{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:22:23Z","timestamp":1785424943396,"version":"3.56.0"},"reference-count":30,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T00:00:00Z","timestamp":1780617600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Lions Research Foundation Sk\u00e5ne","award":["n.a."],"award-info":[{"award-number":["n.a."]}]},{"DOI":"10.13039\/501100006189","name":"Direkt\u00f6r Albert P\u00e5hlssons Stiftelse f\u00f6r V\u00e4lg\u00f6renhet","doi-asserted-by":"publisher","award":["n.a."],"award-info":[{"award-number":["n.a."]}],"id":[{"id":"10.13039\/501100006189","id-type":"DOI","asserted-by":"publisher"}]},{"award":["n.a."],"award-info":[{"award-number":["n.a."]}],"id":[{"id":"https:\/\/ror.org\/046q3c491","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background: Dietary management of phenylketonuria (PKU) focuses on restricting phenylalanine (Phe) intake. The European PKU guidelines and the PKU Dietary Handbook recommend a simplified PKU diet, allowing unrestricted consumption of many low-Phe foods, called free foods. While this approach may reduce the treatment burden for patients, its implementation varies. This study investigated practices of Swedish metabolic dietitians regarding the simplified diet and the use of free foods for classical PKU (cPKU) and compared these with European recommendations. Methods: A survey was distributed to all metabolic dietitians in Sweden. The survey included questions on professional experience, the use of free foods and the classification of 135 low-protein food items as never, sometimes or always counted in cPKU. Data were summarised descriptively. Results: All 13 eligible dietitians participated. The use of free foods was recommended by 8\/13 dietitians. Of foods classified as free in the PKU Handbook, about one third were commonly restricted in Swedish PKU practice. For 39% of the foods surveyed, no single response option (never, sometimes or always counted) reached &gt;50%, indicating variation in practice. Classification of individual foods partially aligned with their Phe content, but portion size and concerns about excessive Phe intake also influenced advice. Conclusions: Significant variation exists in the dietary management of PKU in Sweden, and the simplified diet approach is not consistently implemented. Dietitians\u2019 concerns about the safety of increased Phe intake from free foods play a central role in this. These findings highlight challenges in incorporating international guidelines into national practice and underscore the need for further research to address dietitians\u2019 safety concerns related to the simplified diet.<\/jats:p>","DOI":"10.3390\/nu18111835","type":"journal-article","created":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T17:18:16Z","timestamp":1780679896000},"page":"1835","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Simplified Diet for PKU: Practices of Swedish Metabolic Dietitians"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-3181-997X","authenticated-orcid":false,"given":"Marika","family":"Kanthe","sequence":"first","affiliation":[{"name":"Section for Pediatrics, Department of Clinical Sciences, Lund University, 221 00 Lund, Sweden"},{"name":"Department of Pediatrics, Skane University Hospital, 221 85 Lund, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-4280-5008","authenticated-orcid":false,"given":"Camilla","family":"Widenberg T\u00f6rnquist","sequence":"additional","affiliation":[{"name":"Theme Women\u2019s Health and Allied Health Professionals, Medical Unit for Allied Health Professionals, Section Pediatric Clinical Nutrition, Karolinska University Hospital, 171 76 Solna, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tom J.","family":"de Koning","sequence":"additional","affiliation":[{"name":"Section for Pediatrics, Department of Clinical Sciences, Lund University, 221 00 Lund, Sweden"},{"name":"Department of Pediatrics, Skane University Hospital, 221 85 Lund, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1038\/s41572-021-00267-0","article-title":"Phenylketonuria","volume":"7","author":"Blau","year":"2021","journal-title":"Nat. Rev. Dis. Primers"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"109125","DOI":"10.1016\/j.ymgme.2025.109125","article-title":"European guidelines on diagnosis and treatment of phenylketonuria: First revision","volume":"145","author":"MacDonald","year":"2025","journal-title":"Mol. Genet. Metab."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Sorensen, L., von Dobeln, U., Ahlman, H., Ohlsson, A., Engvall, M., Naess, K., Backman-Johansson, C., Nordqvist, Y., Wedell, A., and Zetterstrom, R.H. (2020). Expanded Screening of One Million Swedish Babies with R4S and CLIR for Post-Analytical Evaluation of Data. Int. J. Neonatal Screen., 6.","DOI":"10.3390\/ijns6020042"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1016\/j.ajhg.2020.06.006","article-title":"The Genetic Landscape and Epidemiology of Phenylketonuria","volume":"107","author":"Hillert","year":"2020","journal-title":"Am. J. Hum. Genet."},{"key":"ref_5","unstructured":"(2026, April 10). The Swedish Registry for Inherited Metabolic Diseases (RMMS). Statistics. Available online: https:\/\/rmms.se\/statistik\/."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1186\/s13023-020-01391-y","article-title":"PKU dietary handbook to accompany PKU guidelines","volume":"15","author":"MacDonald","year":"2020","journal-title":"Orphanet J. Rare Dis."},{"key":"ref_7","first-page":"57","article-title":"Living with Phenylketonuria: Lessons from the PKU community","volume":"17","author":"Ford","year":"2018","journal-title":"Mol. Genet. Metab. Rep."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Pinto, A., Ahring, K., Almeida, M.F., Ashmore, C., Belanger-Quintana, A., Burlina, A., Coskun, T., Daly, A., van Dam, E., and Dursun, A. (2024). Blood Phenylalanine Levels in Patients with Phenylketonuria from Europe between 2012 and 2018: Is It a Changing Landscape?. Nutrients, 16.","DOI":"10.3390\/nu16132064"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1016\/j.clnu.2009.03.004","article-title":"Dietary management practices in phenylketonuria across European centres","volume":"28","author":"Ahring","year":"2009","journal-title":"Clin. Nutr."