A pilot study was conducted in Spain including 76 patients with COVID-19 pneumonia who were randomized into two groups - 50 patients received vitamin D supplements (approx. 30,000 IU daily for the first week, followed by 7,600 IU daily) whereas 26 patients did not (control group).
It was found that 50% of patients in the control group required ICU admission whereas only 2% of those who took vitamin D supplement were admitted to the ICU. The difference was statistically significant meaning vitamin D can significantly reduce the risk of ICU admission in patients with COVID-19 pneumonia. Moreover, in the control group, there were two deaths whereas in the vitamin D group, there were no deaths. Though the difference was not statistically significant.
Although the sample size was relatively small, the findings strongly suggest that maintaining adequate vitamin D levels should be a strong part of the public health messaging around protecting against COVID-19.
In my opinion, everyone should get their vitamin D levels tested at least once a year (ideally during autumn/ prior to winter) and take vitamin D supplement accordingly to achieve the optimal level. This is because there is no ‘one size fits all’ dosage recommendation for vitamin D supplement. Vitamin D requirement for each individual depends on several factors such as ethnicity, genetic variants (e.g. changes in vitamin D receptor gene activity), diet, lifestyle and health status. People with chronic conditions like diabetes, autoimmune disease, or cancer, may need to target a vitamin D level higher than the standard range, which are between 75 and 150 nmol/L (or 30-60 ng/ml) for a healthy population. It makes sense to aim for the upper end level if you are overweight or have a health condition. Also, it is important to ensure adequate levels of cofactors, e.g. magnesium and vitamin K2, especially if you are taking a calcium supplement as these nutrients are essential for calcium absorption and for bone and heart health.
Castillo, M E. et al. (2020) Effect of Calcifediol Treatment and best Available Therapy versus best Available Therapy on Intensive Care Unit Admission and Mortality Among Patients Hospitalized for COVID-19: A Pilot Randomized Clinical study. J Steroid Biochem Molecular Biol. In press.