Nutrition and Infection with COVID-19
 
Sayyed Saeid Khayyatzadeh; PhD *^{1, 2
 
1} Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
² Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
 

 

Coronavirus disease 2019 (COVID-19) is an acute respiratory disease caused by a newly identified β-coronavirus. It started from Wuhan city of Hubei province of China in December 2019 and spread rapidly throughout the world. This global pandemic has caused dramatic impacts on nations' healthcare systems and socio-economic stability. It transformed into a worldwide public health emergency in a short time. No approved treatment exists for COVID-19 currently, so that the prevention principles are used as the best approach to control this infection. Along with considering environmental, public hygiene, and supportive pharmacological management, it would be crucial to provide adequate hydration and a healthy diet for all individuals. Little data are available on the effect of nutrition on this infection. The common clinical features of COVID-19, include cough, fever (not in all), sore throat, headache, fatigue, headache, lethargy, myalgia, and breathlessness (Guan et al., 2020).  It also has some similar features as other viral diseases, such as seasonal influenza. General nutritional recommendations may be advised for the prevention and management of this new viral disease. Special attention should be paid to promote immune function to enhance the people viral resistance. Specific nutritional deficiencies may result in immune dysfunction leading to increased susceptibility to infectious diseases. Dietary insufficiency of protein, vitamin C, vitamin E, vitamin A, zinc, selenium, and omega-3 fatty acids may also increase its susceptibility, which should be assessed in high-risk groups (Field et al., 2002).

Protein-energy malnutrition (PEM) is a condition that causes immunodeficiency and predisposes infection. Furthermore, infection causes a metabolic disturbance enhancing catabolism. This malnutrition–infection cycle is related to significant morbidity and mortality worldwide, particularly in vulnerable populations (Woodward, 1998). To control PEM, energy and protein requirements should be calculated appropriately and food sources containing high protein and energy are recommended for individuals with a high risk of infection.
The importance of vitamin A in immune function and protection against infections is well established, so that its deficiency is a major public health problem in many developing countries. Vitamin A is involved in maintaining immunity and its deficiency was associated with some viral diseases such as measles and viral diarrhea (Kańtoch et al., 2002). Jee et al. stated that vitamin A supplementation improved disease prognosis and reduced morbidity and mortality in individuals with malaria, lung diseases, and human immunodeficiency virus (HIV) (Jee et al., 2013). Vitamin A deficiency often co-exists with protein-energy malnutrition and its deficiency can be corrected by initial treatment of the PEM (World Health Organization, 2009). Animal sources of protein usually provide good amounts of vitamin A; therefore, high protein diet including fish, meat, poultry, egg, and dairy products should be recommended in the daily meal plan (Gwin et al., 2019).
Vitamin C, present in leukocytes, is rapidly used up during infection. This water-soluble vitamin, as an anti-oxidant increases the immune function strongly and reduces the duration and severity of common cold (Hemilä and Douglas, 1999). Placebo-controlled trials indicated that vitamin C supplementation reduced the incidence of pneumonia and viral respiratory infections (Atherton et al., 1978). In addition, vitamin C has a weak antihistamine effect, which may improve flu-like symptoms such as sneezing, running or stuffy nose, and swollen sinuses (Field et al., 2002). Considering the presence of lower respiratory tract infection in COVID-19, higher dietary intake of vitamin C sources such as citrus fruits and green-leafy vegetables or supplements are recommended (Chambial et al., 2013).
Zinc, a dietary trace element with immunomodulating functions, is vital in generating both acquired and innate antiviral responses (Read et al., 2019). Zinc deficiency is relevant to cell-mediated immunity and H1N1 influenza (Castaño et al., 2006). Administration of zinc was significantly effective in reducing the severity and duration of cold symptoms (Prasad et al., 2000). Zinc supplementation caused beneficial and therapeutic effects for cell-mediated immunity and infection reduction in patients with viral diseases. Based on the previous randomized- clinical trials, co-administration of zinc and antiviral therapy may contribute to improved clinical outcomes in patients with AIDS (Asdamongkol et al., 2013, Baum et al., 2010). Along with intake of zinc supplementation, vulnerable groups were also recommended to consume adequate amounts of rich common dietary sources of zinc such as red meat, poultry, or seafood (Solomons, 2001).
Dietary long-chain poly unsaturated fatty acid (PUFA) derived from fish oil was observed to improve chronic inflammatory and autoimmune disorders (Calder, 1998). However, supplementation with long-chain n-3 PUFA resulted in favorable effects on the immune system and reduced disease severity in animal models. In this regard, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were most beneficial. Controversial effects of consuming fish oil administration on the immune system were reported in humans (Clark and Parbtani, 1994, Das, 1994). In an experimental study, fish oil consumption was associated with increased severity of an influenza virus infection (Schwerbrock et al., 2009). Therefore, n-3 PUFA supplementation may not be safe and advantageous for all people and caution should be taken in n-3 PUFA supplementation in humans. However, dietary intake of n-3 PUFA such as salmon, sardine, canola, walnut, and soy is advisable.
Vitamin E, a lipid soluble antioxidant and selenium, is an essential trace element and the main component of antioxidant defenses. Epidemiological studies demonstrated that deficiencies in either vitamin E or selenium increased viral pathogenicity and altered immune responses (Arthur et al., 2003, Beck, 2007). Vitamin E or selenium supplementation may result in immune benefits, decreased inflammation, and viral load in animal trials (Supúlveda et al., 2002, Tantcheva et al., 2003). Given the limited data over vitamin E or selenium supplementation in human, all individuals should be encouraged to consume adequate dietary intakes of these antioxidants.
In conclusion, no information is available on the association between diet and COVID-19.
In addition, investigations of the nutrients' supplementation have been limited to animal studies and human data are scarce. We recommend all people to consume varied and healthy foods rich in immunomodulating nutrients. In the case that PEM is manifested in individuals, it should be corrected rapidly. Furthermore, some nutrient supplementations such as vitamin C, vitamin E, selenium, and zinc may have beneficial effects on patients with COVID-19.
 
