Omega-3 LC-PUFA supply and neurological outcomes in children with phenylketonuria (PKU)

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).

Complications of the Low Phenylalanine Diet for Patients with Phenylketonuria and the Benefits of Increased Natural Protein

Phenylketonuria (PKU) is an inherited disorder in which phenylalanine (Phe) is not correctly metabolized leading to an abnormally high plasma Phe concentration that causes profound neurologic damage if left untreated. The mainstay of treatment for PKU has centered around limiting natural protein in the diet while supplementing with medical foods in order to prevent neurologic injury while promoting growth. This review discusses several deleterious effects of the low Phe diet along with benefits that have been reported for patients with increased natural protein intake while maintaining plasma Phe levels within treatment guidelines.

IgE-mediated fish allergy in children: is omega-3 supplementation useful?

The management of fish allergy relies on the elimination of all fish from the diet. Nevertheless, an exclusion diet can be problematic from a paediatric nutritional perspective. The issue of a substitute diet for children suffering from fish allergy seems to be not adequately addressed and the consequences of a fish exclusion diet in paediatric age are not known. Fish has an important nutritional value, it is rich in vitamins of group B, D and A, selenium, calcium and phosphorus, iron, zinc, magnesium, iodine and omega-3. While vitamins and iodine are normally present in the diet, omega-3 is present in few other foods, such as vegetable seed oils and nuts. Hence, the scientific research indicates a generic advice regarding a possible omega-3 supplementation in children with fish allergy. Given the knowledge about omega-3 supplementation having a potential good risk-benefit ratio and the absence of serious adverse events related to the omega-3 supplementation, this type of supplementation may seem advisable in children affected by fish allergy.

Uses and Applications of Docosahexaenoic Acid (DHA) in Pediatric Gastroenterology: Current Evidence and New Perspective

In this paper, we will review the dietary allowances of these fatty acids in the paediatric population, and also the indications in different pathologies within the field of pediatric gastroenterology. Finally, we will try to explain the reasons that may justify the difficulty in translating good results in experimental studies to the usual clinical practice. This "good results" may be too little to be detected or there may be other causes but misinterpreted as effects of DHA.

Effects of omega-3 fatty acids supplementation on inflammatory parameters after chronic administration of L-tyrosine

Tyrosinemia type II is an autosomal recessive inborn error of metabolism caused by hepatic cytosolic tyrosine aminotransferase deficiency. Importantly, this disease is associated with neurological and developmental abnormalities in many patients. Considering that the mechanisms underlying neurological dysfunction in hypertyrosinemic patients are poorly understood, in the present work we investigated the levels of cytokines - tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-10 - in cerebellum, hippocampus, striatum of young rats exposed to chronic administration of L-tyrosine. In addition, we also investigated the impact of the supplementation with Omega-3 fatty acids (n-3 PUFA) on the rodent model of Tyrosinemia. Notably, previous study demonstrated an association between L-tyrosine toxicity and n-3 PUFA deficiency. Our results showed a significant increase in the levels of pro- and anti-inflammatory cytokines in brain structures when animals were administered with L-tyrosine. Cerebral cortex and striatum seem to be more susceptible to the inflammation induced by tyrosine toxicity. Importantly, n-3 PUFA supplementation attenuated the alterations on cytokines levels induced by tyrosine exposure in brain regions of infant rats. In conclusion, the brain inflammation is also an important process related to tyrosine neurotoxicity observed in the experimental model of Tyrosinemia. Finally, n-3 PUFA supplementation could be considered as a potential neuroprotective adjunctive therapy for Tyrosinemias, especially type II.

Nutrition and medical support during pregnancy and lactation in women with inborn errors of intermediary metabolism disorders (IEMDs)

The establishment of expanded newborn screening (NBS) not only results in the early diagnosis and treatment of neonates with inborn errors of intermediary metabolism disorders (IEMDs) but also helps the affected females to reach the reproductive age under medical and dietetic support, as well as to give birth to normal infants. In this review, we aimed to focus on laboratory investigation tests, dietetic management and medical support for most known IEMD pregnant and lactating women, such as those suffering from aminoacidopathies, carbohydrate metabolic diseases and fatty acid (FAO) oxidation disorders.

