{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,12]],"date-time":"2026-09-12T23:01:06Z","timestamp":1789254066416,"version":"build-2803163510"},"reference-count":39,"publisher":"Elsevier BV","issue":"1","license":[{"start":{"date-parts":[[2020,1,1]],"date-time":"2020-01-01T00:00:00Z","timestamp":1577836800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2023,1,31]],"date-time":"2023-01-31T00:00:00Z","timestamp":1675123200000},"content-version":"vor","delay-in-days":1126,"URL":"http:\/\/www.elsevier.com\/open-access\/userlicense\/1.0\/"}],"content-domain":{"domain":["elsevier.com","sciencedirect.com"],"crossmark-restriction":true},"short-container-title":["The American Journal of Clinical Nutrition"],"published-print":{"date-parts":[[2020,1]]},"DOI":"10.1093\/ajcn\/nqz228","type":"journal-article","created":{"date-parts":[[2019,8,27]],"date-time":"2019-08-27T07:32:45Z","timestamp":1566891165000},"page":"178-186","update-policy":"https:\/\/doi.org\/10.1016\/elsevier_cm_policy","source":"Crossref","is-referenced-by-count":44,"title":["Tryptophan catabolites as metabolic markers of vitamin B-6 status evaluated in cohorts of healthy adults and cardiovascular patients"],"prefix":"10.1016","volume":"111","author":[{"given":"Arve","family":"Ulvik","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u00d8ivind","family":"Midttun","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adrian","family":"McCann","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Klaus","family":"Meyer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Grethe","family":"Tell","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ottar","family":"Nyg\u00e5rd","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Per M","family":"Ueland","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"78","reference":[{"key":"10.1093\/ajcn\/nqz228_bib1","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1186\/1471-2105-10-273","article-title":"The B6 database: a tool for the description and classification of vitamin B6-dependent enzymatic activities and of the corresponding protein families","volume":"10","author":"Percudani","year":"2009","journal-title":"BMC Bioinformatics."},{"key":"10.1093\/ajcn\/nqz228_bib2","doi-asserted-by":"crossref","first-page":"1417","DOI":"10.3945\/ajcn.115.126342","article-title":"Vitamin B-6 catabolism and long-term mortality risk in patients with coronary artery disease","volume":"103","author":"Ulvik","year":"2016","journal-title":"Am J Clin Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib3","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1017\/S0007114511000407","article-title":"Vitamin B6: a challenging link between nutrition and inflammation in CVD","volume":"106","author":"Lotto","year":"2011","journal-title":"Br J Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib4","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1161\/01.STR.0000106481.59944.2F","article-title":"Inflammation, homocysteine, and vitamin B6 status after ischemic stroke","volume":"35","author":"Kelly","year":"2004","journal-title":"Stroke."},{"key":"10.1093\/ajcn\/nqz228_bib5","doi-asserted-by":"crossref","first-page":"2377","DOI":"10.1001\/jama.2010.808","article-title":"Serum B vitamin levels and risk of lung cancer","volume":"303","author":"Johansson","year":"2010","journal-title":"JAMA."},{"key":"10.1093\/ajcn\/nqz228_bib6","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1093\/ajcn\/20.6.547","article-title":"Biochemical and physiological changes in vitamin B6 deficiency","volume":"20","author":"Linkswiler","year":"1967","journal-title":"Am J Clin Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib7","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1111\/j.1749-6632.1969.tb46371.x","article-title":"The tryptophan load as a test for pyridoxine deficiency in hospitalized patients","volume":"166","author":"Coon","year":"1969","journal-title":"Ann N Y Acad Sci."},{"key":"10.1093\/ajcn\/nqz228_bib8","first-page":"179","article-title":"Pyridoxin dependency in two mentally retarded subjects","volume":"24","author":"O\u2019Brien","year":"1963","journal-title":"Clin Sci."},{"key":"10.1093\/ajcn\/nqz228_bib9","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1097\/MCO.0b013e328349f9a7","article-title":"Indicators and methods for folate, vitamin B-12, and vitamin B-6 status assessment in humans","volume":"14","author":"Lamers","year":"2011","journal-title":"Curr Opin Clin Nutr Metab Care."},{"key":"10.1093\/ajcn\/nqz228_bib10","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1146\/annurev-nutr-071714-034330","article-title":"Direct and functional biomarkers of vitamin B6 status","volume":"35","author":"Ueland","year":"2015","journal-title":"Annu Rev Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib11","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1111\/nure.12014","article-title":"Mechanistic perspective on the relationship between pyridoxal 5\u2032-phosphate and inflammation","volume":"71","author":"Paul","year":"2013","journal-title":"Nutr Rev."