linked to poor mental function and psychosocial issues (22). In recent years, limited studies have examined the nutritional status of these patients (10,23,24). Some studies have examined the status of macro-and micronutrients (25-28), and few have analyzed anthropometric indices and body composition (29)(30)(31)(32).…”

Growth and Nutritional Status of Phenylketonuric Children and Adolescents

“…Consequently, anthropometric indicators, clinical indicators of nutrient deficiency, nutrient intake, and biomarkers to identify excess or lack of nutrients are needed for nutritional follow-up [26]. In recent years, limited studies have examined the nutritional status of these patients [12,27,28]. Some studies have examined the status of macro-and micronutrients [29][30][31][32], and few have analyzed anthropometric indices and body composition [33][34][35][36].…”