Psychiatric and Cognitive Aspects of Phenylketonuria: The Limitations of Diet and Promise of New Treatments

Phenylketonuria (PKU) is a recessive disorder of phenylalanine metabolism due to mutations in the gene for phenylalanine hydroxylase (PAH). Reduced PAH activity results in significant hyperphenylalaninemia, which leads to alterations in cerebral myelin and protein synthesis, as well as reduced levels of serotonin, dopamine, and noradrenaline in the brain. When untreated, brain development is grossly disrupted and significant intellectual impairment and behavioral disturbance occur. The advent of neonatal heel prick screening has allowed for diagnosis at birth, and the institution of a phenylalanine restricted diet. Dietary treatment, particularly when maintained across neurodevelopment and well into adulthood, has resulted in markedly improved outcomes at a cognitive and psychiatric level for individuals with PKU. However, few individuals can maintain full dietary control lifelong, and even with good control, an elevated risk remains of-in particular-mood, anxiety, and attentional disorders across the lifespan. Increasingly, dietary recommendations focus on maintaining continuous dietary treatment lifelong to optimize psychiatric and cognitive outcomes, although the effect of long-term protein restricted diets on brain function remains unknown. While psychiatric illness is very common in adult PKU populations, very little data exist to guide clinicians on optimal treatment. The advent of new treatments that do not require restrictive dietary management, such as the enzyme therapy Pegvaliase, holds the promise of allowing patients a relatively normal diet alongside optimized mental health and cognitive functioning.

Determinants of Plasma Docosahexaenoic Acid Levels and Their Relationship to Neurological and Cognitive Functions in PKU Patients: A Double Blind Randomized Supplementation Study

Children with phenylketonuria (PKU) follow a protein restricted diet with negligible amounts of docosahexaenoic acid (DHA). Low DHA intakes might explain subtle neurological deficits in PKU. We studied whether a DHA supply modified plasma DHA and neurological and intellectual functioning in PKU. In a double-blind multicentric trial, 109 PKU patients were randomized to DHA doses from 0 to 7 mg/kg&day for six months. Before and after supplementation, we determined plasma fatty acid concentrations, latencies of visually evoked potentials, fine and gross motor behavior, and IQ. Fatty acid desaturase genotypes were also determined. DHA supplementation increased plasma glycerophospholipid DHA proportional to dose by 0.4% DHA per 1 mg intake/kg bodyweight. Functional outcomes were not associated with DHA status before and after intervention and remained unchanged by supplementation. Genotypes were associated with plasma arachidonic acid levels and, if considered together with the levels of the precursor alpha-linolenic acid, also with DHA. Functional outcomes and supplementation effects were not significantly associated with genotype. DHA intakes up to 7 mg/kg did not improve neurological functions in PKU children. Nervous tissues may be less prone to low DHA levels after infancy, or higher doses might be required to impact neurological functions. In situations of minimal dietary DHA, endogenous synthesis of DHA from alpha-linolenic acid could relevantly contribute to DHA status.

Status of nutrients important in brain function in phenylketonuria: a systematic review and meta-analysis

Background

Despite early and ongoing dietary management with a phe-restricted diet, suboptimal neuropsychological function has been observed in PKU. The restrictive nature of the PKU diet may expose patients to sub-optimal nutritional intake and deficiencies which may impact normal brain function. A systematic review of the published literature was carried out, where possible with meta-analysis, to compare the status of nutrients (Nutrients: DHA, EPA phospholipids, selenium, vitamins B₆, B₁₂, E, C, A, D, folic acid, choline, uridine, calcium, magnesium, zinc, iron, iodine and cholesterol) known to be important for brain development and functioning between individuals with PKU and healthy controls.

Results

Of 1534 publications identified, 65 studies met the entry criteria. Significantly lower levels of DHA, EPA and cholesterol were found for PKU patients compared to healthy controls. No significant differences in zinc, vitamins B₁₂, E and D, calcium, iron and magnesium were found between PKU patients and controls. Because of considerable heterogeneity, the meta-analyses findings for folate and selenium were not reported. Due to an insufficient number of publications (< 4) no meta-analysis was undertaken for vitamins A, C and B₆, choline, uridine, iodine and phospholipids.

