{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:51:06Z","timestamp":1787028666976,"version":"build-2736575974"},"reference-count":34,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T00:00:00Z","timestamp":1770940800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"IPN","award":["SIP20240889"],"award-info":[{"award-number":["SIP20240889"]}]},{"name":"IPN","award":["SIP20240919"],"award-info":[{"award-number":["SIP20240919"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: In the context of long COVID, persistent fatigue is among the most prevalent symptoms that can develop after SARS-CoV-2 infection. Mitochondrial myopathy and endothelial dysfunction, which are triggers of inflammation, have emerged as prominent causes of long COVID-induced fatigue. Interestingly, the intake of flavanols, particularly (\u2212)-epicatechin (EC), has been associated with the positive modulation of endothelial and mitochondrial structure and function. Methods: In this work, we conducted a randomized, double-blind, placebo-controlled clinical trial to determine whether an EC-enriched supplement (ECES) improves plasma markers of inflammation, endothelial structure, and fatigue-related endpoints in patients with long COVID-19. Results: The study included 46 subjects (mean age 52 years) who were instructed to consume two capsules\/day for 90 days of either ECES (n = 23) or placebo (n = 23). Endpoints assessed included mean changes in plasma inflammatory markers (IL-1\u03b2, IL-6, and TNF-\u03b1) and endothelial dysfunction markers (syndecan-1), handgrip strength, fatigue scale, and quality of life (QoL). The results showed significant improvements in the ECES group for inflammatory markers, syndecan-1, and fatigue compared with the placebo group. Conclusions: The results yield intriguing positive findings for EC and open a new avenue for treating long COVID.<\/jats:p>","DOI":"10.3390\/jcm15041468","type":"journal-article","created":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T09:09:19Z","timestamp":1770973759000},"page":"1468","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effects of Cacao Flavonoids in Long COVID-19 Patients with Chronic Fatigue: FLALOC, a Placebo-Controlled Randomized Clinical Trial"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7785-6099","authenticated-orcid":false,"given":"Levy","family":"Mungu\u00eda","sequence":"first","affiliation":[{"name":"Cl\u00ednica de Especialidades Indianilla, Instituto de Seguridad y Servicios Sociales para los Trabajadores del Estado, Mexico City 06720, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Selene","family":"Silva","sequence":"additional","affiliation":[{"name":"Cl\u00ednica de Especialidades Indianilla, Instituto de Seguridad y Servicios Sociales para los Trabajadores del Estado, Mexico City 06720, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francisco","family":"Villarreal","sequence":"additional","affiliation":[{"name":"VA San Diego Health Care, San Diego, CA 92093, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6869-8762","authenticated-orcid":false,"given":"Nayelli","family":"N\u00e1jera","sequence":"additional","affiliation":[{"name":"Secci\u00f3n de Estudios de Posgrado e Investigaci\u00f3n, Escuela Superior de Medicina, Instituto Polit\u00e9cnico Nacional, Mexico City 11340, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2155-3934","authenticated-orcid":false,"given":"Guillermo","family":"Ceballos","sequence":"additional","affiliation":[{"name":"Secci\u00f3n de Estudios de Posgrado e Investigaci\u00f3n, Escuela Superior de Medicina, Instituto Polit\u00e9cnico Nacional, Mexico City 11340, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1016\/j.cyto.2008.07.009","article-title":"Innate immune response to viral infection","volume":"43","author":"Koyama","year":"2008","journal-title":"Cytokine"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e59177","DOI":"10.7554\/eLife.59177","article-title":"A mechanistic model and therapeutic interventions for COVID-19 involving a RAS-mediated bradykinin storm","volume":"9","author":"Garvin","year":"2020","journal-title":"eLife"},{"key":"ref_3","first-page":"e0144","article-title":"Inflammation profiling of critically ill coronavirus disease 2019 patients","volume":"2","author":"Fraser","year":"2020","journal-title":"Crit. 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