{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T20:46:34Z","timestamp":1792097194813,"version":"4.4.0"},"reference-count":45,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[2021,5,3]],"date-time":"2021-05-03T00:00:00Z","timestamp":1620000000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/501100001352","name":"National University of Singapore","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001352","id-type":"DOI","asserted-by":"publisher"}]},{"name":"NUS iHealthtech Microbiome in Health, Disease and Ageing"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2022,1,10]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Context<\/jats:title>\n                  <jats:p>L-tryptophan (Trp) has been documented to aid sleep, but a systematic compilation of its effect on sleep quality is still limited.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Objective<\/jats:title>\n                  <jats:p>We assessed the effect of Trp supplementation on sleep quality via meta-analysis and meta-regression. The effects of daily Trp dose (&amp;lt;1\u2009g and \u22651\u2009g) were also assessed.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Data sources<\/jats:title>\n                  <jats:p>A database search was done in PubMed, Medline (Ovid), Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Cochrane and a total of 18 articles were collected.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Data extraction<\/jats:title>\n                  <jats:p>Extracted data from 4 articles were also analyzed using random-effect meta-analysis and meta-regression. Standardized mean difference (SMD) was used in meta-analysis.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Data analysis<\/jats:title>\n                  <jats:p>Results from the study suggested that Trp supplementation can shorten wake after sleep onset (\u221281.03\u2009min\/g, P = 0.017; SMD, \u22121.08\u2009min [95%CI, \u22121.89 to \u22120.28]). In addition, the group receiving \u22651\u2009g Trp supplementation had a shorter wake after sleep onset than the group with Trp\u2009&amp;lt;\u20091g supplementation (Trp &amp;lt;1\u2009g vs Trp \u22651\u2009g: 56.55 vs 28.91 min; P = 0.001). However, Trp supplementation did not affect other sleep components.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>Trp supplementation, especially at \u22651\u2009g can help improve sleep quality.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/nutrit\/nuab027","type":"journal-article","created":{"date-parts":[[2021,3,13]],"date-time":"2021-03-13T12:10:22Z","timestamp":1615637422000},"page":"306-316","source":"Crossref","is-referenced-by-count":83,"title":["The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression"],"prefix":"10.1093","volume":"80","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7198-2713","authenticated-orcid":false,"given":"Clarinda N","family":"Sutanto","sequence":"first","affiliation":[{"name":"Department of Food Science and Technology, Faculty of Science, National University of Singapore, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wen Wei","family":"Loh","sequence":"additional","affiliation":[{"name":"Department of Food Science and Technology, Faculty of Science, National University of Singapore, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3912-9042","authenticated-orcid":false,"given":"Jung Eun","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Food Science and Technology, Faculty of Science, National University of Singapore, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2021,5,3]]},"reference":[{"key":"2022011217292227800_nuab027-B1","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/j.sleh.2017.07.006","article-title":"Past, present, and future: trends in sleep duration and implications for public 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