Vitamin D is a family of fat-soluble vitamins naturally present in many foods. Some people call it the “sunshine vitamin” because the body produces this compound when the skin is exposed directly to the sun. Humans typically consume two types of vitamin D: D2 and D3. Vitamin D3 comes from animal-sourced foods and D2 is man-made, for the most part. Both types are available as over-the-counter supplements, but studies suggest that vitamin D3 might be better for improving vitamin D levels.
Recent research has shown that taking vitamin D supplements reduces the risk of developing certain respiratory infections, like the influenza virus. Other studies have shown that vitamin D may protect against some types of cancer, including colon and breast cancer. Now, and in light of the COVID-19 pandemic, investigators want to know whether vitamin D could also reduce the risk of contracting the coronavirus.
Vitamin D and Immunity
Vitamin D is the master key to our immune health.
The immune system is a network of cells, tissue, and organs that defend the body against harmful invaders, like viruses and bacteria. Consuming certain nutrients can help you maintain a strong immune system. On the other hand, smoking, being obese or overweight, not getting adequate sleep, and taking certain medications may lead to a weak immune system.
Vitamin D plays many vital roles in the body, immune system support being one of the most important. Every cell in your body has a vitamin D receptor in the nucleus. Approximately 2,000 genes in our body (5% of our genome) are controlled by vitamin D.
According to a 2015 systematic review and analysis of past studies, vitamin D may protect against acute respiratory tract infections. The analysis, published by the British Medical Journal, looked at 25 clinical trials to better understand the relationship between vitamin D and immunity. Specifically, the authors wanted total to see if vitamin D supplements could potentially prevent respiratory infections.
The results showed that vitamin D supplementation reduced the risk of contracting at least one respiratory infection. Additionally, vitamin D was particularly effective at preventing respiratory infections among those who already had a deficiency.
Other reviews of the existing literature have found similar results, like this 2018 meta-analysis, which concluded that vitamin D supplements may have a protective effect against the influenza virus. However, some of the studies analyzed yielded no relevant results or showed no effects on the immune system.
But despite being so crucial for overall health and immunity, vitamin D deficiency remains an important public health issue. About 1 billion people have vitamin D deficiency worldwide, and nearly 50 percent of the entire world’s population has vitamin D insufficiency. In the United States, it is estimated that almost 40 percent of Americans are vitamin D deficient. Vitamin D deficiency is common among dark-skinned individuals, older adults, people who are obese and overweight, and hospitalized patients.
Currently, there is not enough information to say whether vitamin D3 is better for the immune system than vitamin D2.
Vitamin D and COVID-19: The best mask is a strong immune system!
A recent 2021 study shows how vitamin D could halt lung inflammation in COVID-19. The scientists discovered that in normal infections, Th1 cells, which are a subset of helper T cells that fights microbes within the cell, go through a pro-inflammatory phase. During this phase, the body clears the infection. Shortly after, the system shuts down to move onto the anti-inflammatory phase. The scientists discovered that vitamin D is key in speeding up this transition.
Vitamin D had previously been shown to have protective effects against respiratory viruses like the flu, and recent analyses demonstrate that the same could be true for COVID-19. If your level of vitamin D is at least 50 ng/ml (normal range is 20-100) you can not develop a “cytokine storm” (that which kills in Covid). Maintaining mid-levels of vitamin D in your system is crucial, however, 70% of the world is vitamin D deficient. Unfortunately, most insurance companies in America won’t pay for a vitamin D blood test to check D levels. 80% of Americans are also magnesium deficient (due to our mineral-depleted soils for growing food). Magnesium is a critical co-factor for D function.
One study led by Northwestern University researchers compared COVID-19 data from 10 countries to each country’s average vitamin D deficiency rates. They found that countries with more vitamin D deficiency had higher mortality rates, whereas countries with higher vitamin D levels were not affected as severely by the virus.
Several observational studies conducted at South Asian hospitals show that the prevalence of vitamin D deficiency was significantly higher among patients with severe coronavirus cases. An analysis of 489 patient records from the University of Chicago found that people who had vitamin D deficiencies before the pandemic were substantially more likely to receive a positive COVID-19 diagnosis than people with normal levels.
Further, according to a population-based study conducted in Israel, low plasma vitamin D levels increased the likelihood of COVID-19 infection even after adjusting for age and other demographic factors. Finally, a recently published Boston University study revealed that those who are vitamin D deficient have a 54 percent higher risk of getting infected with COVID-19.
Vitamin D had been previously shown to protect against respiratory viruses like influenza, and recent analyses demonstrate that the same could be true for COVID-19.
How much vitamin D should I take?
According to the National Institutes of Health (NIH), the recommended daily amount of vitamin D is 400 international units (IU) for babies up to 12 months, 600 IU for healthy individuals 1 to 70, and 800 IU for those older than 70 years. However, these daily intakes vary depending on several factors, including how much sun a person is exposed to, their diet, and whether they have a preexisting medical condition.
Now may be a good time to get your vitamin D levels checked if you haven’t done so already. The normal range of vitamin D is measured in nanograms per milliliter (ng/ml), and experts recommend aspiring for a vitamin D concentration of no less than 40 ng/ml.
Vitamin D deficiency is very common and may not always produce any signs or symptoms, but the good news is that it’s easy to fix. Increasing your sun exposure; eating more vitamin D-rich foods like salmon, egg yolks, mushrooms, or fortified foods; and taking a supplement are all effective ways of boosting your vitamin D intake.
Remember that no vitamin alone, even vitamin D, boosts the immune system without help from other good health habits. If the COVID-19 pandemic has got you researching how to strengthen the immune system, consider implementing these basic but powerful healthy-living strategies:
- Don’t smoke
- Wash your hands frequently
- Maintain a healthy weight
- Eat a diet rich in fruits and vegetables
- Get enough sleep
- Stay up to date with recommended vaccines
- Exercise regularly
- Build strong social connections
- Stay positive!
Cold and Flu Season is Really Low Vitamin D Season!
Everyone should supplement with vitamin D during what is known as “Cold and Flu Season”. It is believed most people get sick from illness and viruses due to the drop in vitamin D levels this time of year. You do not get as much sun exposure in the fall and winter and become immuno-suppressed due to vitamin D levels dropping drastically. It is important to note that if you live in the northern states, during fall and winter you’re probably getting zero vitamin D from the sun. Without the protection of vitamin D, you are open to contracting illnesses. Protect yourself and supplement with vitamin D!
