As the country continues to deal with COVID-19 in the absence of effective treatments, attention has focused on modalities that may help boost the immune system. A recent review examined the possible role of nutrition or diet components in COVID-19.
Patients infected with SAR-CoV-2 who are vitamin D–deficient do not fare as well as those who are vitamin D–replete, which has led investigators to consider the possible immunomodulatory role of vitamin D. Vitamin D’s potential benefit stems from its ability to stimulate the expression of antimicrobial peptides, which help maintain the integrity of epithelial tight junctions; enhancement of the expression of antioxidant genes leading to a reduction in inflammation; promotion of macrophage and superoxide production; phagocytosis; suppression of T-helper type-1 activity; reduction of proinflammatory cytokine production; enhancement of anti-inflammatory cytokines; and stimulation of suppressive regulatory T-cells.
Vitamin D deficiency has also been implicated in comorbid disease states that are risk factors for the coronavirus infection as well as in advanced age, which has been associated with a poorer outcome from COVID-19. Adequate vitamin D levels may be inversely correlated with C-reactive protein expression, a marker of inflammation, and with a decreased risk of coagulopathy and immunosuppression. Protein targets on SARS-CoV-2 may be regulated by vitamin D. While not yet proven effective in COVID-19, vitamin D use has been associated with a reduction in the incidence and severity of other viral infections and may reduce proinflammatory cytokines, which are associated with more severe disease and increased mortality in COVID-19.
Vitamin C, a scavenger of reactive oxygen species, has antioxidant activities and deficiencies are associated with disturbances in the balance between antioxidant activity and oxidant generation. Vitamin C supplementation may be preventive against viral infections and may reduce their duration and severity. It reduces proinflammatory cytokines, which are activated in COVID-19 and may play a role in cytokine storm; enhances anti-inflammatory cytokines; reduces TNF-alpha levels, a proinflammatory cytokine that may facilitate the entry of SARS-CoV-2 into host cells; and increases IL-10 levels, which in turn reduces inflammation. Vitamin C has a role in sepsis secondary to pneumonia, and COVID-19 patients are at a higher risk of developing pneumonia.
Zinc, a key trace mineral, is thought to have immunomodulatory and antiviral properties. Adverse physiological effects associated with zinc deficiency include an increase in proinflammatory cytokines; remodeling of lung tissue; changes to the cell-barrier function in lung epithelial tissue; reduction in lymphocyte counts; and impairment of lymphocyte function. Zinc interferes with viral synthesis and replication, including that of coronaviruses. In COVID-19, zinc supplementation may reduce symptoms, such as lower respiratory tract infection, by inhibiting viral uncoating, binding, and replication.
Omega-3-fatty acids have been found to have antiviral properties against influenza. Their role in COVID-19 remains controversial with both improvement in oxygenation observed and increased susceptibility to oxidative membrane damage.
Other compounds that may have immunomodulatory effects in COVID-19 include vitamin E, selenium, magnesium, and vitamin A; however, more research is needed in this area.
While information involving COVID-19 is still evolving, understanding the potential mechanisms by which vitamins and supplements may be beneficial in COVID-19 will help pharmacists educate patients about their proper use.
The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.
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