},{"key":"10.1093\/ajcn\/nqz228_bib12","doi-asserted-by":"crossref","first-page":"611","DOI":"10.3945\/jn.110.133082","article-title":"Low plasma vitamin B-6 status affects metabolism through the kynurenine pathway in cardiovascular patients with systemic inflammation","volume":"141","author":"Midttun","year":"2011","journal-title":"J Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib13","doi-asserted-by":"crossref","first-page":"934","DOI":"10.3945\/ajcn.113.064998","article-title":"Substrate product ratios of enzymes in the kynurenine pathway measured in plasma as indicators of functional vitamin B-6 status","volume":"98","author":"Ulvik","year":"2013","journal-title":"Am J Clin Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib14","doi-asserted-by":"crossref","first-page":"2425","DOI":"10.1002\/ijc.31215","article-title":"Impaired functional vitamin B6 status is associated with increased risk of lung cancer","volume":"142","author":"Theofylaktopoulou","year":"2018","journal-title":"Int J Cancer."},{"key":"10.1093\/ajcn\/nqz228_bib15","doi-asserted-by":"crossref","first-page":"897","DOI":"10.3945\/ajcn.116.139337","article-title":"Vitamin B-6 and colorectal cancer risk: a prospective population-based study using 3 distinct plasma markers of vitamin B-6 status","volume":"105","author":"Gylling","year":"2017","journal-title":"Am J Clin Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib16","doi-asserted-by":"crossref","first-page":"1366","DOI":"10.3945\/ajcn.117.164012","article-title":"Functional vitamin B-6 status and long-term mortality in renal transplant recipients","volume":"106","author":"Minovi\u0107","year":"2017","journal-title":"Am J Clin Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib17","doi-asserted-by":"crossref","first-page":"770","DOI":"10.1093\/jn\/nxz001","article-title":"Vitamin B-6 status correlates with disease activity in rheumatoid arthritis patients during treatment with TNF\u03b1 inhibitors","volume":"149","author":"Sande","year":"2019","journal-title":"J Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib18","doi-asserted-by":"crossref","first-page":"1731S","DOI":"10.1093\/jn\/136.6.1731S","article-title":"The Hordaland Homocysteine Study: a community-based study of homocysteine, its determinants, and associations with disease","volume":"136","author":"Refsum","year":"2006","journal-title":"J Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib19","doi-asserted-by":"crossref","first-page":"709","DOI":"10.1080\/00365510410003057","article-title":"Distribution and determinants of serum creatinine in the general population: the Hordaland Health Study","volume":"64","author":"Vikse","year":"2004","journal-title":"Scand J Clin Lab Invest."},{"key":"10.1093\/ajcn\/nqz228_bib20","doi-asserted-by":"crossref","first-page":"2041","DOI":"10.1161\/ATVBAHA.113.301714","article-title":"Plasma dimethylglycine and risk of incident acute myocardial infarction in patients with stable angina pectoris","volume":"33","author":"Svingen","year":"2013","journal-title":"Arterioscler Thromb Vasc Biol."},{"key":"10.1093\/ajcn\/nqz228_bib21","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1001\/jama.300.7.795","article-title":"Mortality and cardiovascular events in patients treated with homocysteine-lowering B vitamins after coronary angiography: a randomized controlled trial","volume":"300","author":"Ebbing","year":"2008","journal-title":"JAMA."},{"key":"10.1093\/ajcn\/nqz228_bib22","doi-asserted-by":"crossref","first-page":"1435","DOI":"10.2105\/AJPH.77.11.1435","article-title":"Comparison of tests used to distinguish smokers from nonsmokers","volume":"77","author":"Jarvis","year":"1987","journal-title":"Am J Public Health."},{"key":"10.1093\/ajcn\/nqz228_bib23","doi-asserted-by":"crossref","first-page":"1371","DOI":"10.1002\/rcm.4013","article-title":"Quantitative profiling of biomarkers related to B-vitamin status, tryptophan metabolism and inflammation in human plasma by liquid chromatography\/tandem mass spectrometry","volume":"23","author":"Midttun","year":"2009","journal-title":"Rapid Commun Mass Spectrom."},{"key":"10.1093\/ajcn\/nqz228_bib24","doi-asserted-by":"crossref","first-page":"2009","DOI":"10.1007\/s00216-012-6602-6","article-title":"High-throughput, low-volume, multianalyte quantification of plasma metabolites related to one-carbon metabolism using HPLC-MS\/MS","volume":"405","author":"Midttun","year":"2013","journal-title":"Anal Bioanal Chem."},{"key":"10.1093\/ajcn\/nqz228_bib25","doi-asserted-by":"crossref","first-page":"5807","DOI":"10.1021\/ac500704y","article-title":"Targeted quantification of C-reactive protein and cystatin C and its variants by immuno-MALDI-MS","volume":"86","author":"Meyer","year":"2014","journal-title":"Anal Chem."},{"key":"10.1093\/ajcn\/nqz228_bib26","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1177\/2047487314529351","article-title":"Elevated plasma dimethylglycine is a risk marker of mortality in patients with coronary heart disease","volume":"22","author":"Svingen","year":"2015","journal-title":"Eur J Prev Cardiol."},{"key":"10.1093\/ajcn\/nqz228_bib27","doi-asserted-by":"crossref","first-page":"1578","DOI":"10.1056\/NEJMoa055227","article-title":"Homocysteine lowering and cardiovascular events after acute myocardial infarction","volume":"354","author":"Bonaa","year":"2006","journal-title":"N Engl J Med."