Introduction
Vitamin D is an important nutrient your body needs to build and keep
your bones strong, among other benefits. Sunlight is the main source -your skin absorbs the sun’s ultraviolet rays and turns them into Vitamin
D.
But many people are deficient, or don’t get enough. This is especially
true if you’re older, don’t eat healthy foods, or have a darker skin tone.
And those low levels may raise your risk of severe COVID-19 if infected.
Here’s what you need to know.
Vitamin D and COVID-19
While Vitamin D boosts your immune system and eases inflammation,
experts say more research is needed on its antiviral properties.
Several studies indicate that those with low vitamin D levels are at
increased risk of SARS-CoV-2 infection and have worse clinical outcomes
after infection.
And while high levels of vitamin D might lower your risk for severe COVID19 infection, there is no evidence that taking vitamin D supplements will
provide protection against infection or improve outcomes in patients
with COVID-19.
Can taking vitamin D protect against COVID-19?
Few studies have investigated the effect of vitamin D supplements or
vitamin D deficiency on the risk of contracting COVID-19.
Still, studies have shown that vitamin D deficiency may harm immune
function and increase your risk of developing respiratory illnesses.
Additionally, some studies have indicated that vitamin D supplements
can enhance immune response and protect against respiratory
infections overall.
A recent review that included 11,321 people from 14 countries
demonstrated that supplementing with vitamin D decreased the risk of
acute respiratory infections (ARI) in both those who had deficient and
adequate levels of vitamin D.
Overall, the study showed that vitamin D supplements reduced the risk
of developing at least one ARI by 12%. The protective effect was
strongest in those with low vitamin D levels .
Moreover, the review found that vitamin D supplements were most
effective at protecting against ARI when taken daily or weekly in small
doses and less effective when taken in larger, widely spaced doses .
Vitamin D supplements have also been shown to reduce mortality in
older adults, who are most at risk of developing respiratory illnesses like
COVID-19.
What’s more, vitamin D deficiency is known to enhance a process known
as the “cytokines storm”.
Cytokines are proteins that are an integral part of the immune system.
They can have both pro-inflammatory and anti-inflammatory effects and
play important roles, helping protect against infection and disease.
However, cytokines can also induce tissue damage under certain
circumstances.
Vitamin D deficiency has been associated with reduced immune function
and may enhance the cytokines storm.
As such, researchers postulate that a vitamin D deficiency may increase
the risk of severe COVID-19 complications, as well as that vitamin D
supplementation may reduce complications related to cytokine storms
and uncontrolled inflammation in people with COVID-19.
Currently, multiple clinical trials are investigating the effects of vitamin D
supplementation (at dosages up to 200,000 IU) in people with COVID-19 .
Although research in this area is ongoing, it’s important to understand
that taking supplemental vitamin D alone can’t protect you from
developing COVID-19.
However, being deficient in vitamin D may increase your susceptibility to
overall infection and disease by harming immune function.
This is especially worrisome given that many people are deficient in
vitamin D, especially older individuals who are most at risk of developing
serious COVID-19-related complications.
For these reasons, it’s a good idea to have your healthcare provider test
your vitamin D levels to determine whether you have a deficiency in this
important nutrient. This is particularly important during winter months.
Depending on your blood levels, supplementing with 1,000–4,000 IU of
vitamin D per day is typically sufficient for most people. However, those
with low blood levels will often require much higher doses to increase
their levels to an optimal range.
Though recommendations on what constitutes an optimal vitamin D
level vary, most experts agree that optimal vitamin D levels lie between
30–60 ng/mL (75–150 nmol/L) (24Trusted Source, 25Trusted Source).
The bottom line
Vitamin D plays many important roles in your body, including
promoting the health of your immune system.
Scientific research suggests that supplementing with vitamin D protect
against respiratory infections, especially among those who are
deficient in the vitamin.
Recent research indicates that sufficient vitamin D levels may help
people with COVID-19 avoid adverse outcomes.
Still, we don’t know whether taking vitamin D supplements reduces
your risk of developing COVID-19 as a result of contracting the
coronavirus.
Talk to your doctor about supplementing with vitamin D to enhance
your overall immune response.