Do Diet and Dietary Supplements Mitigate Clinical Outcomes in COVID-19?

Abstract

The coronavirus disease 2019 (COVID-19) has caused a pandemic and upheaval that health authorities and citizens around the globe are still grappling with to this day. While public health measures, vaccine development, and new therapeutics have made great strides in understanding and managing the pandemic, there has been an increasing focus on the potential roles of diet and supplementation in disease prevention and adjuvant treatment. In the literature, the impact of nutrition on other respiratory illnesses, including the common cold, pneumonia, and influenza, has been widely demonstrated in both animal and human models. However, there is much less research on the impact related to COVID-19. The present study discusses the potential uses of diets, vitamins, and supplements, including the Mediterranean diet, glutathione, zinc, and traditional Chinese medicine, in the prevention of infection and severe illness. The evidence demonstrating the efficacy of diet supplementation on infection risk, disease duration, severity, and recovery is mixed and inconsistent. More clinical trials are necessary in order to clearly demonstrate the contribution of nutrition and to guide potential therapeutic protocols.

Susceptibility to COVID-19 Nutrition Misinformation and Eating Behavior Change during Lockdowns: An International Web-Based Survey

“…Vitamins C and D, alongside other essential nutrients, can help with the ‘maintenance of functions of the immune system’ (European Food Safety Authority, EFSA) [ 57 ]; thus, mitigating deficiency risks for these during the early stages of the novel coronavirus pandemic was emphasized [ 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ]. Research on vitamin C and vitamin D status remains ongoing on the grounds that their deficiency may be associated with increased susceptibility to COVID-19 infection and to potentially more severe or prolonged symptoms once infected [ 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 ]. Because medical prescription is not needed for their procurement, misinformed assurances with silent contraindications about vitamin supplements could lead to harmful intakes, unsafe combinations, and misuse by the public, as seen in hypervitaminosis and intoxication case reports during the global pandemic [ 36 , 83 , 84 , 85 , 86 , 87 , 88 , 89 ].…”

Associations between self-reported symptoms of SARS-CoV-2 and dietary supplement use over the previous year during the first pandemic wave

“…Evidence does, however, support the importance of obtaining adequate amounts of the micronutrient examined in this study for proper immune function. Because deficiencies may predispose individuals to infections, it is important to ingest adequate amounts of these micronutrients within the food matrix ( 4 , 5 , 6 ) . However, the Office of Dietary Supplements at the National Institutes of Health states, ‘current data are insufficient to support recommendations for or against the use of any vitamin, mineral, herb, other botanical, fatty acid, or other dietary supplement ingredient to prevent or treat COVID-19’ ( 35 ) .…”

“…Data from our study support current public health statements. Although a nutrient-dense diet should be encouraged to prevent malnutrition and micronutrient deficiencies ( 4 , 5 , 6 ) , no magic bullet vitamin or mineral supplement exists to protect against infection or specific symptoms ( 16 ) .…”

“…Nutrient deficiencies can predispose people to respiratory illnesses and other infections ( 4 , 5 ) . Specific vitamins and minerals are important for immune function, and as COVID-19 will likely become endemic in many areas, the possible protective role of micronutrients is of great interest ( 6 ) . Vitamins D, C, E and zinc have garnered particular attention.…”

“…Vitamin D stimulates production of antimicrobial peptides ( 9 , 10 ) , and it may protect against overproduction of cytokines and the so-called cytokine storm ( 7 , 8 ) . Although studies examining vitamin D supplementation to treat COVID-19 infection have shown mixed results ( 6 ) , low blood concentrations of 25-hydroxyvitamin D are associated with increased risk of infection ( 11 ) and more severe illness in those infected with SARS-CoV-2 ( 6 ) . However, two large studies from Europe recently reported that prophylactic supplementation of vitamin D failed to prevent SARS-CoV-2 infection ( 12 , 13 ) .…”