},{"key":"10.1093\/ajcn\/nqz228_bib28","first-page":"1","article-title":"Relative importance for linear regression in R: the package realimpo","volume":"17","author":"Groemping","year":"2007","journal-title":"J Statist Soft."},{"key":"10.1093\/ajcn\/nqz228_bib29","year":"1998"},{"key":"10.1093\/ajcn\/nqz228_bib30","doi-asserted-by":"crossref","first-page":"1446","DOI":"10.1093\/ajcn\/87.5.1446","article-title":"Plasma pyridoxal 5\u2032-phosphate in the US population: the National Health and Nutrition Examination Survey, 2003\u20132004","volume":"87","author":"Morris","year":"2008","journal-title":"Am J Clin Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib31","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1093\/jxb\/eri011","article-title":"Enzymes, metabolites and fluxes","volume":"56","author":"Fell","year":"2005","journal-title":"J Exp Bot."},{"key":"10.1093\/ajcn\/nqz228_bib32","doi-asserted-by":"crossref","first-page":"1065","DOI":"10.1017\/S0007114514001858","article-title":"Vitamins B2 and B6 as determinants of kynurenines and related markers of interferon-\u03b3-mediated immune activation in the community-based Hordaland Health Study","volume":"112","author":"Theofylaktopoulou","year":"2014","journal-title":"Br J Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib33","doi-asserted-by":"crossref","first-page":"e63544","DOI":"10.1371\/journal.pone.0063544","article-title":"Metabolomic analysis reveals extended metabolic consequences of marginal vitamin B-6 deficiency in healthy human subjects","volume":"8","author":"Gregory","year":"2013","journal-title":"PLoS One."},{"key":"10.1093\/ajcn\/nqz228_bib34","doi-asserted-by":"crossref","first-page":"17559","DOI":"10.1038\/s41598-017-17979-7","article-title":"Inhibition of human kynurenine aminotransferase isozymes by estrogen and its derivatives","volume":"7","author":"Jayawickrama","year":"2017","journal-title":"Sci Rep."},{"key":"10.1093\/ajcn\/nqz228_bib35","doi-asserted-by":"crossref","first-page":"282","DOI":"10.1111\/jocd.12508","article-title":"A review of the role of estrogen in dermal aging and facial attractiveness in women","volume":"17","author":"Lephart","year":"2018","journal-title":"J Cosmet Dermatol."},{"key":"10.1093\/ajcn\/nqz228_bib36","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1093\/ajcn\/29.8.847","article-title":"Age differences in vitamin B6 status of 617 men","volume":"29","author":"Rose","year":"1976","journal-title":"Am J Clin Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib37","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1017\/S0007114599000380","article-title":"Plasma pyridoxal phosphate and pyridoxic acid and their relationship to plasma homocysteine in a representative sample of British men and women aged 65 years and over","volume":"81","author":"Bates","year":"1999","journal-title":"Br J Nutr."},{"key":"10.1093\/ajcn\/nqz228_bib38","doi-asserted-by":"crossref","first-page":"1","DOI":"10.4137\/IJTR.S2097","article-title":"Kynurenine pathway metabolites in humans: disease and healthy states","volume":"2","author":"Chen","year":"2009","journal-title":"Int J Tryptophan Res."},{"key":"10.1093\/ajcn\/nqz228_bib39","first-page":"1","article-title":"The kynurenine pathway: a finger in every pie","volume":"24","author":"Savitz","year":"2019","journal-title":"Mol Psychiatry."}],"container-title":["The American Journal of Clinical Nutrition"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0002916522009856?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0002916522009856?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/academic.oup.com\/ajcn\/article-pdf\/111\/1\/178\/31620980\/nqz228.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"http:\/\/academic.oup.com\/ajcn\/article-pdf\/111\/1\/178\/31620980\/nqz228.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,6,2]],"date-time":"2023-06-02T22:07:41Z","timestamp":1685743661000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0002916522009856"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,1]]},"references-count":39,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2020,1]]}},"alternative-id":["S0002916522009856"],"URL":"https:\/\/doi.org\/10.1093\/ajcn\/nqz228","relation":{},"ISSN":["0002-9165"],"issn-type":[{"value":"0002-9165","type":"print"}],"subject":[],"published":{"date-parts":[[2020,1]]},"assertion":[{"value":"Elsevier","name":"publisher","label":"This article is maintained by"},{"value":"Tryptophan catabolites as metabolic markers of vitamin B-6 status evaluated in cohorts of healthy adults and cardiovascular patients","name":"articletitle","label":"Article Title"},{"value":"The American Journal of Clinical Nutrition","name":"journaltitle","label":"Journal Title"},{"value":"https:\/\/doi.org\/10.1093\/ajcn\/nqz228","name":"articlelink","label":"CrossRef DOI link to publisher maintained version"},{"value":"article","name":"content_type","label":"Content Type"},{"value":"Copyright \u00a9 2020 American Society for Nutrition. Published by Elsevier Inc. All rights reserved.","name":"copyright","label":"Copyright"}]}}