Vitamin D May Not Prevent COVID-19 Risk

Vitamin D May Not Prevent COVID-19 Risk

A New Study Says Vitamin D Supplement May Not Prevent COVID-19 Risk

A study made by Bonnie Patchen, a Ph.D. student at Cornell University finding the link between vitamin D and COVID-19. In her findings of the new study are similar to what she and her colleagues found with their research, which was published May 4 in the journal BMJ Nutrition, Prevention & Health. Patchen said that in their research, she and her colleagues looked at how well the genetic variants predicted vitamin D levels across different populations. Their results were consistent for people of European ancestry, she said, even when taking into account other factors that can affect vitamin D levels such as body mass index (BMI) and older age. But the associations were less consistent in African ancestry individuals. Patchen said the level of variation is similar to a change that might be seen with taking a low-level supplement, around 400 to 600 International Units (IU) of vitamin D. But it doesn’t necessarily address the kind of acute changes in vitamin D levels that you might get with a high-dose treatment, Patchen explained. In another study, which was published on June 1 in the journal PLOS Medicine researchers at McGill University in Canada focused on genetic variants that are linked to increased vitamin D levels. People whose DNA contains one of these variants are more likely to naturally have higher levels of vitamin D, although diet and other environmental factors can still affect those levels. 

This type of analysis called Mendelian randomization study is like a genetic simulation of a randomized controlled trial, the “gold standard” for clinical research. Researchers found that people who have one of these variants - who are more likely to have higher vitamin D levels didn’t have a lower risk for coronavirus infection, hospitalization, or severe illness due to COVID-19.

Dr. Martin Kohlmeier, a professor of nutrition in the Gillings School of Global Public Health at the University of North Carolina, said “If you feed somebody a vitamin D supplement, it doesn’t matter how much you change the bound amount, it’s how much you change the free amount that matters for innate immunity.” The problem, he explained, is that the genetic variants used in Mendelian randomization studies of vitamin D are mainly related to the gene-binding protein for vitamin D.

Another study that was published February 17 in the journal JAMA, was carried out in Brazil. Where doctors gave patients COVID-19 patients a single oral dose of 200,000 IU of vitamin D, which is a very high dose, one that should only be taken under medical supervision or an inactive placebo. Researchers found that the large dose of vitamin D had no effect on patients’ length of stay in the hospital.

Dr. David Meltzer, a professor of medicine at The University of Chicago Medicine and his colleagues did their own analysis of the data from this study. They found that for people with low vitamin D levels, there was no effect of vitamin D levels on COVID-19 outcome. But it was a different story for people who entered the hospital with higher levels. The people with high vitamin D who were given additional vitamin D actually did better. 

Like Kohlmeier, Meltzer thinks it’s important to test the effect of vitamin D supplementation on COVID-19 risk, rather than just look at the levels in the blood. The vitamin D intake that you have on a daily basis or the amount you produce through sun exposure probably matters to some degree, he said, independently of your blood levels.

The results from these studies, which may not be available until later this year may provide a better idea of whether vitamin D can prevent respiratorily infections such as COVID-19.