},{"key":"ref_10","first-page":"e454","article-title":"Dietary Management Practices in Phenylketonuria: Results of an Italian Multicentric Survey and Comparison with European Guidelines","volume":"1","author":"Giorda","year":"2024","journal-title":"J. Innate Metab."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Evans, S., Adam, S., Adams, S., Allen, H., Ashmore, C., Bailey, S., Banks, J., Churchill, H., Cochrane, B., and Cook, J. (2020). Uniformity of Food Protein Interpretation Amongst Dietitians for Patients with Phenylketonuria (PKU): 2020 UK National Consensus Statements. Nutrients, 12.","DOI":"10.3390\/nu12082205"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1023\/A:1025150901439","article-title":"Free use of fruits and vegetables in phenylketonuria","volume":"26","author":"MacDonald","year":"2003","journal-title":"J. Inherit. Metab. Dis."},{"key":"ref_13","first-page":"131","article-title":"Dietary protein counting as an alternative way of maintaining metabolic control in phenylketonuria","volume":"3","author":"Sweeney","year":"2012","journal-title":"JIMD Rep."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"264","DOI":"10.1016\/j.ymgme.2012.04.016","article-title":"Positive effect of a simplified diet on blood phenylalanine control in different phenylketonuria variants, characterized by newborn BH4 loading test and PAH analysis","volume":"106","author":"Zimmermann","year":"2012","journal-title":"Mol. Genet. Metab."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1038\/ejcn.2011.205","article-title":"Unrestricted consumption of fruits and vegetables in phenylketonuria: No major impact on metabolic control","volume":"66","author":"Rohde","year":"2012","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1038\/ejcn.2013.272","article-title":"Unrestricted fruits and vegetables in the PKU diet: A 1-year follow-up","volume":"68","author":"Rohde","year":"2014","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Ford, S., Ilgaz, F., Hawker, S., Cochrane, B., Hill, M., Ellerton, C., and MacDonald, A. (2023). Amino Acid Analyses of Plant Foods Used in the Dietary Management of Inherited Amino Acid Disorders. Nutrients, 15.","DOI":"10.3390\/nu15102387"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1111\/j.1365-277X.2006.00696.x","article-title":"The determination of phenylalanine content of foods suitable for phenylketonuria","volume":"19","author":"Weetch","year":"2006","journal-title":"J. Hum. Nutr. Diet."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Boyle, F., Lynch, G., Reynolds, C.M., Green, A., Parr, G., Howard, C., Knerr, I., and Rice, J. (2024). Determination of the Protein and Amino Acid Content of Fruit, Vegetables and Starchy Roots for Use in Inherited Metabolic Disorders. Nutrients, 16.","DOI":"10.3390\/nu16172812"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"22538","DOI":"10.1038\/s41598-025-06633-2","article-title":"Nutritional profiling of foods for Phenylketonuria","volume":"15","author":"Lubina","year":"2025","journal-title":"Sci. Rep."},{"key":"ref_21","unstructured":"Swedish Food Agency (2025, December 09). Amino Acid Content of Foods (Per 100 g Food), Available online: https:\/\/www.livsmedelsverket.se\/livsmedel-och-innehall\/naringsamne\/livsmedelsdatabasen\/."},{"key":"ref_22","unstructured":"(2025, December 09). U.S. Department of Agriculture ARS. FoodData Central, Available online: https:\/\/fdc.nal.usda.gov\/."},{"key":"ref_23","unstructured":"(2026, March 27). Frida Food Data: Technical University of Denmark. Available online: https:\/\/frida.fooddata.dk."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"e70089","DOI":"10.1002\/jimd.70089","article-title":"Overview of European Practices for Management of Tyrosinemia Type 1: Towards European Guidelines","volume":"48","author":"Kuypers","year":"2025","journal-title":"J. Inherit. Metab. Dis."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"454","DOI":"10.1016\/j.ymgme.2013.10.003","article-title":"Dietary practices in pyridoxine non-responsive homocystinuria: A European survey","volume":"110","author":"Adam","year":"2013","journal-title":"Mol. Genet. Metab."},{"key":"ref_26","first-page":"16","article-title":"Dietary practices in isovaleric acidemia: A European survey","volume":"12","author":"Pinto","year":"2017","journal-title":"Mol. Genet. Metab. Rep."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1136\/adc.74.5.412","article-title":"Factors affecting the variation in plasma phenylalanine in patients with phenylketonuria on diet","volume":"74","author":"MacDonald","year":"1996","journal-title":"Arch. Dis. Child."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Pinto, A., Daly, A., Rocha, J.C., Ashmore, C., Evans, S., Jackson, R., Payne, A., Hickson, M., and MacDonald, A. (2022). Impact of Fruit and Vegetable Protein vs. Milk Protein on Metabolic Control of Children with Phenylketonuria: A Randomized Crossover Controlled Trial. Nutrients, 14.","DOI":"10.3390\/nu14204268"},{"key":"ref_29","first-page":"83","article-title":"Simplified Diet for nutrition management of phenylketonuria: A survey of U.S. metabolic dietitians","volume":"53","author":"Hansen","year":"2020","journal-title":"JIMD Rep."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1186\/s13023-017-0685-2","article-title":"The complete European guidelines on phenylketonuria: Diagnosis and treatment","volume":"12","author":"MacDonald","year":"2017","journal-title":"Orphanet J. Rare Dis."}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/11\/1835\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T04:29:04Z","timestamp":1781152144000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/11\/1835"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,5]]},"references-count":30,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["nu18111835"],"URL":"https:\/\/doi.org\/10.3390\/nu18111835","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,5]]}}}