Vitamin D may not be effective in protecting against COVID-19

New research published in PLOS medicine Genetic evidence suggests that it does not support vitamin D as a protective measure against COVID-19.

Vitamin D and COVID-19. Image Credit: Alrandir / Shutterstock.com

No evidence of high vitamin D benefits over COVID-19

The ability of vitamin D to protect against COVID-19 is a valuable concern for public health, but supporting evidence is limited. Previous studies using observational data suggest that increased vitamin D levels may protect against COVID-19. However, these findings proved to be inconclusive and perhaps confounding, due to limited consideration of genetic factors.

However, the results of McGill University-based researchers in Quebec, Canada, including Guillaume Butler Laport and Tomoko Nakanishi, show that the link between vitamin D production and COVID-19 protection is uncertain.

The team conducted a Mendel randomization study using genetic variation strongly associated with increased vitamin D production to assess the relationship between vitamin D levels and COVID-19 susceptibility and severity. Genetic data were collected from 4,134 people with COVID-19 and 1,284,876 people without COVID-19 from 11 countries.

The analysis aims to determine whether a genetic predisposition to higher vitamin D levels is associated with less severe disease outcomes in COVID-19 patients. Such a relationship would prove a link between vitamin D levels and disease resilience.

The results of the analysis revealed that there was no association between genetically determined vitamin D levels and the outcome of COVID-19 infection. Indeed, individuals made no difference in susceptibility, hospitalization, or severe illness.

Such findings suggest that a genetic predisposition to higher vitamin D production or additional vitamin D supplementation with dietary supplements may not improve COVID-19 results in the general population.

Vitamin D supplementation as a public health measure to improve results is not supported in this study. Most importantly, our results suggest that investment in other therapeutic or prophylactic measures should be prioritized in COVID-19 randomized clinical trials.

Dr. Butler Laporte

Uncertainty Factors and Future Studies

Due to the nature of data collection and analysis, this study has certain limitations.

For example, this study did not include individuals who were deficient in vitamin D production. This may represent some of the individuals who may benefit from the supplement. This may be an additional factor to include in future research. Further factors may include countries with relatively low dietary vitamin D levels. It may benefit from additional supplements as well as individuals who are deficient.

These characteristics demonstrate the complexity of studying vitamin-related effects. Dr. Butler Laporte said: “Most vitamin D studies are very difficult to interpret because they cannot adjust for known risk factors for severe Covid-19 (aging, institutionalization, chronic disease, etc.), which are also predictors of low vitamin D. The best way to answer the question of the effects of vitamin D is through randomized trials, but these are complex, resource-intensive, and take a long time during the pandemic.

In addition, genetic variation was obtained only from individuals of European ancestry, so future studies will be needed to determine the relationship with COVID-19 results in other offspring populations. It may also be useful to use other methods of randomization or procedural techniques.

Mendel randomization can reduce potential bias from related risk factors such as institutionalization and chronic disease, thus providing clearer insights into the role of risk factors such as vitamin D.

In the past, Mendel randomization has consistently predicted the results of large, costly, and timely vitamin D trials. Here, this method does not provide clear evidence that vitamin D supplementation has a significant impact on COVID-19 results. “

Dr. Butler Laporte

Inclusion of complexity factors such as additional countries, dietary composition, and descent may further elucidate the potential association between vitamin D levels and the severity of COVID-19. Research benefits from integrating more complex ones, limiting the propagation and impact of the COVID-19 pandemic, but other potential solutions should be prioritized.