The main topic of discussion these days seems to be centered around coronavirus, or COVID-19. COVID-19 is a virus that has affected 1.86 million people so far in the U.S. alone and 6.56 million people worldwide. The more common symptoms of COVID-19 are cough, shortness of breath, fever, chills, muscle pain, sore throat, and new loss of taste or smell, but some cases lead to exacerbated versions of these symptoms. It’s commonly known that people that have the most severe cases of COVID-19 are typically those of older age or those with underlying medical conditions, but did you know that Vitamin D (VIT D) can lower the risk of severe cases of COVID-19?

Coronavirus (COVID-19) Facts and Stats

  • 38.9% of COVID-19 cases are people aged 18-44.
  • COVID-19 is closely related to SARS, which is why COVID-19 is also called SARS-CoV-2.
  • COVID-19 spreads person to person through droplets when someone coughs or sneezes.
  • 35% of COVID-19 patients are asymptomatic.
  • 23 companies are working on creating the first COVID-19 vaccine, which could be released as early as 2021 (which is extremely quick compared to the typical 10-15 year process that other vaccines have to go through!).

What is Vitamin D?

Before we get into the details of the relationship between Vitamin D and COVID-19, it’s vital to understand what VIT D does in our body and why it is so important. Vitamin D is a fat-soluble vitamin (which means it is not expelled through urine, and our body stores it in our cells) that helps to maintain healthy bones by helping our body absorb calcium, which helps build bones. Vitamin D also helps muscles move, while nerves use VIT D to send messages to other parts of the body. Even the immune system needs VIT D to fight off bacteria and viruses. Without Vitamin D, our bones would become brittle and could lead to conditions like osteoporosis.

Fuctions of Vitamin D Info

What foods have Vitamin D?

Vitamin D is found in fatty fish, such as salmon, tuna, and mackerel. Oily fish is the best source of Vitamin D, but Vitamin D is also found in mushrooms, cheese, and egg yolks. Although there aren’t many natural food sources of VIT D, many milk products, alternative milk products, orange juices, and yogurts are fortified with VIT D, which means that Vitamin D has been added to these products.

However, the sun can also be a source of Vitamin D! When skin is exposed to the sun, the body makes VIT D. Taking a walk during this quarantine season can be enjoyable and beneficial for your health!

Easy ways to get Vitamin D in your diet

There are many simple ways to incorporate Vitamin D rich foods into your diet. Here are a few ideas for each Vitamin D rich food that were mentioned above.

Fatty fish


  • Herb sauteed mushrooms
  • Mushroom barley soup
  • Grilled mushroom kebabs
  • Mushroom burgers
  • Grilled portobello “patties.”

Egg yolks

  • Omelet with mushrooms and ricotta
  • Egg breakfast sandwich with lettuce and tomato
  • Shakshuka
  • Vegetable frittata with herbs
  • Spinach and chickpeas with eggs
  • Cold soba noodles with eggs and peas

Egg meal with a full plate

Who is at risk of being Vitamin D deficient?

Some groups of people are at higher risk for Vitamin D deficiency. Some may find it challenging to incorporate Vitamin D rich foods into their diet, while some lack Vitamin D due to biological factors.

Breastfed infants

Breastfed infants cannot meet their Vitamin D needs through breast milk unless the mother supplements with high amounts of VIT D. This is why it is generally recommended by physicians that breastfeeding mothers take VIT D supplements or eat more Vitamin D rich foods.

Older adults

As we age, our ability to synthesize vitamin D efficiently diminishes. Also, older adults tend to spend more time indoors, which means less VIT D from the sun. This deficiency of VIT D contributes to the increased likelihood of bone pain and hip fractures for older populations.

People with limited sun exposure

People who are home for most of the day (which are many of our current situations due to quarantine and stay at home orders), as well as women who wear robes and cover their skin for religious reasons, often suffer from VIT D deficiencies. A simple fix to this issue is VIT D supplementation and consumption of VIT D rich foods.

People with darker skin tones

People with darker skin tones have more melanin in the epidermal layer of their skin. This reduces a person’s ability to produce Vitamin D from the sun. However, those of African American descent actually have reduced rates of bone fracture and osteoporosis compared to those of Caucasian descent. Therefore, skin tone does not seem to significantly impact Vitamin D levels enough to lead to adverse health consequences.

People with inflammatory bowel disease or other conditions that cause fat malabsorption

As mentioned earlier, Vitamin D is a fat-soluble vitamin. Conditions that cause fat malabsorption prevent the gut from absorbing dietary fat, which also means that VIT D is not absorbed correctly. Since those with conditions that cause fat malabsorption cannot successfully absorb VIT D, supplementation may be needed. Additionally, those with conditions that cause fat malabsorption may avoid foods that are high in VIT D if these foods exacerbate symptoms of their health.

People who have undergone gastric bypass surgery

Gastric bypass surgery is a surgery where a section of the small intestine is removed. When someone goes through gastric bypass surgery, they often experience vitamin deficiencies since the small intestine absorbs fat-soluble vitamins such as Vitamins A, D, E, and K.

