Centro de Genética Médica, Centro Hospitalar do Porto (CHP), Porto, Portugal.
Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto-UMIB/ICBAS/UP, Porto, Portugal.
Eur J Clin Nutr. 2017 Oct;71(10):1230-1234. doi: 10.1038/ejcn.2017.38. Epub 2017 Apr 12.
BACKGROUND/OBJECTIVES: Low phenylalanine (PHE), glycomacropeptide-based protein substitute (GMP) is an alternative to traditional L-amino acid supplements (AA) used in the dietary management of phenylketonuria (PKU). In a retrospective, longitudinal study, we report the nutritional status of PKU patients taking AA and GMP.
SUBJECTS/METHODS: Eleven PKU patients aged 27±10 years (1 HPA, 4 mild and 6 classical PKU) on dietary treatment were evaluated (anthropometry, body composition, blood pressure measurements, biochemical markers including vitamin, mineral, lipids, carbohydrates and protein status/metabolism, and nutritional intake assessment) at two different annual reviews. The mean time taking AA was 13±5 months and GMP 13±7 months. Blood phenylalanine (PHE) and tyrosine (TYR) were analysed before and after GMP introduction.
Both GMP and AA protein substitutes provided similar protein equivalent intake (0.85 vs 0.75 g/kg/day, P=0.182). In the GMP group, it contributed 57% (27-100%) of the protein substitute intake (with AA delivering the rest of protein substitute intake), providing an additional 34±12 mg/day PHE. Nutritional intake, anthropometry and body composition measurements were similar in both the groups. Median blood PHE did not change (P=0.594), although values within target range improved (36 vs 46%), but this was not statistically significant. Mean blood TYR increased (52.0±19.2 vs 63.2±25.6 μmol/l, P=0.033), and all biochemical markers remained stable, except for a lower A1C haemoglobin (P=0.011).
Partial GMP contribution to total protein substitute intake did not affect nutritional status in patients with PKU. Blood PHE control was not adversely affected. The increased blood TYR after GMP introduction necessitates further study.
背景/目的：低苯丙氨酸（PHE）、糖巨肽基蛋白替代物（GMP）是苯丙酮尿症（PKU）饮食管理中替代传统 L-氨基酸补充剂（AA）的一种选择。在一项回顾性、纵向研究中，我们报告了使用 AA 和 GMP 的 PKU 患者的营养状况。
研究对象/方法：对 11 名年龄 27±10 岁（1 名 HPA、4 名轻度和 6 名经典 PKU）的 PKU 患者进行了评估（人体测量学、身体成分、血压测量、生化标志物，包括维生素、矿物质、脂质、碳水化合物和蛋白质状况/代谢以及营养摄入评估），在两次年度审查中进行了评估。使用 AA 的平均时间为 13±5 个月，使用 GMP 的平均时间为 13±7 个月。在引入 GMP 前后分析了血液苯丙氨酸（PHE）和酪氨酸（TYR）。
GMP 和 AA 蛋白质替代品提供了相似的蛋白质当量摄入量（0.85 与 0.75 g/kg/天，P=0.182）。在 GMP 组中，它提供了蛋白质替代物摄入量的 57%（27-100%）（AA 提供了其余的蛋白质替代物摄入量），每天额外提供 34±12 mg PHE。两组的营养摄入、人体测量学和身体成分测量均相似。中位血 PHE 未发生变化（P=0.594），尽管目标范围内的值有所改善（36 与 46%），但无统计学意义。平均血 TYR 升高（52.0±19.2 与 63.2±25.6 μmol/L，P=0.033），所有生化标志物均保持稳定，除 A1C 血红蛋白较低外（P=0.011）。
GMP 对总蛋白质替代物摄入量的部分贡献并未影响 PKU 患者的营养状况。血液 PHE 控制未受到不利影响。引入 GMP 后血液 TYR 的增加需要进一步研究。
