{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,17]],"date-time":"2026-10-17T06:11:26Z","timestamp":1792217486659,"version":"4.4.0"},"reference-count":35,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T00:00:00Z","timestamp":1768694400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004281","name":"National Science Centre","doi-asserted-by":"publisher","award":["2021\/41\/B\/NZ9\/01278"],"award-info":[{"award-number":["2021\/41\/B\/NZ9\/01278"]}],"id":[{"id":"10.13039\/501100004281","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background\/Objectives: Circulating amino acid concentrations and their excretion can provide insights into dietary protein intake and metabolism. Alterations in amino acid homeostasis occur in various disorders due to nutritional imbalances or metabolic changes, including obesity. A ketogenic diet (KD) has gained popularity for weight management; however, its metabolic effects are not fully known. Therefore, the aim of this study was to evaluate the effect of an eight-week, energy-restricted Mediterranean-type KD on the amino acid metabolism in women with overweight and class I obesity. Methods: A randomized, single-center, controlled trial was conducted with 80 women with a BMI of 25.5\u201335 in age between 18 and 45 years, without any chronic diseases. Randomly divided women received food catering with approximately 1750 kcal daily for eight weeks, containing KD or standard diet (STD), respectively. The concentration of amino acids was assessed by gas chromatography-mass spectrometry after the derivatization with chloroformate in serum and urine collected at the baseline, after 4 weeks, and at the end of the intervention. Results: The results collected from 66 participants were included in the final analyses. Independent of diet type, weight reduction was associated with increased circulating \u03b1-aminobutyric acid and decreased proline, glutamate, and tyrosine. The KD led to lower concentrations of alanine, methionine, threonine, and tryptophan, alongside higher levels of branched-chain amino acids (BCAA) and \u03b1-aminobutyric acid compared to the STD. Urinary amino acid excretion decreased after weight reduction. KD was associated with higher urinary excretion of BCAA and \u03b2-aminoisobutyric acid. Conclusions: In summary, both weight reduction and KD significantly affect the amino acid metabolism, which might have implications for inflammation, oxidative stress, and cardiometabolic risk.<\/jats:p>","DOI":"10.3390\/nu18020300","type":"journal-article","created":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T09:57:02Z","timestamp":1768816622000},"page":"300","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Alteration in Amino Acid Metabolism After Isocaloric, Energy-Restricted Ketogenic Diet in Women with Overweight and Obesity: Randomized KETO-MINOX Trial"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5324-5982","authenticated-orcid":false,"given":"Natalia","family":"Drabi\u0144ska-Fois","sequence":"first","affiliation":[{"name":"Food Volatilomics and Sensomics Group, Department of Food Technology of Plant Origin, Faculty of Food Science and Nutrition, Poznan University of Life Sciences, Wojska Polskiego 28, 60-637 Pozna\u0144, Poland"},{"name":"Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10 Str., 10-748 Olsztyn, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Majcher","sequence":"additional","affiliation":[{"name":"Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10 Str., 10-748 Olsztyn, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7583-8965","authenticated-orcid":false,"given":"Pawe\u0142","family":"Jagielski","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Drug Research, Institute of Public Health, Faculty of Health Sciences, Jagiellonian University Medical College, 31-066 Krakow, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sebastian","family":"Borowicz-Skoneczny","sequence":"additional","affiliation":[{"name":"Department of Family Medicine and Infectious Diseases, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7929-6822","authenticated-orcid":false,"given":"Jerzy","family":"Romaszko","sequence":"additional","affiliation":[{"name":"Department of Family Medicine and Infectious Diseases, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1016\/S2213-8587(24)00316-4","article-title":"Definition and Diagnostic Criteria of Clinical Obesity","volume":"13","author":"Rubino","year":"2025","journal-title":"Lancet Diabetes Endocrinol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"219","DOI":"10.31883\/pjfns\/110735","article-title":"The Dose Makes the Poison: Sugar and Obesity in the United States\u2014A Review","volume":"69","author":"Faruque","year":"2019","journal-title":"Pol. J. Food Nutr. