Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis

The traditional treatment for phenylketonuria (PKU) is a phenylalanine (Phe)-restricted diet, supplemented with a Phe-free/low-Phe protein substitute. Pharmaceutical treatment with synthetic tetrahydrobiopterin (BH4), an enzyme cofactor, allows a patient subgroup to relax their diet. However, dietary protocols guiding the adjustments of protein equivalent intake from protein substitute with BH4 treatment are lacking. We systematically reviewed protein substitute usage with long-term BH4 therapy. Electronic databases were searched for articles published between January 2000 and March 2020. Eighteen studies (306 PKU patients) were eligible. Meta-analyses demonstrated a significant increase in Phe and natural protein intakes and a significant decrease in protein equivalent intake from protein substitute with cofactor therapy. Protein substitute could be discontinued in 51% of responsive patients, but was still required in 49%, despite improvement in Phe tolerance. Normal growth was maintained, but micronutrient deficiency was observed with BH4 treatment. A systematic protocol to increase natural protein intake while reducing protein substitute dose should be followed to ensure protein and micronutrient requirements are met and sustained. We propose recommendations to guide healthcare professionals when adjusting dietary prescriptions of PKU patients on BH4. Studies investigating new therapeutic options in PKU should systematically collect data on protein substitute and natural protein intakes, as well as other nutritional factors

Long-Term Growth in Phenylketonuria: A Systematic Review and Meta-Analysis

There is an ongoing debate regarding the impact of phenylketonuria (PKU) and its treatment on growth. To date, evidence from studies is inconsistent, and data on the whole developmental period is limited. The primary aim of this systematic review was to investigate the effects of a phenylalanine (Phe)-restricted diet on long-term growth in patients with PKU. Four electronic databases were searched for articles published until September 2018. A total of 887 results were found, but only 13 articles met eligibility criteria. Only three studies had an adequate methodology for meta-analysis. Although the results indicate normal growth at birth and during infancy, children with PKU were significantly shorter and had lower weight for age than reference populations during the first four years of life. Impaired linear growth was observed until the end of adolescence in PKU. In contrast, growth impairment was not reported in patients with mild hyperphenylalaninemia, not requiring dietary restriction. Current evidence indicates that even with advances in dietary treatments, "optimal" growth outcomes are not attained in PKU. The majority of studies include children born before 1990s, so further research is needed to show the effects of recent dietary practices on growth in PKU.info:eu-repo/semantics/publishedVersio

Development of a practical dietitian road map for the nutritional management of phenylketonuria (PKU) patients on pegvaliase

Funding Information: Outside the submitted work, the authors disclose the following. Bausell H received personal fees from BioMarin, Ultragenyx, Horizon and Vitaflo. Bélanger-Quintana A reports personal fees from BioMarin, Nutricia, Vitaflo, Orphan Europe, Takeda and Genzyme. Rocha JC received research grants from BioMarin, Glutamine and Cambrooke, as well as personal fees from BioMarin, Applied Pharma Research, Nutricia, Merck Serono, Vitaflo, Cambrooke, PIAM and Lifediet. MacDonald A reports research funding from BioMarin, Nutricia, Applied Pharma Research, Vitaflo, Galen, Metax, Mevalia and Arla, as well as lecture fees from BioMarin, Applied Pharma Research, Nutricia and Vitaflo, and consultancy fees from BioMarin, Applied Pharma Research, Arla, Nutricia and Vitaflo. Met Ed reports grant funding from BioMarin, Nutricia, Vitaflo and Horizon Pharmaceuticals. Bernstein L and Rohr F report lecture fees from Vitaflo. Publisher Copyright: © 2021 The Authors Copyright: Copyright 2021 Elsevier B.V., All rights reserved.Background: The metabolic dietitian/nutritionist (hereafter ‘dietitian’) plays an essential role in the nutritional management of patients with phenylketonuria (PKU), including those on pegvaliase. Currently, more educational support and clinical experience is needed to ensure that dietitians are prepared to provide optimal nutritional management and counselling of pegvaliase-treated patients. Methods: Via a face-to-face data-review meeting, followed by a virtual consolidation meeting, a group of expert dietitians and one paediatrician discussed and developed a series of recommendations on the nutritional evaluation and management of patients receiving pegvaliase. The consensus group consisted of 10 PKU experts: six dietitians and one paediatrician from Europe and three dietitians from the US. One European and three US dietitians had experience with pegvaliase-treated patients. Results: The consensus group recommended that a physician, dietitian and nurse are part of the pegvaliase treatment team. Additionally, a psychologist/counsellor should be included if available. Practical proposals for the nutritional evaluation of pegvaliase-treated patients at baseline, during the induction and titration phases and for long-term maintenance were developed. The consensus group suggested assessment of blood Phe at least monthly or every 2 weeks in the event of low blood Phe (i.e., blood Phe <30 μmol/L). It may be appropriate to increase blood Phe monitoring when adjusting protein intake and/or pegvaliase dose. It was recommended that natural protein intake is increased by 10–20 g increments if blood Phe concentrations decrease to <240 μmol/L in patients who are not meeting the dietary reference intake for natural protein of 0.8 g/kg. It was proposed that with pegvaliase treatment blood Phe levels could be maintained <240 μmol/L but more evidence on the safety of achieving physiological blood Phe levels is necessary before any recommendation on the lower blood Phe target can be given. Finally, both patients and dietitians should have access to educational resources to optimally support patients receiving pegvaliase. Conclusion: This practical road map aims to provide initial recommendations for dietitians monitoring patients with PKU prescribed pegvaliase. Given that practical experience with pegvaliase is still limited, nutritional recommendations will require regular updating once more evidence is available and clinical experience evolves.publishersversionpublishe

A New Concept in the Nutrition Therapy of Childhood Obesity: Food Insulin Index

Healthy lifestyle changes including promoting healthy eating habits and increasing the level of physical activity are the first steps in the treatment of childhood obesity. However, failure to achieve the desired success with traditional approaches has led clinicians to seek new treatments. One of the most interesting approaches has been diets based on the regulation of postprandial blood glucose and insulin levels. With these diets, the concept of glycemic index (GI), which is used to evaluate the glycemic response of carbohydrate-containing foods, has come to the fore. In the studies conducted, it is suggested that low GI diets may help in the treatment of obesity by showing the relationship between GI of diets and obesity, and obtaining results that could reduce food intake and hunger feelings as well as postprandial blood glucose and insulin levels by low GI meals. On the other hand, it is confusing to know that not only carbohydrates, but also proteins and fats have a role on postprandial insulin release. Therefore, considering the GI to control postprandial glycemic and insulinemic response is inadequate, and a method of assessing the effects of proteins and fats as well as carbohydrates is needed. In order to meet this requirement, the concept of food insulin index (FII) has been developed. The positive results on postprandial insulin response and appetite are promising, while the number of studies on FII, a relatively new concept, is limited. As a result, the use of low GI and FIT diets may be beneficial in the treatment of childhood obesity. Nevertheless, there is a need for more well-planned short- and long-term studies in order to make definitive recommendations