Conclusions

The current data show that PKU patients have lower availability of DHA, EPA and cholesterol. Compliance with the phe-restricted diet including the micronutrient fortified protein substitute (PS) is essential to ensure adequate micronutrient status. Given the complexity of the diet, patients’ micronutrient and fatty acid status should be continuously monitored, with a particular focus on patients who are non-compliant or poorly compliant with their PS. Given their key role in brain function, assessment of the status of nutrients where limited data was found (e.g. choline, iodine) should be undertaken. Standardised reporting of studies in PKU would strengthen the output of meta-analysis and so better inform best practice for this rare condition.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0839-x) contains supplementary material, which is available to authorized users.

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.

Micronutrients, Essential Fatty Acids and Bone Health in Phenylketonuria

INTRODUCTION

In phenylketonuria (PKU), a natural protein-restricted dietary treatment prevents severe cognitive impairment. Nutrient deficiencies may occur due to strict diet. This study is aimed at evaluating the dietary intake and blood concentrations of micronutrients and essential fatty acids (FA), bone mineral density (BMD) and fracture history in patients on long-term dietary treatment.

METHODS

Sixty early diagnosed Dutch patients (aged 1-39 years) were included in a multi-center cross-sectional study. Their dietary intake, blood concentrations of micronutrients, FA, fracture history and BMD were assessed.

RESULTS

Selenium dietary intake and serum concentrations were low in 14 and 46% of patients, respectively. The serum 25-OH vitamin D2 + D3 concentration was low in 14% of patients while 20% of patients had a low vitamin D intake. Zinc serum concentrations were below normal in 14% of patients, despite adequate intake. Folic acid serum concentrations and intake were elevated. Despite safe total protein and fat intake, arginine plasma concentrations and erythrocyte eicosapentaenoic acid were below reference values in 19 and 6% of patients, respectively. Low BMD (Z-score <-2) was slightly more prevalent in patients, but the lifetime fracture prevalence was comparable to the general population.

CONCLUSIONS

Dutch patients with PKU on long-term dietary treatment have a near normal nutrient status. Supplementation of micronutrients of which deficiency may be deleterious (e.g., vitamin D and selenium) should be considered. BMD warrants further investigation.

Updated, web-based nutrition management guideline for PKU: An evidence and consensus based approach

BACKGROUND

In 2014, recommendations for the nutrition management of phenylalanine hydroxylase deficiency were published as a companion to the concurrently published American College of Medical Genetics and Genomics guideline for the medical treatment of phenylketonuria (PKU). These were developed primarily from a summary of findings from the PKU scientific review conference sponsored by the National Institutes of Health and Agency for Healthcare Research & Quality along with additional systematic literature review. Since that time, the Genetic Metabolic Dietitians International and the Southeast Regional Newborn Screening and Genetics Collaborative have partnered to create a web-based technology platform for the update and development of nutrition management guidelines for inherited metabolic disorders.

OBJECTIVE

The purpose of this PKU guideline is to establish harmonization in treatment and monitoring, to guide the integration of nutrition therapy in the medical management of PKU, and to improve outcomes (nutritional, cognitive, and developmental) for individuals with PKU in all life stages while reducing associated medical, educational, and social costs.

METHODS

Six research questions critical to PKU nutrition management were formulated to support guideline development: Review, critical appraisal, and abstraction of peer-reviewed studies and unpublished practice literature, along with expert Delphi survey feedback, nominal group process, and external review from metabolic physicians and dietitians were utilized for development of recommendations relevant to each question. Recommendations address nutrient intake, including updated protein requirements, optimal blood phenylalanine concentrations, nutrition interventions, monitoring parameters specific to life stages, adjunct therapies, and pregnancy and lactation. Recommendations were graded using a rigorous system derived from the Academy of Nutrition and Dietetics.

RESULTS AND CONCLUSION

These guidelines, updated utilizing a thorough and systematic approach to literature analysis and national consensus process, are now easily accessible to the global community via the newly developed digital platform. For additional details on specific topics, readers are encouraged to review materials on the online portal: https://GMDI.org/.

Long-chain polyunsaturated fatty acid status in children, adolescents and adults with phenylketonuria

BACKGROUND

Patients with phenylketonuria have been reported to be deficient in long-chain polyunsaturated fatty acids (LCPUFAs). It has been postulated that good compliance with the dietary regimen negatively influences LCPUFA status.