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1146\/annurev-publhealth-060922-044108","article-title":"Next Steps in Efforts to Address the Obesity Epidemic","volume":"46","author":"Eneli","year":"2025","journal-title":"Annu. Rev. Public Health"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"S288","DOI":"10.37765\/ajmc.2022.89292","article-title":"A Review of Current Guidelines for the Treatment of Obesity","volume":"28","year":"2022","journal-title":"Am. J. Manag. Care"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"82","DOI":"10.31883\/pjfns\/183995","article-title":"High-Fiber Extruded Purple Sweet Potato (Ipomoea batatas) and Kidney Bean (Phaseolus vulgaris) Extends the Feeling of Fullness","volume":"74","author":"Palupi","year":"2024","journal-title":"Pol. J. Food Nutr. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Koceva, A., Herman, R., Janez, A., Rakusa, M., and Jensterle, M. (2024). Sex- and Gender-Related Differences in Obesity: From Pathophysiological Mechanisms to Clinical Implications. Int. J. Mol. Sci., 25.","DOI":"10.3390\/ijms25137342"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00726-009-0269-0","article-title":"Amino Acids: Metabolism, Functions, and Nutrition","volume":"37","author":"Wu","year":"2009","journal-title":"Amino Acids"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"445","DOI":"10.3945\/an.111.000737","article-title":"Emerging Perspectives on Essential Amino Acid Metabolism in Obesity and the Insulin-Resistant State","volume":"2","author":"Adams","year":"2011","journal-title":"Adv. Nutr."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"100373","DOI":"10.1016\/j.metop.2025.100373","article-title":"Interventional Approaches to Combat Obesity: Exploring the Metabolomic Signature of Weight Loss Trials","volume":"27","author":"Pardali","year":"2025","journal-title":"Metabol. Open"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"587","DOI":"10.14348\/molcells.2015.0126","article-title":"A Metabolomic Approach to Understanding the Metabolic Link between Obesity and Diabetes","volume":"38","author":"Park","year":"2015","journal-title":"Mol. Cells"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"6490473","DOI":"10.1155\/2017\/6490473","article-title":"Amino Acid Signatures to Evaluate the Beneficial Effects of Weight Loss","volume":"2017","author":"Geidenstam","year":"2017","journal-title":"Int. J. Endocrinol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1111\/obr.12230","article-title":"Do Ketogenic Diets Really Suppress Appetite? A Systematic Review and Meta-Analysis","volume":"16","author":"Gibson","year":"2015","journal-title":"Obes. Rev."},{"key":"ref_13","first-page":"92","article-title":"Current Perspective About the Effect of a Ketogenic Diet on Oxidative Stress\u2014A Review","volume":"74","year":"2024","journal-title":"Pol. J. Food Nutr. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.tifs.2021.01.080","article-title":"Recent Advances in the Application of a Ketogenic Diet for Obesity Management","volume":"110","author":"Wiczkowski","year":"2021","journal-title":"Trends Food Sci. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.seizure.2023.03.014","article-title":"Comprehensive Study of Metabolic Changes Induced by a Ketogenic Diet Therapy Using GC\/MS- and LC\/MS-Based Metabolomics","volume":"107","author":"Akiyama","year":"2023","journal-title":"Seizure Eur. J. Epilepsy"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"415","DOI":"10.1146\/annurev.nutr.27.061406.093722","article-title":"The Ketogenic Diet and Brain Metabolism of Amino Acids: Relationship to the Anticonvulsant Effect","volume":"27","author":"Yudkoff","year":"2007","journal-title":"Annu. Rev. Nutr."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1016\/j.eplepsyres.2005.03.008","article-title":"The Ketogenic Diet Influences the Levels of Excitatory and Inhibitory Amino Acids in the CSF in Children with Refractory Epilepsy","volume":"64","author":"Dahlin","year":"2005","journal-title":"Epilepsy Res."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1202","DOI":"10.1016\/j.clnu.2023.04.027","article-title":"A Ketogenic Diet Substantially Reshapes the Human Metabolome","volume":"42","author":"Effinger","year":"2023","journal-title":"Clin. Nutr."