These Nutritional Supplements May Help Prevent or Mitigate COVID-19 Severity

In 30 seconds…

With hundreds of thousands of new cases being reported every day, over a year after its onset, the coronavirus disease 2019 (COVID-19) pandemic is still making its presence felt worldwide. Caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pandemic is estimated to be about ten-fold bigger than the number of reported infections.

A new study in the Journal of dietary supplements shows that nutritional supplements, including several vitamins and the mineral zinc, may be useful in preventing the infection or reducing its severity if caught.

Vitamin C

Vitamin C is a very safe molecule. Its antioxidant activity is particularly effective in light of the high inflammatory and oxidative markers in COVID-19, especially hsCRP, and the cytokine storm, which is another marker of oxidative stress.

In one study of patients in an intensive care unit (ICU), and patients on mechanical ventilation because of acute inflammatory lung disease associated with oxidant damage, the use of vitamin C reduced the duration spent in the ICU and the outcome in ventilated patients.

One Chinese study showed that boluses of vitamin C given by intravenous infusion to COVID-19 patients, with repeated boluses if the condition was critical, improved the oxygenation status. All patients under treatment were discharged to home. Controlled trials of vitamin C therapy in patients hospitalized with severe COVID-19 are underway.

Vitamin D

Vitamin D also has a vital role in immunity, as its active form interacts with the vitamin D receptor (VDR) on the nucleus of immune cells. It stimulates the generation of antimicrobial peptides, such as cathelicidins and defensins, broad-spectrum agents against a range of pathogens, thus bolstering innate immune responses.

Recent studies indicate that in vitamin D-deficient people, vitamin D supplementation may help reduce the risk of respiratory infections. With COVID-19, the risk of being diagnosed with this condition was 1.8 times higher with vitamin D deficiency relative to adequate vitamin D status. The risk of hospitalization may also be higher in the former group.

Vitamin D reduces angiotensin-converting enzyme 2 (ACE2) levels. This molecule acts as an entry receptor for SARS-CoV-2, and at higher levels, it may increase vulnerability to more severe manifestations.

Based on these findings, vitamin D intake has been advised in COVID-19 patients to push the serum concentrations above 40–60 ng/mL. Trials are ongoing to investigate the role of vitamin D.


Zinc is commonly present in every tissue and metallo-enzyme in the body but is deficient in about a third of human beings worldwide. Insufficient zinc intake has been linked to many health conditions, including skin disorders and cognitive issues. Immune function is also impaired. Phytate and fiber in the diet can reduce zinc absorption, putting those on a strictly vegetarian diet at a higher risk of zinc deficiency. This is also found in several chronic disease conditions.

Zinc is involved in innate and adaptive immune responses, from immune cell development onwards, through mucosal integrity. Supplementation with zinc has been found to reduce respiratory infections in children, and to cut short colds by a day.

Studies are ongoing to test the effects of zinc supplementation in COVID-19.

Vitamin B3

Vitamin B3 is a complex of three vitamins, namely, nicotinamide riboside (NR), nicotinamide (NAM), and nicotinic acid (NA), which are precursors of NAD+, a central catalyst of metabolism. NAD depletion is associated with poor immunity since cellular immune responses consume NAD.

Supplementation with B3 may thus boost both innate and adaptive immunity in COVID-19. NR appears to be the most suited for this purpose, with better pharmacological properties and a safety profile to match.

One recent trial showed that a combined nutritional supplement including NR with standard care shortened the recovery period in COVID-19 by a third, and larger studies are warranted with these findings.

SUMMARY: Vaccination appears to be the only safe and effective route to achieve durable and global immunity and end the pandemic. Other short-term preventive methods include behavioral changes and non-pharmaceutical interventions, including mask-wearing in public, social distancing and hand washing.

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