How & Why To Get Vitamin D From Sources Other Than The Sun During COVID-19
Vitamin D is an essential nutrient, meaning that the body needs it to function smoothly but doesn't produce enough of it on its own. That's where the sun usually comes in: When UVB rays from sunlight hit the skin, it stimulates the production of vitamin D3 in the body, which supports immunity, helps us absorb calcium and phosphorus, and maintains healthy blood pressure. Those who are deficient in vitamin D run a higher risk of developing heart disease, autoimmune disease, and some cancers. (According to the NIH, anyone with less than 20 ng/mL vitamin D in the blood runs a risk of deficiency.)
It's pretty amazing to consider that the sun is responsible for setting off such a crucial process, and it's another reminder that humans and nature depend on one another to thrive. Unfortunately, this also means that a lot of people—even those of us who live in sunny climates—are deficient in vitamin D since as a society we tend to spend a lot of time indoors.
A 2011 poll estimated that 41.6% of Americans were deficient in the vitamin, with older people and those who have darker skin being at an even higher risk for a deficiency. Remember 2011? That was a year we could go outside without thinking twice about it! Now that so many of us are staying home for the sake of our health and the health of others, getting enough vitamin D has become even more of a challenge.
How (and why) to make sure you're getting enough vitamin D during COVID-19.
Unfortunately, riding out quarantine next to a sunny window won't help bring your vitamin D levels up, since UVB rays don't travel through glass. And while eating foods that contain vitamin D—such as eggs, white mushrooms, shrimp, and fortified dairy products—can help raise your levels, it's unlikely it will get you up to your daily quota of 400 to 800 IUs a day at least.
"Unless you're eating 30 ounces of wild salmon a day or downing 10 tablespoons of cod liver oil with breakfast, you might need to start taking a supplement to make sure you're getting optimal levels," functional medicine doctor Mark Hyman, M.D., writes on mindbodygreen, adding that he recommends a vitamin D supplement to nearly all of his patients.
It's worth noting that some recent studies have noted a correlation between vitamin D deficiency and coronavirus mortality. Most recently, a research team out of Northwestern University analyzed hospital data around the world and found that patients with vitamin D deficiency were twice as likely to experience severe complications from COVID-19. Another, published in the journal Aging Clinical and Experimental Research, looked into European countries specifically and found that those with populations who suffered higher rates of vitamin D deficiency also had higher rates of coronavirus fatality.
Both teams of researchers caution that their study designs were not perfect, though, and correlation does not necessarily mean causation. Previous research has found that vitamin D supplementation can negatively affect the body's ability to fight certain infections. (Here's a more thorough explainer on how vitamin D affects immunity.)
All this is to say that at this time, there is still no known cure for COVID-19, and the best methods of prevention are washing your hands, maintaining social distance, and avoiding touching your face.
The bottom line.
Our bodies need vitamin D to stay healthy, but a significant portion of the population is deficient in it. During times like these, when getting sunshine can be tricky depending on where you live, you might need to look elsewhere to fill your quota of this essential hormone.