A questionnaire survey on the usage of low protein staple foods by people with phenylketonuria in Scotland

A food pyramid for adult patients with phenylketonuria and a systematic review on the current evidences regarding the optimal dietary treatment of adult patients with PKU

Early dietary treatment is mind-saving in patients with phenylketonuria. A "diet-for-life" is advocated, aimed to prevent effects of chronic exposure to hyperphenylalaninemia. While adherence to diet is significant during childhood as patients are followed-up at specialized metabolic centers, during adolescence and adulthood percentage of patients discontinuing diet and/or lost at follow-up is still high. The process of passing skills and responsibilities from pediatric team to adult team is defined "transition". The goal of transition clinics is to set up specific multidisciplinary care pathways and guarantee continuity of care and compliance of patients to care. In 2017, "The complete European guidelines on phenylketonuria" were published. These guidelines, however, do not provide an easy way to illustrate to adult patients how to follow correct dietary approach. The purpose of this review is to evaluate current evidence on optimum dietary treatment of adults with phenylketonuria and to provide food pyramid for this population. The pyramid built shows that carbohydrates should be consumed every day (3 portions), together with fruits and vegetables (5 portions), extra virgin olive oil, and calcium water (almost 1 L/day); weekly portions can include 150 g potatoes walnuts and hazelnuts (20 g). At top of pyramid, there are two pennants. The green means that, based on individual metabolic phenotype and daily phenylalanine tolerance, patients need personalized supplementation (specific phenylalanine free amino acid mixtures, vitamins and omega 3 fatty acids); the one red indicates foods that are banned from diet (aspartame and protein foods exceeding individual dietary phenylalanine tolerance).

Exploring the Barriers and Motivators to Dietary Adherence among Caregivers of Children with Disorders of Amino Acid Metabolism (AAMDs): A Qualitative Study

Dietary intervention is generally accepted as the mainstay of treatment for patients with disorders of amino acid metabolism (AAMDs). However, dietary adherence to a low-protein diet is always reported as a common challenge among these patients. This study explored the perception of barriers and motivators to dietary adherence among caregivers of AAMD patients in Malaysia. Twenty caregivers of children with AAMDs receiving ongoing treatment at the genetic clinic participated in an online focus group discussion from November to December 2021. Findings showed a total of five interrelated main themes identified from focus group discussion (FGD) exploring parents’ experiences related to the management of their child’s daily diet. The barriers to dietary adherence were burden of dietary treatment, diet and dietary behavior, parenting challenges, limited knowledge related to dietary treatment, and challenges in healthcare system delivery. Key factors facilitating good dietary adherence include good knowledge of dietary treatment, parental coping strategies, social coping, and dietary behavior. In conclusion, despite the existence of several barriers to the implementation of dietary treatment, caregivers managed to use a wide range of coping strategies to overcome some, if not all, of the challenges. The important next step is to develop, in conjunction with multidisciplinary healthcare professionals, feasible implementation strategies that could address these barriers and at the same time improve the quality of life of caregivers.

Special Low Protein Foods Prescribed in England for PKU Patients: An Analysis of Prescribing Patterns and Cost

Patients with phenylketonuria (PKU) are reliant on special low protein foods (SLPFs) as part of their dietary treatment. In England, several issues regarding the accessibility of SLPFs through the national prescribing system have been highlighted. Therefore, prescribing patterns and expenditure on all SLPFs available on prescription in England (n = 142) were examined. Their costs in comparison to regular protein-containing (n = 182) and ‘free-from’ products (n = 135) were also analysed. Similar foods were grouped into subgroups (n = 40). The number of units and costs of SLPFs prescribed in total and per subgroup from January to December 2020 were calculated using National Health Service (NHS) Business Service Authority (NHSBSA) ePACT2 (electronic Prescribing Analysis and Cost Tool) for England. Monthly patient SLPF units prescribed were calculated using patient numbers with PKU and non-PKU inherited metabolic disorders (IMD) consuming SLPFs. This was compared to the National Society for PKU (NSPKU) prescribing guidance. Ninety-eight percent of SLPF subgroups (n = 39/40) were more expensive than regular and ‘free-from’ food subgroups. However, costs to prescribe SLPFs are significantly less than theoretical calculations. From January to December 2020, 208,932 units of SLPFs were prescribed (excluding milk replacers), costing the NHS £2,151,973 (including milk replacers). This equates to £962 per patient annually, and prescribed amounts are well below the upper limits suggested by the NSPKU, indicating under prescribing of SLPFs. It is recommended that a simpler and improved system should be implemented. Ideally, specialist metabolic dietitians should have responsibility for prescribing SLPFs. This would ensure that patients with PKU have the necessary access to their essential dietary treatment, which, in turn, should help promote dietary adherence and improve metabolic control.

