Vitamin D sales up during pandemic
UNKNOWN so far if it CAN Prevent or treat Covid
Interest in vitamin D has spiked during the pandemic as people seek ways to improve their immunity. According to Nielsen data from December, sales for vitamin D increased 41.5 per cent year over year.
But while research suggests a possible connection between vitamin D deficiencies and COVID-19, experts say there isn’t sufficient evidence to support taking supplements to prevent or treat the disease.
“We don’t want to come to premature conclusions or kind of pin our hopes on the wrong mechanism,” said Hana Akselrod, an infectious-disease physician at George Washington University.
Vitamin D deficiencies are “not rare,” said Sabyasachi Sen, professor of medicine at GWU. According to the National Institutes of Health, groups that may not be getting enough vitamin D include older adults, people who are obese and those with darker skin — populations that have been disproportionately impacted by the coronavirus.
Vitamin D is believed to enhance the function of cells, such as T cells, that protect the body from pathogens and may help modulate inflammatory responses if the body is under attack.
“Now, what is unknown is whether it’s a cause and effect rather than an association,” Sen said.
Studies conducted in several countries have found correlations between vitamin D deficiencies and both coronavirus infections and more severe symptoms requiring hospitalization.
A study of 489 people in Chicago found that patients who had a vitamin D deficiency in the year before they were tested for COVID were 77-per-cent more likely to test positive than those with normal levels.
Similarly, a peer-reviewed study in Italy of a small group of patients who were hospitalized with acute respiratory failure due to COVID found that 81 per cent were vitamin D deficient. Researchers noted that patients with severe deficiencies “had a significantly higher mortality risk.”
“People who have lower blood levels of vitamin D tend to have a higher risk of being infected with COVID and having severe COVID illness,” said Joann Manson, a professor at Harvard Medical School. “But as we say in epidemiology, ‘Correlation doesn’t prove causation.’”
People with vitamin D deficiency often have other factors that could impact their chances of contracting the coronavirus and falling seriously ill, said Natasha Chida, assistant professor of medicine at Johns Hopkins University. Chida added that vitamin D levels typically drop when people are sick with diseases such as COVID.
There is also no solid evidence that vitamin D supplementation will lower the risk of becoming infected or developing a serious case.
Research into whether vitamin D is beneficial for COVID patients has returned mixed results. A small randomized study involving 76 patients hospitalized with COVID in Spain reported that calcifediol, an activated form of vitamin D that is different from overthe-counter supplements, appeared to reduce the disease’s severity.
But a double-blind randomized trial in Brazil with 240 participants found that one large dose of vitamin D did not shorten hospital stays or mortality rates among patients with severe COVID infections.
“There is some biologic plausibility that there could be some benefit,” Chida said. “It’s just that there still hasn’t really been a clear, slam-dunk answer that there’s benefit.”
Chida and other experts, however, are hopeful that an answer may be forthcoming. About 70 clinical trials focused on vitamin D and COVID are underway.
Manson said she recently launched a trial to evaluate whether high-dose vitamin D reduces the severity of illness in people newly diagnosed with COVID and whether it can prevent infection in their household members.
David Meltzer is working on two trials in Chicago to see whether vitamin D can lower the risk of COVID.
“Whether taking more vitamin D would lead to a decrease in the risk, I think there are lots of good reasons to believe that that’s possible,” said Meltzer of the University of Chicago. “But we don’t have the randomized trials yet to prove it.”
In the meantime, experts encourage people who know they are vitamin D deficient to continue treatment. For those considering starting to take supplements, first talk to a health-care provider.
The recommended daily allowance of vitamin D for most adults is 600 international units (IU), or 800 IU for those 71 and older. People should not take more than 4,000 IU per day. Going over could lead to side effects, including a higher level of calcium in the blood, which may cause kidney stones, among other problems.
People can improve their daily intake through diet and regular outdoor activity, experts said. Certain foods such as fatty fish or fortified dairy products and cereals can be good sources of vitamin D, Manson said. Getting outside for 15 or 20 minutes a day could also be helpful for vitamin D levels and overall health, Akselrod added.
“There are all of the positive confluences around nutrition and outdoor exercise that aren’t just limited to how many units of vitamin D you get every day,” Akselrod said.
“On top of that, people absolutely need to continue all the other safety precautions like masking and safe distancing and avoiding gatherings because we’re in the most dangerous phase of the pandemic yet.”
still hasn’t really Been a Clear, slam-dunk answer.