METHODS

In 36 patients with phenylketonuria and 18 age-matched healthy control subjects LCPUFA-levels in plasma phospholipids and cholesteryl esters, erythrocyte phosphatidylcholine and phosphatidylethanolamine were evaluated.

RESULTS

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels did not differ significantly between patients and control subjects in plasma and erythrocyte fractions. There was a significant negative correlation between SDS (standard deviation) scores of DHA-levels in erythrocyte parameters from the respective age-matched control group and patients' concurrent and long-term phenylalanine levels for erythrocyte phosphatidylethanolamine and erythrocyte phosphatidylcholine. Patients with lower (higher) phenylalanine levels had positive (negative) DHA-SDS.

CONCLUSION

In contrast to previous reports we did not find lower LCPUFA-levels in patients with phenylketonuria compared to age-matched healthy control subjects. Good dietary control was associated with better LCPUFA status.

A Specific Nutrient Combination Attenuates the Reduced Expression of PSD-95 in the Proximal Dendrites of Hippocampal Cell Body Layers in a Mouse Model of Phenylketonuria

The inherited metabolic disease phenylketonuria (PKU) is characterized by increased concentrations of phenylalanine in the blood and brain, and as a consequence neurotransmitter metabolism, white matter, and synapse functioning are affected. A specific nutrient combination (SNC) has been shown to improve synapse formation, morphology and function. This could become an interesting new nutritional approach for PKU. To assess whether treatment with SNC can affect synapses, we treated PKU mice with SNC or an isocaloric control diet and wild-type (WT) mice with an isocaloric control for 12 weeks, starting at postnatal day 31. Immunostaining for post-synaptic density protein 95 (PSD-95), a post-synaptic density marker, was carried out in the hippocampus, striatum and prefrontal cortex. Compared to WT mice on normal chow without SNC, PKU mice on the isocaloric control showed a significant reduction in PSD-95 expression in the hippocampus, specifically in the granular cell layer of the dentate gyrus, with a similar trend seen in the cornus ammonis 1 (CA1) and cornus ammonis 3 (CA3) pyramidal cell layer. No differences were found in the striatum or prefrontal cortex. PKU mice on a diet supplemented with SNC showed improved expression of PSD-95 in the hippocampus. This study gives the first indication that SNC supplementation has a positive effect on hippocampal synaptic deficits in PKU mice.

An Opinion on "Staging" of Infant Formula: A Developmental Perspective on Infant Feeding

Breast milk is a dynamic fluid with compositional changes occurring throughout the period of lactation. Some of these changes in nutrient concentrations reflect the successively slowing growth rate and developmental changes in metabolic requirements that infants undergo during the first year of life. Infant formula, in contrast, has a static composition, intended to meet the nutritional requirements of infants from birth to 6 or 12 months of age. To better fit the metabolic needs of infants and to avoid nutrient limitations or excesses, we suggest that infant formulas should change in composition with the age of the infant, that is, different formulas are created/used for different ages during the first year of life. We propose that specific formulas for 0 to 3 months (stage 1), 3 to 6 months (stage 2), and 6 to 12 months (stage 3) of age may be nutritionally and physiologically advantageous to infants. Although this initially may impose some difficult practical/conceptual issues, we believe that this staging concept would improve nutrition of formula-fed infants and, ultimately, improve outcomes and make their performance more similar to that of breast-fed infants.

Antioxidant treatment strategies for hyperphenylalaninemia

Hyperphenylalaninemia (HPA) leads to increased oxidative stress in patients with phenylketonuria (PKU) and in animal models of PKU. Early diagnosis and immediate adherence to a phenylalanine-restricted diet prevents HPA and, consequently, severe brain damage. However, treated adolescent and adult PKU patients have difficulties complying with the diet, leading to an oscillation of phenylalanine levels and associated oxidative stress. The brain is especially susceptible to reactive species, and oxidative stress might add to the impaired cognitive function found in these patients. The restricted PKU diet has a very limited nutrient content from natural foods and almost no animal protein, which reduces the intake of important compounds. These specific compounds can act as scavengers of reactive species and can be co-factors of antioxidant enzymes. Supplementation with nutrients, vitamins, and tetrahydropterin has given quite promising results in patients and animal models. Antioxidant supplementation has been studied in HPA, however there is no consensus about its always beneficial effects. In this way, regular exercise could be a beneficial addition on antioxidant status in PKU patients. A deeper understanding of PKU molecular biochemistry, and genetics, as well as the need for improved targeted treatment options, could lead to the development of new therapeutic strategies.

