- A new study that looked at 216 people with COVID-19 found that 80 percent didn’t have adequate levels of vitamin D in their blood.
- The study also found that people who had both COVID-19 and lower vitamin D levels also had a higher number of inflammatory markers such as ferritin and D-dimer, which have been linked to poor COVID-19 outcomes.
- A different study found that COVID-19 patients who had adequate vitamin D levels had a 51.5 percent lower risk of dying from the disease and a significant reduced risk for complications.
- Medical experts theorize that maintaining adequate vitamin D levels may help lower risk or aid recovery from severe COVID-19 for some people, though more testing is needed.
All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub and follow our live updates page for the most recent information on the COVID-19 pandemic.
As part of the new study in the Journal of Clinical Endocrinology & Metabolism, researchers looked at 216 COVID-19 patients in a hospital in Spain. The scientists matched the patients to controls from another dataset.
Of all the patients, 82.2 percent were deficient in vitamin D.
In the research, men had lower vitamin D levels compared to women.
People who had COVID-19 and lower vitamin D levels also had higher inflammatory markers such as ferritin and D-dimer. Those have been
People with vitamin D deficiency had a higher prevalence of hypertension and cardiovascular disease. They also had longer hospital stays for COVID-19, the study showed.
Comorbidities such as hypertension, diabetes, and obesity are associated with low vitamin D status, said Dr. Hans Konrad Biesalski, a professor at the University of Hohenheim who has evaluated vitamin D and COVID-19.
“It looks like patients with a poor vitamin D status may have more severe COVID-19,” he told Healthline. But the new study didn’t find that relationship.
Nevertheless, in addition to the correlation between vitamin D levels and COVID-19 risk, many people are looking at how it may protect people or help them recover from the disease.
“One approach is to identify and treat vitamin D deficiency, especially in high-risk individuals such as the elderly, patients with comorbidities, and nursing home residents, who are the main target population for the COVID-19,” said study co-author José L. Hernández, PhD, of the University of Cantabria in Santander, Spain.
He said people at high risk for COVID-19 — older adults, those with underlying conditions, and people in nursing homes — can be treated with vitamin D.
“Vitamin D treatment should be recommended in COVID-19 patients with low levels of vitamin D circulating in the blood since this approach might have beneficial effects in both the musculoskeletal and the immune system,” Hernández said in a statement.
Should you have your vitamin D levels checked? Is taking a supplement enough to protect yourself, or at least to lower your chance of getting COVID-19?
Dr. Michael F. Holick, who has researched vitamin D and leads the Bone Health Care Clinic at Boston University, said that Endocrine Society Practice Guidelines don’t recommend everyone should be screened.
It’s reasonable to keep tabs on vitamin D levels in those with fat malabsorption syndrome, people with obesity, or those who have other medical issues, Holick told Healthline.
The Endocrine Society recommends that infants should get anywhere from 400–1,000 IUs daily, children 600–1,000 IUs daily, and adults 600–2,000 IUs daily. The amount needed depends on your current levels or if you’re trying to raise them.
Adults with obesity may need 2 to 3 times more, Holick noted.
If vitamin D status is low, supplementation may be helpful, Biesalski agreed.
There are several publications that have suggested that vitamin D deficiency is associated with increased risk for upper respiratory tract infections including influenza and the coronavirus, Holick explained.
“This was observed in all 50 states and for all ethnicities,” Holick said.
For people with COVID-19, Holick said there are no downsides to increasing your vitamin D intake unless a person has a rare disorder such as sarcoidosis and other granulomatous disorders.
Based on the literature and his own experience, it’s reasonable for children and adults to take an adequate amount of vitamin D as recommended by the Endocrine Society to help reduce risk for acquiring the virus, as well as reducing morbidity and mortality if a child or adult develops COVID-19, he said.
We don’t know that vitamin D has a preventive effect on the body, noted Dr. Steven Abrams, a pediatrics professor at the University of Texas at Austin.
“Very low vitamin D status has lots of negative consequences and this could be the case for COVID-19, but that’s not the same as saying that routine vitamin D supplementation will prevent severe infection,” he told Healthline.
More research is needed to better understand the link between vitamin D and COVID-19.
There’s already evidence that getting enough vitamin D regulates the immune system for optimal health. Holick said it would be interesting to know if taking vitamin D with the vaccine would improve the vaccine’s effectiveness.
Biesalski would like to know how a balance of vitamin A and D would impact the success of the vaccine, as has been shown for influenza and measles, he said.