People with untreated vitamin D deficiency, measured as less than 20 nanograms per milliliter, may be almost twice as likely to contract COVID-19 compared to people who get sufficient doses of the sunshine vitamin, a small study published Thursday in JAMA Network Open finds.
The study, out of UChicago Medicine, looked at 489 people who were tested for COVID-19 and had gotten their vitamin D levels measured within the year.
The findings support past research linking low vitamin D levels with more severe coronavirus infections and a higher risk of death from the disease, though there's still no evidence that the vitamin can prevent or cure the disease.
"Vitamin D is important to the function of the immune system and vitamin D supplements have previously been shown to lower the risk of viral respiratory tract infections," lead author Dr. David Meltzer, chief of hospital medicine at UChicago Medicine, said in a press release. "Our statistical analysis suggests this may be true for the COVID-19 infection."
More research is needed, he and his team added, to better understand whether there's a cause-and-effect relationship between supplementing with vitamin D and lowering your risk for COVID-19.
Future findings could be especially beneficial to Black and Hispanic Americans, populations at greater risk for both vitamin D deficiency and severe COVID-19.
"Understanding whether treating Vitamin D deficiency changes COVID-19 risk could be of great importance locally, nationally and globally," Meltzer said in the release. "Vitamin D is inexpensive, generally very safe to take, and can be widely scaled."
Vitamin D is known to strengthen the body's ability to fight off viruses, but it's not a panacea and too much can be dangerous
How vitamin D affects coronavirus risk and severity has been of interest to researchers and health professionals since the beginning of the pandemic.
One study out of Italy last month found that after 10 days of hospitalization, about half of the 42 patients with severe vitamin D deficiencies died, while only 5% of patients with sufficient vitamin D levels died.
Other research from around the world has found that higher levels of vitamin D correlate with more mild illnesses, and that countries that have high levels of vitamin D also tend to have lower death rates from COVID-19.
The link makes sense because vitamin D is known to strengthen the body's ability to fight off viruses, and can help quell cytokine storms, or when the immune system overreacts to a viral invasion — something that affects many patients with severe COVID-19, Business Insider's Susie Neilson previously reported.
But other variables could be play; for instance, people who live in crowded housing or work long hours indoors doing essential jobs are both less likely to get sufficient vitamin D from sunlight and more likely to be exposed to COVID-19.
Still, getting sufficient — though not too much — vitamin D, either through sunlight, supplementation, or certain foods like fatty fish, is important not just for its potential protection against the coronavirus, but for overall health.
Deficiencies are also linked to heart disease, diabetes, immune system disorders, certain types of cancers, and bone problems like osteoporosis.
- Read more:
- Vitamin D may be a good defense against the coronavirus, according to several new reports. Here's what you need to know.
- Vitamin D deficiency may be tied to a higher risk of severe coronavirus infection
- Low vitamin D levels may be linked to a higher chance of dying from the coronavirus — here's how to avoid a deficiency