Evaluation of plasma trace element and mineral status in children and adolescents with phenylketonuria using data from inductively-coupled-plasma atomic emission and mass spectrometric analysis

BACKGROUND

Phenylketonuria (PKU) is caused by a severe phenylalanine hydroxylase deficiency; the mainstay of treatment is a low-phenylalanine diet. A diet which is so restrictive is associated with a risk of nutritional deficiencies. We investigated plasma concentrations for 46 elements, including minerals and trace elements.

METHODS

We enrolled 20 children and adolescents with PKU and 20 matched controls. Multi-elementary quantification was carried out by solution-based inductively coupled plasma atomic emission spectroscopy (ICP-AES) and ICP mass spectrometry (ICP-MS).

RESULTS

With the exception of manganese and aluminium, no significant differences were found for element levels between PKU patients and controls. As a trend, manganese levels were lower in PKU patients than in control subjects (p < 0.05) but were within the reference range. There was a positive linear relationship between manganese and tyrosine levels in subjects with PKU (r(2) = 0.2295, p < 0.05). If detectable, potentially toxic elements were only identified in ultra-trace quantities in plasma samples of either group; aluminium levels were found to be slightly higher in PKU subjects than in controls (p < 0.01).

CONCLUSION

The combination of ICP-AES and ICP-MS data is a useful diagnostic tool for element quantification at a high analytical rate and for monitoring bio-element status, e.g. in patients on a restrictive diet.

Omega 3 fatty acids and inborn errors of metabolism

A number of studies are investigating the role of n-3 polyunsaturated fatty acids in children with metabolic inborn errors, while the effects on visual and brain development in premature infants and neonates are well known. However, their function incertain chronic neurological, inflammatory and metabolic disorders is still under study. Standards should be established to help identify the need of docosahexaenoic acid supplementation in conditions requiring a restricted diet resulting in an altered metabolism system, and find scientific evidence on the effects of such supplementation. This study reviews relevant published literature to propose adequate n-3 intake or supplementation doses for different ages and pathologies. The aim of this review is to examine the effects of long chain polyunsaturated fatty acids supplementation in preventing cognitive impairment or in retarding its progress, and to identify nutritional deficiencies, in children with inborn errors of metabolism. Trials were identified from a search of the Cochrane and MEDLINE databases in 2011. These databases include all major completed and ongoing double-blind, placebo-controlled, randomized trials, as well as all studies in which omega-3 supplementation was administered to children with inborn errors, and studies assessing omega-3 fatty acids status in plasma in these pathologies. Although few randomized controlled trials met the inclusion criteria of this review, some evidenced that most of children with inborn errors are deficient in omega-3 fatty acids, and demonstrated that supplementation might improve their neural function, or prevent the progression of neurological impairment. Nontheless, further investigations are needed on this issue.

Phenylketonuria: nutritional advances and challenges

Despite the appearance of new treatment, dietary approach remains the mainstay of PKU therapy. The nutritional management has become complex to optimize PKU patients' growth, development and diet compliance. This paper review critically new advances and challenges that have recently focused attention on potential relevant of LCPUFA supplementation, progress in protein substitutes and new protein sources, large neutral amino acids and sapropterin. Given the functional effects, DHA is conditionally essential substrates that should be supplied with PKU diet in infancy but even beyond. An European Commission Programme is going on to establish quantitative DHA requirements in this population. Improvements in the palatability, presentation, convenience and nutritional composition of protein substitutes have helped to improve long-term compliance with PKU diet, although it can be expected for further improvement in this area. Glycomacropeptide, a new protein source, may help to support dietary compliance of PKU subject but further studies are needed to evaluate this metabolic and nutritional issues. The PKU diet is difficult to maintain in adolescence and adult life. Treatment with large neutral amino acids or sapropterin in selected cases can be helpful. However, more studies are necessary to investigate the potential role, dose, and composition of large neutral amino acids in PKU treatment and to show long-term efficacy and tolerance. Ideally treatment with sapropterin would lead to acceptable blood Phe control without dietary treatment but this is uncommon and sapropterin will usually be given in combination with dietary treatment, but clinical protocol evaluating adjustment of PKU diet and sapropterin dosage are needed.

