Can vitamin D help with symptoms of COVID-19? Possibly, it’s key to helping your immune system function.

Research shows vitamin D helps prevent acute respiratory distress syndrome, (ARDS), a common killer in COVID-19 patients

on’t add vitamin D supplements to your online checkout cart just yet, it’s important to know if you are vitamin D deficient.

Although vitamin D is called a vitamin, it’s actually more of a hormone. When ultraviolet rays from sunlight strike your skin, the rays trigger vitamin D synthesis. You can also build up your vitamin D levels through certain foods.

Higher-risk individuals who might consider supplements:

• People with darker skin pigmentation. They have more melanin, which reduces the body’s ability to produce vitamin D.

• Older people whose skin is less efficient at absorbing vitamin D.

• Those who spend most time indoors.

How vitamin D helps your immune system fight infections

It’s been known for years that vitamin D is essential for maintaining healthy bones and teeth but it also plays an important role in helping our immune system function. Low levels can lead to autoimmunity — when your immune system attacks your healthy cells — and increase your chance of infection.

The immune system is like an army that prevents invaders, such as viruses and bacteria, from taking over the homeland — your body.

Let’s say, for example, a virus is present in a patient’s lungs, specifically in the air sacs (alveoli) which could lead to acute respiratory distress syndrome (ARDS).

The innate immune system would be the body’s first line of defense. It activates macrophages, neutrophils and other cells to attack and destroy the outsider.

Natural killer cells and macrophages along with other immune cells recognize, engulf and destroy pathogens. The main purpose of these cells is to immediately prevent the spread and movement of harmful substances throughout the body. They are akin to soldiers shooting indiscriminately all over the enemy’s camp.

The second line of defense against pathogens is called adaptive immune response. The cells of the adaptive immune system are B cells and T cells. They produce antibodies that protect your body from a specific invader. They are like high-ranking officers that conduct specific missions targeting only certain enemies.

Cells of the adaptive immune system release cytokines, small proteins that attract more immune cells to the region, resulting in localized inflammation.

How acute respiratory distress syndrome kills COVID-19 patients

When activated immune cells surge into the lungs as a result of a cytokine storm, the lungs can become inflamed. Fluid from the smallest blood vessels leaks into the tiny air sacs, resulting in acute respiratory distress syndrome (ARDS). The fluid prevents the lungs from filling with enough oxygen, so less reaches the bloodstream, causing organs to fail.

Many COVID-19-infected patients are known to develop ARDS. According to a study published in The Lancet in March, researchers in China examined risk factors for 191 coronavirus patients who died while being treated in two hospitals in Wuhan, China. The study showed 50 of the 54 patients who died had developed ARDS; only nine of the 137 survivors developed ARDS.

A 2015 study published in Thorax showed that patients with ARDS and those at risk of developing it had vitamin D deficiency. The same study demonstrated that vitamin D can reduce damage to capillaries that connect the alveoli to larger blood vessels that may prevent ARDS.

In September 2017, Molecular Medicine Reports published a study that showed vitamin D had a protective effect on the lungs.

Possible link between vitamin D deficiency and COVID-19

The research is conflicting. According to a preprint study co-written by Vadim Backman, professor of biomedical engineering at Northwestern University, countries with low average vitamin D blood levels in the population had higher numbers of COVID-19 cases and deaths. However, another study from the United Kingdom National Health Service looked at the nearly 450 patients diagnosed with COVID-19 and did not find a link between vitamin D concentrations and risk of COVID-19 infection.

Worldwide, an estimated 1 billion people have inadequate levels of vitamin D in their blood and insufficiency affects almost 50% of the population. Most commonly, low levels of vitamin D are caused by insufficient exposure to sunlight.