In infants with phenylketonuria (PKU), dietary management is based on lowering and titrating phenylalanine (Phe) intake from breast milk or standard infant formula in combination with a Phe-free infant formula in order to maintain blood Phe levels within target range. Professionals use different methods to feed infants with PKU and our survey aimed to document practices across Europe. We sent a cross sectional, survey monkey® questionnaire to European health professionals working in IMD. It contained 31 open and multiple-choice questions. The results were analysed according to different geographical regions. Ninety-five centres from 21 countries responded. Over 60% of centres commenced diet in infants by age 10 days, with 58% of centres implementing newborn screening by day 3 post birth. At diagnosis, infant hospital admission occurred in 61% of metabolic centres, mainly in Eastern, Western and Southern Europe. Breastfeeding fell sharply following diagnosis with only 30% of women still breast feeding at 6 months.53% of centres gave pre-measured Phe-free infant formula before each breast feed and 23% alternated breast feeds with Phe-free infant formula. With standard infant formula feeds, measured amounts were followed by Phe-free infant formula to satiety in 37% of centres (n = 35/95), whereas 44% (n = 42/95) advised mixing both formulas together. Weaning commenced between 17 and 26 weeks in 85% centres, ≥26 weeks in 12% and < 17 weeks in 3%. This is the largest European survey completed on PKU infant feeding practices. It is evident that practices varied widely across Europe, and the practicalities of infant feeding in PKU received little focus in the PKU European Guidelines (2017). There are few reports comparing different feeding techniques with blood Phe control, Phe fluctuations and growth. Controlled prospective studies are necessary to assess how different infant feeding practices may influence longer term feeding development.

Background: Recent trials suggested that the Crohn’s disease (CD) exclusion diet (CDED) plus partial enteral nutrition (PEN) is a safe and effective strategy in remission induction of paediatric-onset CD. However, real-world evidence regarding the safety and efficacy of the CDED plus PEN approach is still lacking. The present case-series study reported our experience with the outcomes of CDED plus PEN in the paediatric-onset CD at disease onset and after the loss of response to biologics. Methods: We conducted a retrospective chart review on children who were treated with CDED plus PEN through the period from July 2019 and December 2020. Clinical and laboratory data were retrieved and compared at baseline, 6, 12, and 24 weeks of treatment. The primary endpoint of the present study was the rate of clinical remission. Results: The present study retrieved the data from 15 patients. Of them, nine patients were treatment naïve at the time of initiation of CDED plus PEN (group A) and the remaining patients relapsed on biologics before treatment. All patients in groups A and B exhibited clinical remission in week six, which was sustained until week 12. At the end of the follow-up, the clinical remission rate was 87% and 60% in groups A and B, respectively. No side effects were observed in both groups. In group A, the faecal calprotectin (FC) and albumin improved at week six, week 12, and week 24 (p < 0.05). The erythrocyte sedimentation rate (ESR) improved significantly at week 12 (p = 0.021) and week 24 (p = 0.027). At the same time, the haemoglobin and iron levels showed significant improvement only at week 24. For group B, only FC showed numerical reductions over time that did not reach the level of statistical significance. Conclusion: Treatment with CDED plus PEN was well tolerated and achieved an excellent clinical remission rate in treatment-naive patients. However, the benefit of CDED plus PEN was less in patients who initiated the strategy after losing the response to biologics.

In inborn errors of intermediate protein metabolism (IEM), the effect of special low-protein foods (SLPFs) on dietary intake has been scarcely studied. The aim of this study was to compare the nutritional profile of SLPFs with usual foods and to assess whether their intake determines the dietary pattern and affects the plasma biochemical profile in children with IEMs with different protein restrictions. A database with the nutritional composition of 250 SLPFs was created. A total of 59 children with IEMs were included in this cross-sectional observational study. The greatest significant differences in macronutrient composition were observed between dairy, meat, fish, and egg SLPFs and regular foods. After stratifying subjects by SLPFs, the participants with the highest intake (>32%) had a higher total energy intake and lower intake of natural protein than those in the lowest tertile (<24%) (p < 0.05). However, when stratifying subjects by dairy SLPF intake, children in the highest tertile (>5%) showed a higher intake of sugars, total and saturated fats, and higher plasma levels of total and low-density lipoprotein cholesterol than those in the first tertile (<1%) (p < 0.05). The variability in the nutritional composition of SLPFs highlights the need for up-to-date databases which would greatly assist in optimizing individualized recommendations for children with IEMs and protein restrictions.

Background: Phenylketonuria (PKU) is a rare metabolic disorder caused by a deficiency in the enzyme phenylalanine hydroxylase, leading to the accumulation of phenylalanine (Phe). Raised Phe levels can result in neurocognitive deficits, intellectual disabilities, and behavioral or psychiatric disorders. Aim of review: To conduct a systematic review of human studies on metabolites identified through metabolomics in individuals with PKU, compared to healthy controls, and to provide insights into their biological significance. Key scientific concepts of review: A total of 26 human studies analyzing metabolites in urine and blood met the inclusion criteria. In total, 544 metabolites that differed between patients with PKU and healthy controls were identified through different metabolomic techniques (LC-MS, GC-MS, NMR). Differences were primarily observed in blood samples, which accounted for 95% of the total metabolites, with only 5% detected in urine samples, reflecting the limited use of this body fluid in only five studies. We found 60% of blood metabolites upregulated in patients with PKU, including Phe, Phe-related metabolites, lipids, and other amino acids, while tryptophan and kynurenine, among others, were downregulated (40%). Additionally, 35 metabolites (6% of the total) exhibited inconsistent directions of change (both up- and downregulated), including amino acids, carnitine derivatives, and lipids. These findings may be attributed to clinical factors (dietary adherence, supplementation, and treatment) and methodological differences in blood-derived matrices. Consequently, the high heterogeneity across studies, biological matrices and analytical platforms represents limitations for establishing a unique metabolomic signature. Overall, these results emphasize the metabolic complexity of PKU and highlight the potential of metabolomics to advance disease monitoring and management.

Background/Objectives: Hereditary fructose intolerance (HFI) is an inherited metabolic disorder caused by a deficiency of the enzyme fructose-1,6-bisphosphate aldolase. Treatment consists of a lifelong diet restricted in fructose, sucrose, and sorbitol (FSS). The aim of this study was to determine dietary intake of FSS and to analyze the consumption patterns of vegetables, fruit, legumes, pulses, and dried fruit in a nationwide cohort of HFI patients. Methods: Overall, 36 HFI patients and 28 age-, sex- and BMI-matched healthy control subjects participated in this study. A self-administered three-day dietary record and an adapted quantitative food frequency questionnaire (FFQ) including frequency and portion sizes were collected. FSS intake was calculated using the DIAL Nutritional Calculation Program (ALCE INGENIERÍA). Total fructose intake was calculated as the sum of free fructose, 50% of sucrose, and sorbitol. Results: Protein intake was significantly higher in HFI patients compared to the controls (92.43 g/day [65.1–165.03] vs. 70.39 g/day [35.21–133.83]; p = 0.001). In most patients, total fructose intake was within the recommended limits (9.79 mg/kg bw/day [0.29–59.09]), with no significant differences between children and adults (p = 0.325). Although the established dietary recommendations did not always match the actual intake observed in a real-life setting, in general, foods with higher fructose content were consumed less frequently and in smaller quantities. Conclusions: Further research on the fructose content of various foods, particularly fruits and vegetables, and updated dietary recommendations for HFI patients are warranted to provide the best tools for the nutritional management of the disease.