In conclusion PKU diet and the new existing treatments, that need to be optimized, may be a complete and combined strategy possibly positive impacting on the psychological, social, and neurocognitive life of PKU patients.

Follow up of phenylketonuria patients

In recent years our understanding of the follow up policies for PKU has increased substantially. In particular, we now understand the importance of maintaining control of blood phenylalanine (phe) concentrations life-long to achieve the best long-term neuropsychological outcomes. The concordance with the follow up strategy remains a key challenge for the future, especially with respect to adolescents and young adults. The recent therapies could ease the burden of the dietary phe restriction for PKU patients and their families. The time may be right for revisiting the guidelines for follow up of PKU in order to address a number of important issues related to PKU management: promotion of breastfeeding to complementary feeding up to 2 years of age for prevention of early growth retardation and later overweight development, treatment advancements for metabolic control, blood phe and tyr variability, routine screening measures for nutritional biomarkers, neurocognitive and psychological assessments, bone pathology, understanding the challenges of compliance and transitioning into adulthood as an individual with PKU and addressing unmet needs in this population.

Fatty acid profile in patients with phenylketonuria and its relationship with bone mineral density

BACKGROUND

Patients with phenylketonuria (PKU) undergo a restrictive vegan-like diet, with almost total absence of n-3 fatty acids, which have been proposed as potential contributors to bone formation in the healthy population. The PKU diet might lead these patients to bone mass loss and, consequently, to the development of osteopenia/osteoporosis. Therefore, we proposed to analyze their plasma fatty acid profile status and its relationship with bone health.

METHODS

We recruited 47 PKU patients for this cross-sectional study and divided the cohort into three age groups (6-10 years, 11-18 years, 19-42 years). We measured their plasma fatty acid profile and bone mineral density (BMD) (both at the femoral neck and the lumbar spine). Seventy-seven healthy controls also participated as reference values of plasma fatty acids.

RESULTS

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and total n-3 fatty acids were significantly diminished in PKU patients compared with healthy controls. DHA, EPA, and total n-3 fatty acids were also positively associated with bone mineral density (r = 0.83, p = 0.010; r = 0.57, p = 0.006; r = 0.73, p = 0.040, respectively). There was no association between phenylalanine (Phe), Index of Dietary Control (IDC), calcium, 25-hydroxivitamin D concentrations, daily calcium intake, and BMD.

CONCLUSION

Our results suggest a possible influence of essential fatty acids over BMD in PKU patients. The lack of essential n-3 fatty acids intake in the PKU diet might affect bone mineralization. Further clinical trials are needed to confirm the effect of the n-3 essential fatty acids on bone accrual in a cohort of PKU patients.

Suboptimal outcomes in patients with PKU treated early with diet alone: revisiting the evidence

BACKGROUND

The National Institute of Health (NIH) published a Consensus Statement on the screening and management of Phenylketonuria (PKU) in 2000. The panel involved in the development of this consensus statement acknowledged the lack of data regarding the potential for more subtle suboptimal outcomes and the need for further research into treatment options. In subsequent years, the approval of new treatment options for PKU and outcome data for patients treated from the newborn period by dietary therapy alone have become available. We hypothesized that a review of the PKU literature since 2000 would provide further evidence related to neurocognitive, psychosocial, and physical outcomes that could serve as a basis for reassessment of the 2000 NIH Consensus Statement.

METHODS

A systematic review of literature residing in PubMed, Scopus and PsychInfo was performed in order to assess the outcome data over the last decade in diet-alone early-treated PKU patients to assess the need for new recommendations and validity of older recommendations in light of new evidence.

