Abstract: nutrients Article Associations of Nutritional Behavior and Gut Microbiota with the Risk of COVID-19 in Healthy Young Adults in Poland Paweł Jagielski 1, * , Edyta Łuszczki 2 , Dominika Wn˛ek 3 , Agnieszka Micek 4 , Izabela Bolesławska 5 , Beata Piórecka 1 and Paweł Kawalec 1 1 2 3 4 5 *



 Citation: Jagielski, P.; Łuszczki, E.; Wn˛ek, D.; Micek, A.; Bolesławska, I.; Piórecka, B.; Kawalec, P. Associations of Nutritional Behavior and Gut Microbiota with the Risk of COVID-19 in Healthy Young Adults in Poland. Nutrients 2022, 14, 350. https://doi.org/10.3390/ nu14020350 Academic Editor: Department of Nutrition and Drug Research, Institute of Public Health, Faculty of Health Sciences, Jagiellonian University Medical College, 31-066 Krakow, Poland; beata.piorecka@uj.edu.pl (B.P.); pawel.kawalec@uj.edu.pl (P.K.) Institute of Health Sciences, Medical College of Rzeszow University, 35-959 Rzeszów, Poland; eluszczki@ur.edu.pl The Cracow’s Higher School of Health Promotion, 31-158 Krakow, Poland; dsiedlec@cm-uj.krakow.pl Department of Nursing Management and Epidemiology Nursing, Jagiellonian University Medical College, 31-007 Cracow, Poland; agnieszka.micek@uj.edu.pl Department of Bromatology, Poznan University of Medical Sciences, 42 Marcelińska Str., 60-354 Poznań, Poland; ibolesla@ump.edu.pl Correspondence: paweljan.jagielski@uj.edu.pl; Tel.: +48-12-433-28-20 Abstract: The numerous consequences of the coronavirus disease 2019 (COVID-19) pandemic in healthy young people and the lack of clarity as to the long-term disease outcomes have spurred the search for risk factors for SARS-CoV-2 infection. We aimed to evaluate the associations of nutritional behaviors, gut microbiota, and physical activity with the risk of COVID-19 in healthy young nonobese people. Data on body composition, anthropometric measurements, physical activity, dietary intake, and gut microbiota were obtained from 95 adults (mean age, 34.66 ± 5.76 years). A balanced diet rich in vegetables and fruit, including nuts, wholegrain cereal products, and legumes, covers the need for vitamins and minerals. Such a diet can be an effective measure to reduce the risk of COVID-19 in nonobese healthy physically active young people with normal immune function. People with balanced diet and an average daily consumption of >500 g of vegetables and fruit and >10 g of nuts had an 86% lower risk of COVID-19 compared with those whose diet was not balanced and who consumed lower amounts of these products. It is well documented that proper nutrition, physical activity, and maintenance of normal weight facilitate good health by ensuring optimal immune function. The beneficial effects of these interventions should be strongly emphasized during the COVID-19 pandemic. Giovanna Muscogiuri Received: 22 December 2021 Accepted: 11 January 2022 Keywords: COVID-19 pandemic; dietary intake; Dietary Inflammatory Index; gut microbiota; nutrition; physical activity Published: 14 January 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).