References
Arthur JR, McKenzie RC & Beckett GJ 2003. Selenium in the immune system. Journal of nutrition. 133 (5): 1457S-1459S.
Asdamongkol N, Phanachet P & Sungkanuparph S 2013. Low plasma zinc levels and immunological responses to zinc supplementation in HIV-infected patients with immunological discordance after antiretroviral therapy. Japanese journal of infectious diseases. 66 (6): 469-474.
Atherton J, Kratzing C & Fisher A 1978. The effect of ascorbic acid on infection of chick-embryo ciliated tracheal organ cultures by coronavirus. Archives of virology. 56 (3):195-199.
Baum MK, Lai S, Sales S, Page JB & Campa A 2010. Randomized, controlled clinical trial of zinc supplementation to prevent immunological failure in HIV-infected adults. Clinical infectious diseases. 50 (12): 1653-1660.
Beck MA 2007. Selenium and vitamin E status: impact on viral pathogenicity. Journal of nutrition. 137 (5): 1338-1340.
Calder P 1998. Immunoregulatory and anti-inflammatory effects of n-3 polyunsaturated fatty acids. Brazilian journal of medical and biological research. 31 (4): 467-490.
Castaño PM, Andres R, Lara M & Westhoff C 2006. Assessing feasibility of text messaging to improve medication adherence. Obstetrics & Gynecology. 107 (4): 40S.
Chambial S, Dwivedi S, Shukla KK, John PJ & Sharma P 2013. Vitamin C in disease prevention and cure: an overview. Indian journal of clinical biochemistry. 28 (4): 314-328.
Clark WF & Parbtani A 1994. Omega-3 fatty acid supplementation in clinical and experimental lupus nephritis. American journal of kidney diseases. 23 (5): 644-647.
Das U 1994. Beneficial effect of eicosapentaenoic and docosahexaenoic acids in the management of systemic lupus erythematosus and its relationship to the cytokine network. Prostaglandins, leukotrienes and essential fatty acids. 51 (3): 207-213.
Field CJ, Johnson IR & Schley PD 2002. Nutrients and their role in host resistance to infection. Journal of leukocyte biology. 71 (1): 16-32.
Guan W-j, et al. 2020. Clinical characteristics of coronavirus disease 2019 in China. New England journal of medicine.
Gwin JA, et al. 2019. Higher protein density diets are associated with greater diet quality and micronutrient intake in healthy young adults. Frontiers in nutrition. 6.
Hemilä H & Douglas RM 1999. Vitamin C and acute respiratory infections. International journal of tuberculosis and lung disease. 3 (9): 756-761.
Jee J, et al. 2013. Effects of dietary vitamin A content on antibody responses of feedlot calves inoculated intramuscularly with an inactivated bovine coronavirus vaccine. American journal of veterinary research. 74 (10): 1353-1362.
Kańtoch M, Litwińska B, Szkoda M & Siennicka J 2002. Importance of vitamin A deficiency in pathology and immunology of viral infections. Roczniki panstwowego zakladu higieny. 53 (4): 385-392.
Prasad AS, Fitzgerald JT, Bao B, Beck FW & Chandrasekar PH 2000. Duration of symptoms and plasma cytokine levels in patients with the common cold treated with zinc acetate: a randomized, double-blind, placebo-controlled trial. Annals of internal medicine. 133 (4): 245-252.
Read SA, Obeid S, Ahlenstiel C & Ahlenstiel G 2019. The role of zinc in antiviral immunity. Advances in nutrition. 10 (4): 696-710.
Schwerbrock NM, Karlsson EA, Shi Q, Sheridan PA & Beck MA 2009. Fish oil-fed mice have impaired resistance to influenza infection. Journal of nutrition. 139 (8): 1588-1594.
Solomons NW 2001. Dietary sources of zinc and factors affecting its bioavailability. Food and nutrition bulletin. 22 (2): 138-154.
Supúlveda RT, Zhang J & Watson RR
2002. Selenium supplementation decreases coxsackievirus heart disease during murine AIDS. Cardiovascular toxicology. 2 (1): 53-61.
Tantcheva L, et al. 2003. Effect of vitamin E and vitamin C combination on experimental influenza virus infection. Methods and findings in experimental and clinical pharmacology. 25 (4): 259-264.
Woodward B 1998. Protein, calories, and immune defenses. Nutrition reviews. 56 (1): S84-S92.
World Health Organization 2009. Global prevalence of vitamin A deficiency in populations at risk 1995-2005: WHO global database on vitamin A deficiency.