Vitamin D: Do You Need It?

Vitamin D: What’s the big deal?

Health has been a popular topic in US news, and it’s not surprising as new technologies emerge allowing us to learn more than ever before about the human body and the way it functions. This year, health has been on everyone’s minds with the COVID-19 pandemic breeching borders and changing our lives. 

One emerging claim that’s been reported on in the media is a link between vitamin D deficiency and severity of COVID-19 cases. Reports are claiming that those deficient in vitamin D are not only at greater risk for contracting COVID-19, but also having a more severe case. One hospital in Spain found that out of 200 COVID-19 patients, over 80% had a vitamin D deficiency. A study from the University of Chicago Medicine found that those who are suspected to be vitamin D deficient have a greater risk of testing positive for COVID-19 than those who are not suspected to have a vitamin D deficiency.

Why is this the case? 

Vitamin D is best known for its role in bone health: it enhances calcium absorption in the human body and supports the production of new bone. However, vitamin D plays several different roles in the body, and one of those roles is within the immune system. Multiple studies, dating as far back as 1988, have found that people with lower vitamin D levels were more likely to experience upper respiratory tract infections than people with sufficient levels of vitamin D. So, these recent reports about vitamin D concerns are not new. Vitamin D has been shown to give an increased protection from infections. 

How do you know if you’re vitamin D deficient?

Vitamin D level testing is done through a blood sample, and is covered by most insurance. You can call your RDN or primary care provider to ask about their current options for vitamin D level testing. This is the only sure way to know if you have actual vitamin D deficiency. 

Generally speaking, if you spend time outdoors frequently, eat a well-balanced diet, and have no other health issues, you should have no concerns about your vitamin D levels. The main source of vitamin D is sun exposure, and dietary intake contributes as well.

If you want to boost your vitamin D intake to help protect against infections, here are some things you can add to your diet:

  1. Add saltwater fish to your diet.

One 3 ounce serving of sockeye salmon contains 74%-119% of the RDA of vitamin D. Other saltwater fish is also high in vitamin D, as well as healthy fats and protein. However, some of these fish, such as swordfish, contain higher levels of mercury. It’s important to talk to your RDN about the best choices for your personal diet, and about the frequency at which you should eat certain foods.

2. Add mushrooms to your diet.

Half a cup of grilled, portabella mushrooms contains 52% of the RDA of vitamin D. One cup of white mushrooms contains 46% of the RDA of vitamin D. Mushrooms are great additions to savory soups and vegetable stir frys.

3. Choose vitamin D fortified foods.

Many foods such as cow’s milk, cereals, orange juice, and almond milk have been fortified with vitamin D because of its important roles in the body. We always emphasize a diet centered around natural, whole foods, but there are benefits to some processed foods. Always be sure to talk to your RDN about how these foods can fit into your personal diet, to enhance your health and support your goals.

4. Take a vitamin D supplement.

The RDA for vitamin D is 600 IUs per day for adults, or 800 IUs for adults older than 70. Generally, taking a vitamin D supplement of 600 IUs, especially in the winter months, is a safe way to make sure you’re getting enough vitamin D to support bone health and immune function. The limit for vitamin D supplementation is 4,000 IUs per day. Consult your RDN to find the amount of vitamin D supplementation that’s right for you.

The main takeaway here is that vitamin D has important functions in the human body. It’s been shown in studies as far back as 1988 that vitamin D protects against infection, specifically against upper respiratory tract infections. Vitamin D can be acquired through direct sunlight exposure or through the diet. Over the counter vitamin D supplements are also available, and can be taken safely in amounts under 4,000 IUs per day. To protect yourself against infection, get outside, talk to your RDN about good dietary sources of vitamin D, and consider supplementation during winter months.

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