{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T02:29:35Z","timestamp":1768703375711,"version":"3.49.0"},"reference-count":32,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,4,29]],"date-time":"2022-04-29T00:00:00Z","timestamp":1651190400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Corporation (Tokyo, Japan)"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Tea catechins are plant-derived compounds that improve immune functions. Previous randomized control trials have demonstrated the efficacy of primarily epi-type catechins against upper respiratory tract infections (URTIs). Green tea can be consumed in several ways, including popular bottled beverages. These beverages, however, require sterilization during manufacturing, which results in catechin isomerization. We conducted a randomized, double-blinded, placebo-controlled trial involving healthy Japanese participants to evaluate whether catechin consumption via bottled beverages has an alleviating effect on the duration and severity of URTIs in winter. The catechin group (490 mg catechin, 0.14%, containing 59% epi-type catechin, n = 55) showed reduced durations of running nose, nasal congestion, and headache, compared with the placebo group (0 mg catechin, n = 54; p = 0.013, 0.018, and &lt;0.001, respectively). Furthermore, when considering physical symptoms, the duration of nasopharyngeal symptoms improved significantly in the catechin group (p &lt; 0.001) compared with that in the control group. The daily consumption of catechin thus reduced the duration and severity of URTIs in healthy men and women. Humans are regularly exposed to several potential infectious threats, and the oral administration of heat-epimerized tea catechins might help prevent and reduce the severity of URTIs.<\/jats:p>","DOI":"10.3390\/nu14091856","type":"journal-article","created":{"date-parts":[[2022,5,2]],"date-time":"2022-05-02T07:08:58Z","timestamp":1651475338000},"page":"1856","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Effect of Catechins on Upper Respiratory Tract Infections in Winter: A Randomized, Placebo-Controlled, Double-Blinded Trial"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2038-4705","authenticated-orcid":false,"given":"Naoki","family":"Ozato","sequence":"first","affiliation":[{"name":"Health & Wellness Products Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5946-1042","authenticated-orcid":false,"given":"Tohru","family":"Yamaguchi","sequence":"additional","affiliation":[{"name":"Health & Wellness Products Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tatsuya","family":"Kusaura","sequence":"additional","affiliation":[{"name":"Health & Wellness Products Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hidefumi","family":"Kitazawa","sequence":"additional","affiliation":[{"name":"Biological Science Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masanobu","family":"Hibi","sequence":"additional","affiliation":[{"name":"Biological Science Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Noriko","family":"Osaki","sequence":"additional","affiliation":[{"name":"Health & Wellness Products Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takahiro","family":"Ono","sequence":"additional","affiliation":[{"name":"Ueno-Asagao Clinic, Tokyo 110-0015, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"S1","DOI":"10.1093\/cid\/ciq005","article-title":"2009 H1N1 Influenza Pandemic: Field and Epidemiologic Investigations in the United States at the Start of the First Pandemic of the 21st Century","volume":"52","author":"Swerdlow","year":"2011","journal-title":"Clin. 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