RESULTS

The majority of publications (140/150) that contained primary outcome data presented at least one suboptimal outcome compared to control groups or standardized norms/reference values in at least one of the following areas: neurocognitive/psychosocial (N=60; 58 reporting suboptimal outcomes); quality of life (N=6; 4 reporting suboptimal outcomes); brain pathology (N=32; 30 reporting suboptimal outcomes); growth/nutrition (N=34; 29 reporting suboptimal outcomes); bone pathology (N=9; 9 reporting suboptimal outcomes); and/or maternal PKU (N=19; 19 reporting suboptimal outcomes).

CONCLUSIONS

Despite the remarkable success of public health programs that have instituted newborn screening and early introduction of dietary therapy for PKU, there is a growing body of evidence that suggests that neurocognitive, psychosocial, quality of life, growth, nutrition, bone pathology and maternal PKU outcomes are suboptimal. The time may be right for revisiting the 2000 NIH Consensus Statement in order to address a number of important issues related to PKU management, including treatment advancements for metabolic control in PKU, blood Phe variability, neurocognitive and psychological assessments, routine screening measures for nutritional biomarkers, and bone pathology.

Supplementation of polyunsaturated fatty acids, magnesium and zinc in children seeking medical advice for attention-deficit/hyperactivity problems - an observational cohort study

BACKGROUND

Polyunsaturated fatty acids are essential nutrients for humans. They are structural and functional components of cell membranes and pre-stages of the hormonally and immunologically active eicosanoids. Recent discoveries have shown that the long-chained omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) also play an important role in the central nervous system. They are essential for normal brain functioning including attention and other neuropsychological skills.

MATERIALS AND METHODS

In our large observational study we monitored 810 children from 5 to 12 years of age referred for medical help and recommended for consuming polyunsaturated fatty acids (PUFA) in combination with zinc and magnesium by a physician over a period of at least 3 months. The food supplement ESPRICO® (further on referred to as the food supplement) is developed on the basis of current nutritional science and containing a combination of omega-3 and omega-6 fatty acids as well as magnesium and zinc. Study objective was to evaluate the nutritional effects of the PUFA-zinc-magnesium combination on symptoms of attention deficit, impulsivity, and hyperactivity as well as on emotional problems and sleep related parameters. Assessment was performed by internationally standardised evaluation scales, i.e. SNAP-IV and SDQ. Tolerance (adverse events) and acceptance (compliance) of the dietary therapy were documented.

RESULTS

After 12 weeks of consumption of a combination of omega-3 and omega-6 fatty acids as well as magnesium and zinc most subjects showed a considerable reduction in symptoms of attention deficit and hyperactivity/impulsivity assessed by SNAP-IV. Further, the assessment by SDQ revealed fewer emotional problems at the end of the study period compared to baseline and also sleeping disorders. Mainly problems to fall asleep, decreased during the 12 week nutritional therapy. Regarding safety, no serious adverse events occurred. A total of 16 adverse events with a possible causal relationship to the study medication were reported by 14 children (1.7%) and only 5.2% of the children discontinued the study due to acceptance problems. Continuation of consumption of the food supplement was recommended by the paediatricians for 61.1% of the children.

CONCLUSION

Our results suggest a beneficial effect of a combination of omega-3 and omega-6 fatty acids as well as magnesium and zinc consumption on attentional, behavioural, and emotional problems of children and adolescents. Thus, considering the behavioural benefit in combination with the low risk due to a good safety profile, the dietary supplementation with PUFA in combination with zinc and magnesium can be recommended.

Effects of long-chain polyunsaturated fatty acid supplementation on neurodevelopment in childhood: a review of human studies

Omega-3 and omega-6 long-chain polyunsaturated fatty acids (LCPUFA) are critical for infant and childhood brain development, but levels of the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are often low in the Western diet. Increasing evidence from both epidemiological and intervention studies, reviewed here, indicates that DHA supplementation, during pregnancy, lactation, or childhood plays an important role in childhood neurodevelopment. Arachidonic acid (ARA) is also important for infant growth and development. Several studies have demonstrated positive associations between blood DHA levels and improvements on tests of cognitive and visual function in healthy children. Controlled trials also have shown that supplementation with DHA and EPA may help in the management of childhood psychiatric disorders, and improve visual and motor functions in children with phenylketonuria. In all studies, DHA and EPA supplementation is typically well tolerated. Further research is needed to determine optimal doses for efficacy at different developmental ages. The potential long-term benefits of early LCPUFA supplementation also require consideration.