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Drabi\u0144ska, N., Romaszko, J., and White, P. (2023). The Effect of Isocaloric, Energy-Restrictive, KETOgenic Diet on Metabolism, Inflammation, Nutrition Deficiencies and Oxidative Stress in Women with Overweight and Obesity (KETO-MINOX): Study Protocol. PLoS ONE, 18.","DOI":"10.1371\/journal.pone.0285283"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Li, F., Xia, Y., Yuan, S., Xie, X., Li, L., Luo, Y., Du, Q., Yuan, Y., and He, R. (2023). \u03b1-Aminobutyric Acid Constrains Macrophage-Associated Inflammatory Diseases through Metabolic Reprogramming and Epigenetic Modification. Int. J. Mol. Sci., 24.","DOI":"10.3390\/ijms241310444"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"36749","DOI":"10.1038\/srep36749","article-title":"2-Aminobutyric Acid Modulates Glutathione Homeostasis in the Myocardium","volume":"6","author":"Irino","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1369","DOI":"10.1038\/ijo.2017.124","article-title":"Metabolite Profiling of Obese Individuals before and after a One Year Weight Loss Program","volume":"41","author":"Geidenstam","year":"2017","journal-title":"Int. J. Obes."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"a040584","DOI":"10.1101\/cshperspect.a040584","article-title":"Amino Acid Metabolism","volume":"13","author":"Chandel","year":"2021","journal-title":"Cold Spring Harb. Perspect. Biol."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Hole\u010dek, M. (2024). Origin and Roles of Alanine and Glutamine in Gluconeogenesis in the Liver, Kidneys, and Small Intestine under Physiological and Pathological Conditions. Int. J. Mol. Sci., 25.","DOI":"10.3390\/ijms25137037"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2091","DOI":"10.1007\/s00726-017-2494-2","article-title":"The Role of Methionine on Metabolism, Oxidative Stress, and Diseases","volume":"49","author":"Li","year":"2017","journal-title":"Amino Acids"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"543","DOI":"10.1089\/ars.2015.6516","article-title":"Methionine Metabolism Alters Oxidative Stress Resistance via the Pentose Phosphate Pathway","volume":"24","author":"Campbell","year":"2016","journal-title":"Antioxid. Redox Signal."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Paoli, A., Bianco, A., Moro, T., Mota, J.F., and Coelho-Ravagnani, C.F. (2023). The Effects of Ketogenic Diet on Insulin Sensitivity and Weight Loss, Which Came First: The Chicken or the Egg?. Nutrients, 15.","DOI":"10.3390\/nu15143120"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Bo, T., and Fujii, J. (2024). Primary Roles of Branched Chain Amino Acids (BCAAs) and Their Metabolism in Physiology and Metabolic Disorders. Molecules, 30.","DOI":"10.3390\/molecules30010056"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"E1552","DOI":"10.1152\/ajpendo.00134.2007","article-title":"Obesity-Related Elevations in Plasma Leucine Are Associated with Alterations in Enzymes Involved in Branched-Chain Amino Acid Metabolism","volume":"293","author":"She","year":"2007","journal-title":"Am. J. Physiol.-Endocrinol. Metab."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1186\/s12937-017-0240-y","article-title":"Diverse Characteristics of the Urinary Excretion of Amino Acids in Humans and the Use of Amino Acid Supplementation to Reduce Fatigue and Sub-Health in Adults","volume":"16","author":"Dunstan","year":"2017","journal-title":"Nutr. J."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Coker, M.S., and Coker, R.H. (2025). Dietary Proteins, Amino Acids and Insulin Resistance: A Mini Review. Front. Nutr., 12.","DOI":"10.3389\/fnut.2025.1671286"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1111\/j.1472-8206.2009.00765.x","article-title":"Effects of \u0392-aminoisobutyric Acid on Leptin Production and Lipid Homeostasis: Mechanisms and Possible Relevance for the Prevention of Obesity","volume":"24","author":"Begriche","year":"2010","journal-title":"Fundam. Clin. Pharmacol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1016\/j.cmet.2013.12.003","article-title":"\u03b2-Aminoisobutyric Acid Induces Browning of White Fat and Hepatic \u03b2-Oxidation and Is Inversely Correlated with Cardiometabolic Risk Factors","volume":"19","author":"Roberts","year":"2014","journal-title":"Cell Metab."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1159\/000517305","article-title":"Starvation Ketosis and the Kidney","volume":"52","author":"Palmer","year":"2021","journal-title":"Am. J. Nephrol."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Buga, A., Kackley, M.L., Crabtree, C.D., Sapper, T.N., Mccabe, L., Fell, B., LaFountain, R.A., Hyde, P.N., Martini, E.R., and Bowman, J. (2021). The Effects of a 6-Week Controlled, Hypocaloric Ketogenic Diet, With and Without Exogenous Ketone Salts, on Body Composition Responses. Front. Nutr., 8.","DOI":"10.3389\/fnut.2021.618520"}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/2\/300\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T10:02:30Z","timestamp":1768816950000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/2\/300"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,18]]},"references-count":35,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["nu18020300"],"URL":"https:\/\/doi.org\/10.3390\/nu18020300","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,18]]}}}