Two good studies on vitamin D levels and SARS-CoV-2 have been published recently in major journals. Both studies back up all the previous research on vitamin D and immune function.
This isn’t really new news… Having adequate vitamin D levels is vital for good immune function – whether for COVID-19, the flu, other respiratory viruses, Dengue fever, etc.
This latest vitamin D study included 191000 participants and used ‘deidentified’ test results from Quest. The participants had all had a vitamin D test within the last 12 months as well as a SARS-CoV-2 test that was run through Quest.
The results showed that low vitamin D was linked to higher rates of SARS-CoV-2 positive test results. As vitamin D levels increase, the rate of positive test results decreases, up to a point.
Things to keep in mind:
- This study also shows that people with vitamin D level in the deficiency range (<20 ng/mL) were at a higher risk of SARS-CoV-2.
- Older people are more likely to have vitamin D deficiency, but in this study, more younger people were SARS-CoV-2 positive (thus not skewing the results towards deficiency due to age)
- The data showed a decrease in SARS-CoV-2 positivity rate up until vitamin D levels hit 55 ng/mL.
This recently published study was conducted by researchers at the University of Chicago using data on vitamin D status of patients from the previous year. There were 489 patients included in the study, and of those, 71 tested positive for the SARS-CoV-2 virus.
The results of the study showed that patients who had been deficient in vitamin D over the previous year were at an almost double risk of getting COVID-19.
A couple of things to keep in mind:
- Vitamin D levels may change in people who already have severe COVID and are in the hospital. This study gets around that problem of causality by using the vitamin D status from a previous visit to their doctor.
- This study was conducted during the first weeks of the COVID-19 pandemic in Chicago in March. Participants were excluded if they were taking supplemental vitamin D.
- The study group consisted of people who were admitted to the hospital with COVID symptoms (thus more severe than the majority of people) and also health care workers.
- Deficiency here was defined as below 20 ng/mL for 25(OH) D