Current Practices and Challenges in the Diagnosis and Management of PKU in Latin America: A Multicenter Survey

This study aimed to describe the current practices in the diagnosis and dietary management of phenylketonuria (PKU) in Latin America, as well as the main barriers to treatment. We developed a 44-item online survey aimed at health professionals. After a pilot test, the final version was sent to 25 practitioners working with inborn errors of metabolism (IEM) in 14 countries. Our results include 22 centers in 13 countries. Most countries (12/13) screened newborns for PKU. Phenylalanine (Phe) targets at different ages were very heterogeneous among centers, with greater consistency at the 0-1 year age group (14/22 sought 120-240 µmol/L) and the lowest at >12 years (10 targets reported). Most countries had only unflavored powdered amino acid substitutes (10/13) and did not have low-protein foods (8/13). Only 3/13 countries had regional databases of the Phe content of foods, and only 4/22 centers had nutrient analysis software. The perceived obstacles to treatment were: low purchasing power (62%), limited/insufficient availability of low-protein foods (60%), poor adherence, and lack of technical resources to manage the diet (50% each). We observed a heterogeneous scenario in the dietary management of PKU, and most countries experienced a lack of dietary resources for both patients and health professionals.

A 3 Year Longitudinal Prospective Review Examining the Dietary Profile and Contribution Made by Special Low Protein Foods to Energy and Macronutrient Intake in Children with Phenylketonuria

The nutritional composition of special low protein foods (SLPFs) is controlled under EU legislation for 'Foods for Special Medical Purposes (FSMP)'. They are designed to meet the energy needs of patients unable to eat a normal protein containing diet. In phenylketonuria (PKU), the macronutrient contribution of SLPFs has been inadequately examined.

AIM

A 3-year longitudinal prospective study investigating the contribution of SLPFs to the macronutrient intake of children with early treated PKU.

METHODS

48 children (27 boys) with a mean recruitment age of 9.3 y were studied. Semi-quantitative dietary assessments and food frequency questionnaires (FFQ) were collected three to four times/year for 3 years.

RESULTS

The mean energy intake provided by SLPFs was 33% (SD ± 8), and this figure was 42% (SD ± 13) for normal food and 21% (SD ± 5) for protein substitutes (PS). SLPFs supplied a mean intake of 40% carbohydrate (SD ± 10), 51% starch (SD ± 18), 21% sugar (SD ± 8), and 38% fat (SD ± 13). Fibre intake met 83% of the Scientific Advisory Committee on Nutrition (SACN) reference value, with 50% coming from SLPFs with added gums and hydrocolloids. Low protein bread, pasta and milk provided the highest energy contribution, and the intake of sweet SLPFs (e.g., biscuits, cakes, and chocolate) was minimal. Children averaged three portions fruit/vegetable daily, and children aged ≥ 12 y had irregular meal patterns.

CONCLUSION

SLPFs provide essential energy in phenylalanine restricted diets. Optimising the nutritional quality of SLPFs deserves more attention.

