Vitamin D is a fat-soluble nutrient that plays a crucial role in several vital bodily processes and functions. Vitamin D is especially pivotal for strengthening the immune system and supplementing with this vitamin may help you to lower the risk of getting COVID-19 and lessen the severity of illness if one gets the infection. Although vaccination is considered a phenomenal measure to contain the spread of the SARS-CoV-2 virus, a recent study has stated that vitamin D may help prevent contracting coronavirus and reduce the risk of adverse outcomes.

Also Read: 5 Food Sources Incredibly Abundant In Vitamin D For Overall Wellbeing-Infographic

Read through this article to know how vitamin D affects immune response and how supplementing with this vital nutrient may safeguard you against respiratory ailments.
Vitamin D and covid-19

Role of Vitamin D In Triggering Immune System

Vitamin D is essential for the proper functioning of the immune system, which is the body’s first line of defence against infection. Potent anti-inflammatory and immunoregulatory traits of vitamin D support the activation of the immune system defence mechanism.

Vitamin D is also actively involved in improving the function of immune cells, including T cells and macrophages that shield the body against harmful microbes and pathogens. Deficiency of vitamin D has been linked with higher susceptibility to infections, diseases and other immune-related disorders.

Low levels of vitamin D is associated with an increased risk of respiratory diseases such as tuberculosis, asthma, and chronic obstructive pulmonary disease (COPD), and respiratory infections. Furthermore, vitamin D deficiency has been linked to impaired lung function, which may affect the body’s ability to combat respiratory infections.

How Vitamin D Supplement Prevent COVID-19 ?

Few studies have examined the effect of supplementing vitamin D in reducing the risk of contracting the SARS-CoV-2 virus. A recent study has analysed the vitamin D level in 235 patients admitted in the hospital with COVID 19. In this study, around 51.5 % of patients above 40 years of age with adequate levels of vitamin D did not suffer from any adverse outcomes such as unconscious, hypoxia and death when compared to patients with vitamin D deficiency. Moreover, the study has also revealed that vitamin D deficiency may damage the immune response and increased the risk of developing a respiratory illness.

A meta-analysis that included 11,321 people from 14 countries demonstrated that supplementing with vitamin D decreased the risk of acute respiratory infections in both those who had deficient and adequate levels of vitamin D. The protective effect was highest in those with low levels of vitamin D.

Vitamin D supplements have also reduced mortality in older adults who are at high risk of developing respiratory ailments like COVID-19, stated another study. Vitamin D deficiency is known to trigger a process known as the cytokine storm. Cytokines are protein that is a key part of the immune system. They exhibit both pro-inflammatory and anti-inflammatory effects and play a vital role in protecting the system against infection and disease.

Also Read: COVID-19: What Is A Cytokine Storm And How It Hampers Internal Organs In The Body

A cytokine storm denotes the uncontrolled release of pro-inflammatory cytokines that occurs in response to an infection or other factors. Excessive release of cytokines leads to severe tissue damage and aggravates the progression and severity of the disease. Moreover, it is a major cause of multiple organ failure and acute respiratory syndrome (ARDS), and an important factor in the progression and severity of coronavirus. While vitamin D deficiency has been linked with reduced immune response and enhances cytokine storm.


Health care experts suggest that Vitamin D bolsters the immune system and helps combat infections and respiratory ailments such as COVID-19. You can get a healthy dose of vitamin D through exposure to sunlight. While some of the food sources that are an excellent source of vitamin D include salmon, fatty fish, egg yolks, mushrooms and fortified cereals, orange juice, oatmeal and soy milk and almond milk.

Additionally, you may also get your vitamin D levels tested to determine whether you are deficient in this vital nutrient. Supplementing 1000-4000 IU of vitamin D per day is typically ideal for most people, however, those with exceptionally low levels will require higher doses to increase their levels to an optimal range.


1. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data
BMJ 2017; 356 doi: (Published 15 February 2017)

2. Targeted 25-hydroxyvitamin D concentration measurements and vitamin D3 supplementation can have important patient and public health benefits
William B. Grant, Fatme Al Anouti & Meis Moukayed, European Journal of Clinical Nutrition volume 74, pages366–376 (2020)
Med Hypotheses. 2020 Jul; 140: 109767.

3. Vitamin D: A simpler alternative to tocilizumab for trial in COVID-19?
Published online 2020 Apr 23. doi: 10.1016/j.mehy.2020.109767, PMCID: PMC7177149