People who live on the Northeast Coast

The Northeast is notorious for long winters that offer short windows of daylight. Colder temperatures also influence people to stay indoors, and in areas such as Massachusetts and Maine, people are inclined to stay in for most of the year. With little to no sun exposure for months on end, residents of the Northeast in the U.S. often find themselves lacking more VIT D compared to those who reside in sunnier states such as California, Texas, and Florida.

Symptoms of Vitamin D deficiency

There are many telltale signs of Vitamin D deficiency. Many people are Vitamin D deficient and are unaware of their lack. Since these symptoms are often thought to be caused by other issues such as stress from work or school, soreness after exercise, or the weather, it is essential to bring up these symptoms with your doctor. Your doctor can perform a blood test and confirm if you need VIT D supplements.

Signs you're Vitan D deficient

These signs include:

  • Feeling constantly tired or lacking energy.
  • Depression
  • Sleep issues
  • Anxiety
  • Weak or achy bones
  • Getting sick frequently
  • Inflammation or swelling

Fun facts about Vitamin D

  • Vitamin D is often called the “sunshine vitamin” because of our body’s unique ability to synthesize Vitamin D from the sun.
  • Even sunscreen with SPF 8 can block 98% of Vitamin D intake! Spending 10-15 minutes outside without sunscreen can be highly beneficial for Vitamin D synthesis, but make sure to apply some afterward.
  • Even if you live in a sunny state, you could be deficient in VIT D.
  • Vitamin D helps your body absorb calcium, so if you are VIT D deficient, you may not be absorbing enough calcium.
  • When mushrooms are exposed to ultraviolet light, they convert ergosterol into Vitamin D.


How Vitamin D impacts COVID-19 mortality and severity

A study conducted by researchers at Trinity College Dublin found that VIT D deficiency could be linked to COVID-19 mortality rates. When areas with high COVID-19 mortality rates were examined, they found that there was a common factor other than age and medical condition; these areas also had high rates of Vitamin D deficiency. Countries that had lower rates of Vitamin D deficiency also had lower rates of COVID-19 mortality. Some of these countries are located in Northern Europe, where their diets are rich in cod liver oil, VIT D fortified products, and VIT D supplements, which contribute to the lower rates of VIT D deficiency. An additional study conducted by Northwestern University showed similar results after analyzing data from various countries affected by COVID-19. Researchers that also examined the 1918 influenza pandemic found that healthy VIT D levels were linked to lowered mortality risk as well.

Vitamin D levels per country Versus Covid 19 mortalityVitamin D levels Per Country Versus Covid 19 cases graph

A more in-depth look behind the science of Vitamin D and COVID-19

Vitamin D deficiency is known to contribute to acute respiratory distress syndrome (ARDS), and many ARDS patients need a more extended period on a ventilator. Many COVID-19 patients meet the criteria for ARDS diagnosis: they have an acute syndrome, bilateral opacities on lung images, abnormalities in gas exchange, and their COVID-19 diagnosis is not explained by heart failure or volume overload. Not all COVID-19 cases meet the criteria, but once again, adequate VIT D intake can only help, not harm.

The Northwestern University study specifically takes a look at what is called a “cytokine storm,” which is when an immune response is “so aggressive that it causes cell death and increases susceptibility to acute respiratory tract infections.” VIT D has many protective factors when it comes to our bodies. VIT D influences immune system response and defense, which help prevent illnesses from the common cold to influenza.

Vitamin D: What’s the verdict?

Although VitaminD cannot prevent anyone from contracting COVID-19, it could be helpful against lowering the risk of severe symptoms and mortality of COVID-19. Additionally, this possible prevention of severe COVID-19 symptoms and dying as a result of COVID-19 could help with “flattening the curve.” “Flattening the curve” refers to keeping the number of COVID-19 cases low so that hospitals can continue to adequately meet the demands that are required to keep up COVID-19 care. This prevents hospitals from getting overwhelmed or unable to provide the best care for COVID-19 patients. By preventing severe COVID-19 symptoms and maintaining symptoms that are manageable at home, we can continue to “flatten the curve.” Keeping VIT D levels at a healthy range is also beneficial for bodily functions, so it may be a good idea to get in some sun every day and eat salmon once or twice a week. However, before reaching for Vitamin D supplements at your local grocery store or pharmacy, make sure to consult your doctor to see if there even is a need for supplementation, as overconsumption of VIT D, which is 4,000 IU, can also be harmful to your kidneys. The recommended daily intake is 600 IU, but the Endocrine Society has suggested levels up to 2,000 IU for adults.

Overall, it can’t hurt to keep Vitamin D levels at a healthy range, and it could also help to prevent severe symptoms of COVID-19 and even mortality as a result of COVID-19. However, it is not yet known whether or not Vitamin D can be used as a treatment, so if you are experiencing COVID-19 symptoms, please call your doctor if you have any concerns.

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