There has been a lot of discussion in the news and on the web about Vitamin D deficiency and COVID-19, so I wanted to look a little deeper into the science and data behind it.
One place to start is a widely cited article in the British Medical Journal in 2017, which was a meta analysis (a compilation of multiple randomized controlled trials) showing that Vitamin D supplementation had beneficial effects on preventing respiratory tract infection, particularly in people who are deficient.
There have also been a lot of articles and observational studies which have noticed a correlation between Vitamin D deficiency and severity of COVID-19 illness. A preprint article (one that is not yet peer-reviewed) from the University of Chicago concluded that vitamin D deficiency that is not sufficiently treated is associated with increased COVID-19 risk. An article in the Journal for the Society of Nutrition and Food Science explores possible explanations for the way Vitamin D deficiency may cause more severe response to COVID-19.
So does that mean stocking up on Vitamin D will protect you from COVID-19?
Not necessarily. People with vitamin D deficiency are more likely to have other chronic illnesses that can put them at increased risk for severe COVID-19 infection, which can confound the results. These studies also focus on patients who are Vitamin D deficient and aren't necessarily evaluating the benefit in patients who already have normal Vitamin D levels.
So what should I do?
There isn't yet enough data to show that Vitamin D needs to be taken to prevent or treat COVID 19 infection; however, there may be a connection between deficiency and severity of infection. More scientific studies are needed to explore this connection.
Vitamin D deficiency is a common issue in the general population with a reported prevalence of up to 46%. People with lactose intolerance or gastrointestinal issues and people with limited sunlight exposure are some of the few at higher risk for deficiency. People of color are also at higher risk for deficiency; in fact, my husband and I were both found to have Vitamin D deficiency a few years ago and took supplements to correct our levels. Vitamin D deficiency can also cause problems with bone health, increase your risk for cardiac disease, and cause chronic fatigue. If you are in a high risk group for deficiency, consider discussing your Vitamin D level with your primary care physician and starting supplementation under their direction to get you back to normal levels.
Some physicians and dietitians may also recommend starting supplementation without checking your levels, and taking 1000IU per day is generally safe in most people (I highly recommend discussing this with a medical professional before starting supplements. Over-supplementation, usually when taking over 4000 IU per day, can lead to Vitamin D toxicity).
Most people can achieve their daily recommended Vitamin D intake through sun exposure and diet alone. The daily recommended dietary allowance is 400-800 IU.
Natural dietary sources of Vitamin D:
Fatty fish (salmon, cod, trout, sardines)
Foods which are commonly fortified with Vitamin D (Vitamin D is added):
Fortified Milk (most dairy milks as well as many non-dairy milks)
Many daily multivitamins can also safely provide the daily recommended allowance (look for it on the nutrition label).
For more information about Vitamin D and supplementation, keep following our blog and consider booking an information session today!