Higher vitamin D status linked with better COVID-19 outcomes, reveals CRN

04 Nov 2021 --- Mounting research correlates higher vitamin D blood levels to lower incidences or severity of COVID-19, according to the Council for Responsible Nutrition (CRN). The US-based non-profit applauds the “significant link” found in most – but not all – of 13 meta-analyses from over 100 clinical trials specifically studying the vitamin and COVID-19.

“This growing body of research does not indicate that vitamin D is a substitute for vaccines, mask wearing, social distancing or other behaviors to mitigate the spread of the coronavirus,” says Luke Huber, vice president of scientific and regulatory affairs at CRN. 

“But the data does suggest that vitamin D levels may play a role, in combination with other therapies, in strengthening the immune system to resist the virus.” 

Vitamin D has support from EFSA for an immunity claim.Digging into the data 
Of the 13 meta-analyses CRN cites, most examined blood levels of vitamin D and COVID-19 while two exclusively examined vitamin D consumption in relationship to the illness. 

“We have known for years that vitamin D plays an important role in immune health, and now there are multiple meta-analyses that appear to demonstrate the benefits of this nutrient in COVID-19,” affirms Huber. 

Most of the reviews found higher blood levels of vitamin D appear to be correlated with a lower incidence of COVID-19. 

Several – but not all meta-analyses – found greater severity of and mortality from COVID-19 were associated with lower vitamin D levels. 

One meta-analysis found reduced mortality with vitamin D intervention following COVID-19 diagnosis, while a smaller meta-analysis did not see a statistically significant relationship. 

Timing and dosage of the interventions may have played a role in the differing results. 

Varying perspectives
Throughout the COVID-19 pandemic, experts have expressed mixed opinions on advising vitamin D supplementation. This is in light of some studies showing no correlation between the “sunshine vitamin” and the disease, as well as fears of too high doses. 

Nevertheless, England offered free vitamin D supplements last winter to more than 2.5 million people deemed vulnerable to COVID-19. In addition, a US-based campaign called #VitaminDforAll called for immediate widespread increased vitamin D intake. 

Timing and dosage of the interventions may play a role in differing meta-analysis results.In February, a US representative introduced a House resolution recognizing the potential role vitamin D may play in decreasing the severity of COVID-19. 

Mechanism for action?
While it is unknown how vitamin D may reduce severe COVID-19 outcomes, scientists have proposed certain theories. 

CRN notes that adequate vitamin D levels as well as a healthy balanced diet, particularly the Mediterranean Diet, have been identified as beneficial to offset this inflammatory response. 

Reduced inflammation could, in turn, ease the “cytokine storm,” which is when an infection triggers the immune system to flood the bloodstream with inflammatory proteins called cytokines. 

This cascade of inflammatory reactions can kill tissue and damage organs. It plays a critical role in COVID-19 patient outcomes, supports the non-profit. 

Additionally, vitamin D may exhibit antiviral effects by interfering with viral replication and, through its ability to stimulate the immune system and reduce inflammation. 

Vitamin D has also been explored in combination with other supplements, such as probiotics, for an enhanced ability to fight COVID-19. 

A portal for uncovering facts
CRN presented these latest findings via its Vitamin D & Me! initiative, a space for consumers to explore the collective research on this topic and to hear directly from the researchers involved. 

The initiative has tracked and reported research on the link between vitamin D and COVID-19 since May 2021. 

Brian Wommack, executive director of the CRN Foundation, adds: “Consumers need science-based evidence to make informed health decisions.”

By Missy Green