Sufficient blood vitamin D levels play an effective role in immune system functioning, which can contribute to a satisfactory cellular response and protect against the severity of infections caused by microorganisms. As a result, the pandemic provided an opportunity to highlight the role of vitamin D in supporting immune health.
The Council for Responsible Nutrition’s Vitamin D & Me! Education Initiative recently highlighted 13 meta-analyses that included over 3 million participants. Overall, the findings suggest that higher blood levels of vitamin D are correlated with lower incidence or severity of COVID-19 in most of the research.
“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,” said Luke Huber, ND, MBA, vice president of scientific and regulatory affairs at the Council for Responsible Nutrition (CRN).
The meta-analyses were generated from over 100 studies published since the onset of the pandemic. Most examined blood levels of vitamin D and COVID-19, while two exclusively examined vitamin D consumption in relationship to the illness.
Key takeaways
- Higher blood levels of vitamin D appear to be correlated with lower incidence of COVID-19 (in most but not all of the reviews)
- Severity of and mortality from COVID-19 was associated with lower vitamin D levels (in several but not all of the meta-analyses)
- One meta-analysis found reduced mortality with vitamin D intervention following COVID-19 diagnosis, while a smaller meta-analysis had the same finding (the smaller study did not reach statistical significance)
One of the strongest conclusions from one meta‐analysis indicated that odds of getting infected with SARS‐CoV‐2 increased by 3.3 times in individuals with vitamin D deficiency and the probability of developing severe stages of COVID‐19 is over 5 times higher in patients with vitamin D deficiency.
Other factors
While vitamin D levels appear to play a significant role in outcomes and severity, the studies also noted other risk factors for severe illness, such as older age, male gender, obesity, cardiovascular disease, chronic lung disease, diabetes and cancer. Additionally, several studies have shown that Black, Hispanic and Asians account for a disproportionately higher number of hospitalizations and deaths due to COVID-19 in the United Kingdom and the United States. Because factors such as age and race cannot be altered, researchers are hoping to zero in on modifiable factors that might contribute to COVID-19 severity such as vitamin D levels.
Dose still a question
While the overall consensus is that higher vitamin D levels are linked to lower COVID-19 rates and severity, the dosing is less certain as it varied widely across the studies. As several of these analyses pointed out, further research is needed to determine appropriate dose, duration, and mode of administration of vitamin D.
“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,” said Huber, “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.”
Source: The Council for Responsible Nutrition
Vitamin D & Me!