Writer and producer Tyler Perry is by no means a health expert. But when he posted a video on Instagram in April discussing Black people, their likelihood of having low vitamin D levels, and the possible connection to Covid-19, it caught my attention. In the video, he said, “a lot of people who have died of Covid-19 were low in vitamin D.” And it turns out, one preliminary study from Northwestern University found a link between severe vitamin D deficiency and higher mortality rates.

I’ve always known that Black people were more likely to have low vitamin D levels, but I never gave it a second thought — until now. So naturally, as I was trying to determine whether or not I should pay attention to these levels and the purported risk association with Covid-19, I found myself spending my free time researching the topic and wondering if my family got enough sun or if we should be taking supplements.

Here’s what I found out.

Vitamin D doesn’t act like a typical vitamin. It’s an essential nutrient, which means the human body needs it but can’t make it on its own. While some foods such as salmon and dairy contain (or are fortified with) vitamin D, human beings get most of their vitamin D from the sun, through a chemical reaction in the skin that produces vitamin D. Black people have higher amounts of melanin in their skin than those with lighter skin tones, and melanin naturally provides some protection from the sun, but it also reduces the skin’s ability to produce vitamin D from sunlight. What’s more, many Black people are lactose intolerant, so their diet often lacks dairy fortified with vitamin D, leaving them with lower than average levels in their system.

According to a study conducted by the Cooper Institute, nearly 76% of African American adults are vitamin D deficient. And while it’s true that Black people commonly have lower levels of vitamin D, some studies suggest that commonly used tests might overdiagnose vitamin D deficiency in Black people.

“It’s thought that people who have vitamin D deficiency can’t fight off infection as strongly and have a weakened immune response, so it makes sense that they will have a higher instance of infection.”[…]