Special Low Protein Foods in the UK: An Examination of Their Macronutrient Composition in Comparison to Regular Foods

Special low protein foods (SLPFs) are essential in a low phenylalanine diet for treating phenylketonuria (PKU). With little known about their nutritional composition, all SLPFs on UK prescription were studied (n = 146) and compared to equivalent protein-containing foods (n = 190). SLPF nutritional analysis was obtained from suppliers/manufacturers. Comparable information about regular protein-containing foods was obtained from online UK supermarkets. Similar foods were grouped together, with mean nutritional values calculated for each subgroup (n = 40) and percentage differences determined between SLPFs and regular food subgroups. All SLPF subgroups contained 43-100% less protein than regular foods. Sixty-three percent (n = 25/40) of SLPF subgroups contained less total fat with palm oil (25%, n = 36/146) and hydrogenated vegetable oil (23%, n = 33/146) key fat sources. Sixty-eight percent (n = 27/40) of SLPF subgroups contained more carbohydrate, with 72% (n = 105/146) containing added sugar. Key SLPF starch sources were maize/corn (72%; n = 105/146). Seventy-seven percent (n = 113/146) of SLPFs versus 18% (n = 34/190) of regular foods contained added fibre, predominantly hydrocolloids. Nine percent of SLPFs contained phenylalanine > 25 mg/100 g and sources of phenylalanine/protein in their ingredient lists. Stricter nutritional composition regulations for SLPFs are required, identifying maximum upper limits for macronutrients and phenylalanine, and fat and carbohydrate sources that are associated with healthy outcomes.

Prescribing issues experienced by people living with phenylketonuria in the UK

Background

Foods for Special Medical purposes (Phe-free protein substitutes [PS] and low protein foods [LPFs]) are central to successful dietary management of patients with phenylketonuria (PKU). In the UK, PS and LPFs are prescribed by primary care general practitioners (GPs) and dispensed by high street pharmacists or via home delivery companies. As patients and carers commonly reported access issues with PS and LPFs through the National Society for PKU (NSPKU) helpline, the NSPKU collected more information about the extent of prescriptions issues via a questionnaire.

Methods

A cross sectional online survey was carried out consisting of 7 multiple choice and 3 open questions. The questionnaire was available via the NSPKU website over a 9-month period (15th May 2018–31st January 2019). Carers or patients with PKU were invited to participate if they had any problems accessing PS and LPF.

Results

There were 252 responses. 65% for children and 35% for adults, aged ≥18y with PKU. 59% (n = 146/246) of responses described difficulties accessing basic LPF (bread, pasta) and 33% (n = 81/248) PS. 36% (n = 88/248) said problems had re-occurred >1y, and 40% (n = 99/248) for <3 months. 59% (n = 146/246) had supply issues with LPF and 33% (n = 81/246) with PS. 18% (n = 42/234) reported that the local NHS authority had refused, restricted or had a policy to block treatment access; 27% (n = 63/234) cited GPs declining requests or restricting prescription amounts. 21% (n = 49/234) could not access all their products via a pharmacy, 40% (n = 93/234) said their home delivery system failed, and 15% (n = 34/234) of the dispensed prescribed products were out of date, incorrect, damaged or poor quality. For patients and carers these issues caused: stress (87%, n = 210/241); they considered PKU was not taken seriously by professionals (66%, n = 160/241); they reduced patient access to LPF and PS (53%, n = 128/241); and affected the patients' health (53%, n = 128/241).

Discussion

Access to PKU dietary treatment is frequently disrupted for reasons relating to GP prescriptions and unreliable dispensing and delivery practices. These issues require immediate attention by UK health professionals in order to create a fairer and more efficient system for everyone.

The complete European guidelines on phenylketonuria: diagnosis and treatment

Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. If left untreated, PKU results in increased phenylalanine concentrations in blood and brain, which cause severe intellectual disability, epilepsy and behavioural problems. PKU management differs widely across Europe and therefore these guidelines have been developed aiming to optimize and standardize PKU care. Professionals from 10 different European countries developed the guidelines according to the AGREE (Appraisal of Guidelines for Research and Evaluation) method. Literature search, critical appraisal and evidence grading were conducted according to the SIGN (Scottish Intercollegiate Guidelines Network) method. The Delphi-method was used when there was no or little evidence available. External consultants reviewed the guidelines. Using these methods 70 statements were formulated based on the highest quality evidence available. The level of evidence of most recommendations is C or D. Although study designs and patient numbers are sub-optimal, many statements are convincing, important and relevant. In addition, knowledge gaps are identified which require further research in order to direct better care for the future.