Simplified Diet for nutrition management of phenylketonuria: A survey of U.S. metabolic dietitians

Abstract

Background Phenylketonuria (PKU) is an inherited metabolic disorder affecting the conversion of phenylalanine (Phe) to tyrosine. Medical nutrition therapy, consisting of a Phe‐restricted diet with medical formula, is the primary treatment for PKU. The Simplified Diet is an approach to PKU nutrition management that allows certain fruits, vegetables, and low‐protein foods to be eaten without measuring or tracking, referred to as free/uncounted foods. There is no consensus on how to implement this approach in metabolic centers in the United States (U.S.), and clinical practice varies. Aim This study describes the clinical experience of metabolic dietitians in U.S.‐based metabolic centers related to the use and implementation of the Simplified Diet. Methods A survey was developed and sent out to metabolic dietitians to query current clinical practices related to the Simplified Diet. Descriptive statistics were used to analyze responses. Results Sixty‐three dietitians managing ≥5 patients with PKU in U.S.‐based metabolic centers responded to the survey. Ninety‐eight percent of survey respondents reported using some version of the Simplified Diet in clinical practice. The survey identified areas of strong agreement, including introduction of the Simplified Diet at 6 to 12 months of age. The survey also identified areas of widespread variability, including specific Phe or protein thresholds for free/uncounted foods, and whether or not to set daily quantity limits on these foods. Conclusions Significant variability related to implementation of the Simplified Diet exists across U.S.‐based metabolic centers. This practice variability may contribute to differences in the patient experience across centers and may indicate a need for development of clinical guidelines.

From PKU Online Lessons for Dietetics Students to the PKU Sandwiches Album

“…This refers to all fruits and vegetables for which 1 Phe exchanger is greater than 20 g. Contrary to Europe, in dietary treatment in PKU in the US, Phe calculation in whole diet is recommended. Recently, some tendency to use the Simplified Diet, but not to liberalize it has been observed [23]. Not long ago, in the US this trend was not recommended to pregnant women and children under 2 years of age, because no data were published on the degree of metabolic control attained with the Simplified Diet in those groups.…”

“…Not long ago, in the US this trend was not recommended to pregnant women and children under 2 years of age, because no data were published on the degree of metabolic control attained with the Simplified Diet in those groups. In the research by Hansen et al [23], 46% of respondents indicated that the lack of educational materials was barrier to the use of the Simplified Diet. The PKU Sandwiches Album that we offer is the first step to the simplified PKU diet.…”

Protein substitutions as new-generation pharmanutrition approach to managing phenylketonuria

“…Simple carbohydrates and fats are important sources of energy in Phe-restricted diets. 9,10) To ensure patient growth and development, daily protein is provided using Phe-free amino acid mixtures containing essential amino acids in appropriate proportions. 10) The observation of this restrictive diet is difficult for both patients and their parents and requires much planning and coordination.…”

Growth and Nutritional Status of Phenylketonuric Children and Adolescents

“…High phe, if left untreated, can harm the brain and nervous system by disrupting synapses and affecting neurotransmitter metabolism (2). Severe mental retardation, epilepsy, growth retardation, psychological issues, hyperactivity, progressive microcephaly, overall weakness, dermatitis, urine odor of a dead mouse, hypopigmentation, blond hair, and iris blue are all symptoms of this condition (1,(7)(8)(9)(10)(11)(12)(13)(14). The frequency of PKU varies greatly between ethnic groups and geographical areas (15).…”