Cabbage and fermented vegetables:from death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT₁R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT₁R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.
ARIA group Amir Hamzah Abdul Latiff, Baharudin Abdullah, Werner Aberer, Nancy Abusada, Ian Adcock, Alejandro Afani, IoanaAgache, XenofonAggelidis, Jenifer Agustin, Cezmi A. Akdis, Mübeccel Akdis, Mona Al-Ahmad, Abou Al-Zahab Bassam, Hussam Alburdan, Oscar Aldrey-Palacios, Emilio Alvarez Cuesta, Hiba Alwan Salman, Ashraf Alzaabi, Salma Amade, Gene Ambrocio, Rosana Angles, Isabella Annesi-Maesano, Ignacio J Ansotegui, JosepAnto, Paula Ara Bardajo, Stefania Arasi, Hasan Arshad, Maria Cristina Artesani, Estrella Asayag, Francesca Avolio, KhuzamaAzhari, Claus Bachert, Diego Bagnasco, Ilaria Baiardini, NisseraBajrović, Petros Bakakos, Sergio BakeyalaMongono, Christine Balotro-Torres, Sergio Barba, Cristina Barbara, Elsa Barbosa, Bruno Barreto, Joan Bartra, Eric D Bateman, LkhagvaaBattur, Anna Bedbrook, Martín Bedolla Barajas, Bianca Beghé, Antra Bekere, Elizabeth Bel, Ali Ben Kheder, Mikael Benson, Elena Camelia Berghea, Karl-Christian Bergmann, Roberto Bernardini, David Bernstein, Mike Bewick, Slawomir Bialek, Artur Białoszewski, Thomas Bieber, Nils E Billo, Maria Beatrice Bilo, Carsten Bindslev-Jensen, Leif Bjermer, Hubert Blain, Irina Bobolea, Malgorzata Bochenska Marciniak, Christine Bond, Attilio Boner, Matteo Bonini, Sergio Bonini, SinthiaBosnic-Anticevich, Isabelle Bosse, Sofia Botskariova, Jacques Bouchard, Louis-Philippe Boulet, Rodolphe Bourret, Philippe Bousquet, FulvioBraido, Andrew Briggs, Christopher E Brightling, Jan Brozek, Luisa Brussino, Roland Buhl, Roxana Bumbacea, Rosalva Buquicchio, María-Teresa Burguete Cabañas, Andrew Bush, William W Busse, Jeroen Buters, Fernan Caballero-Fonseca, Moïses A Calderon, Mario Calvo, Paulo Camargos, Thierry Camuzat, FR Canevari, Antonio Cano, G Walter Canonica, Arnaldo Capriles-Hulett, Luis Caraballo, Vicky Cardona, Kai-Hakon Carlsen, Jonas Carmon Pirez, Jorge Caro, Warner Carr, Pedro Carreiro-Martins, Fredelita Carreon-Asuncion, Ana-Maria Carriazo, Thomas Casale, Mary-Ann Castor, Elizabeth Castro, A.G. Caviglia, Lorenz