Abstract: 1 Mediterranean Journal of Nutrition and Metabolism xx (2022) x–xx DOI:10.3233/MNM-211521 IOS Press 2 3 4 The difference in the dietary inflammatory index, functional food, and antioxidants intake between COVID -19 patients and healthy persons roo f 1 Mahsa Mohajeria,b , Reza Mohajeryb,c , Ali Nematia,d,∗ and Farhad Pourfarzia,∗ 6 a Digestive Disease Research Center, Ardabil University of Medical Sciences, Ardabil, Iran 7 b Academic Center for Education, Culture and Research, Ardabil, Iran 8 c Energy Management Research Center, University of Mohaghegh Ardabili, Ardabil, Iran 9 d Department of Clinical Biochemistry, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Au tho rP 5 Iran 10 16 17 18 19 20 21 22 23 24 25 26 27 28 Abstract. BACKGROUND: The healthy diet is important to maintain immunity against infection. This study aimed to assess and compare the consumption of functional foods, some antioxidants, and dietary inflammatory index between Iranian COVID-19 patients and healthy persons. METHODS: This case-control study was conducted between 1000 (500 cases and 500 controls) adults aged 18–65years in Iran, that were sampling based on the snowball method and their information was collected electronically. The dietary intake was assessed using the Food Frequency Questionnaire (FFQ). RESULTS: There was a significant difference (p = 0.044) in vitamin D consumption between healthy people and COVID19 patients. Vitamin E intake in healthy participants was significantly (p = 0.041) more than COVID-19 patients. There was a significant difference in Zinc (p = 0.011), selenium (p = 0.021), and vitamin C (p = 0.023) between healthy persons and COVID-19 patients. Healthy participants’ consumption of onion (56.5 ± 7.82 g/day), garlic (4.32 ± 0.01 g/day) and oat (6.32 ± 0.71 g/day) was significantly (p ≤ 0.05) more than COVID-19 patients. With the increase of each unit in the score of the dietary inflammatory index, the risk of COVID-19 incidence increased 1.63 times (OR = 1.63 95%CI: 1.54–1.72). There was an inverse association between the consumption of antioxidants and functional foods with the risk of COVID-19 incidence in the study population (p ≤ 0.05). cte d 15 rre 14 Received 10 July 2021 Accepted 20 January 2022 Pre-press 29 January 2022 co 13 12 Un 11 ∗ Corresponding author: Ali Nemati, Digestive Disease Research Center, Ardabil University of Medical Sciences, Ardabil, Iran. E-mail: nutrition1391@gmail.com. and Farhad Pourfarzi, Department of Clinical Biochemistry, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran. E-mail: farhad.pourfarzi@gmail.com. ISSN 1973-798X/$35.00 © 2022 – IOS Press. All rights reserved. 2 28 29 30 31 32 M. Mohajeri et al. / The dietary inflammatory index, functional food, and antioxidants intake in COVID -19 patients CONCLUSION: Healthy people consumption of antioxidants and functional foods was more than COVID-19 patients and there was a significant inverse association between the risk of COVID- 19 incidence with the consumption of functional foods and antioxidants. Increasing the dietary inflammatory index score increased the risk of COVID- 19 incidence. There is a need for further clinical trials to confirm the effect of consuming functional foods and antioxidants on the prevention or treatment of COVID-19. 33 34 roo f Keywords: COVID-19, antioxidants, functional foods, dietary inflammatory index