TORONTO -- Researchers in Edmonton are among several groups around the world looking into whether there’s any benefit of boosting vitamin D levels in a patient’s blood as a means of protecting them against COVID-19.

Dr. Aldo J. Montano-Loza, an associate professor at the University of Alberta, is preparing to launch a study of at least 70 Albertans who contracted COVID-19 to see if their vitamin D levels put them at risk of severe infection and whether boosting these levels will help their condition.

Randomized participants in the “high-dose” arm of the study will be given two high-concentration doses of the vitamin in the first week of the study and one such dose in each of the next two weeks. Subjects in the “low-dose” arm will be given a much smaller dose of vitamin D, but on a daily basis. The results will then be compared to a control group. 

“We think that actually this may help to reduce the risk of having worse presentations and even reduce the duration of the disease,” Montano-Loza told CTV News.

Montano-Loza expects to begin his research soon, but is just awaiting funding for the project. He also holds out hope of expanding the study of vitamin D deficiency across Canada.

There is some urgency to this work, as more studies point to a possible link between the so-called “sunshine vitamin” and the severity of the coronavirus infection. There has also been an increasing number of studies showing vitamin D is somehow linked to COVID-19.

In a study of COVID-19 patients in the intensive care unit in New Orleans, doctors found that 100 per cent of the sickest patients under the age of 75 were deficient in the vitamin, many of them to critical levels.

“We suspected that we would find a high proportion, but to find any population that's 100 per cent deficient is quite striking,” said Dr. Frank Lau, associate professor of clinical surgery at Louisiana State University. “It's definitely worth looking more into.”

Vitamin D is known to have a crucial role in regulating the immune system and inflammation. Some studies show people with low vitamin D have more severe symptoms of the virus, a higher risk of being admitted to the ICU and have an up to 12 times higher risk of dying from the virus.

“You see that it’s people of colour, it’s elderly people, it’s people with chronic diseases, it’s people in nursing homes, and what these people all have in common is that they have lower vitamin D levels,” said William B. Grant, director of the Sunlight, Nutrition, and Health Research Center (SUNARC) in San Francisco, Calif.

Meanwhile researchers in Ireland reviewed data showing COVID-19 infections and deaths are actually lower in countries where vitamin D is added to food or where supplements are widely encouraged.

“In the Nordic countries, such as Finland and Norway, where there is massive fortification or high intake of vitamin D or high intake of supplements, those countries had [sic] the lowest infection rates and lowest rates of mortality from COVID,” said Dr. Eamon Laird, research fellow at the Trinity College School of Medicine in Ireland.

This area of study is still in its early stages, however, and doctors don’t yet know whether there’s another factor at play here, so researchers around the world have turned totesting supplements of the vitamin in deficient COVID-19 patients to see if it helps.

“We still don't have evidence that supplementation is going to make a difference, but because of the first association, we definitely need more research,” he said.

Some scientists warn against the use of high-dose vitamin D supplements for COVID-19 treatment, however.

Researchers from the United Kingdom, Europe and the U.S.published a warning on Thursday in the journal BMJ Nutrition, Prevention & Health which states that while early research warrants further study, currently “there is no strong scientific evidence to show that very high intakes of vitamin D will be beneficial in preventing or treating COVID-19.”

“We strongly caution against doses higher than the upper limit and certainly of very high doses of vitamin D unless under personal medical advice/clinical advice by a qualified health professional,” the researchers wrote in the notice.

The report also notes there are several health risks associated with these supplements, including reduced kidney function.

However, if the new research shows there’s something to it, it could become a cheap, easy and virtually risk-free form of treatment, Lau said.

“If it turns out that it’s important, then we can make sure that everybody is appropriately supplemented or has appropriate vitamin D levels without a lot of risk to those patients,” he added. 


With experts warning of a potential second wave of COVID-19 to come in fall or sooner, and with no imminent vaccine, the timing of this research is crucial.

“Every measure that we can try to improve the condition of these patients will have a significant health and economic significance,” said Montano-Loza. “We need to explore any other possibility in parallel with drug development and vaccine development.”

Most studies anticipate finishing up in the fall, though one being done in France is aiming for completion in July.

Despite the positive signs, Montano-Loza is strongly recommending people do not ingest excessive amounts of vitamin D in attempt to protect themselves against the virus.

“The recommendation is to continue the normal supplementation according to current guidelines,” he said