Several studies have suggested that this may not be a bad idea, but there are many variables to consider. Here's the evidence so far. One study in Spain reported that 80 percent of the COVID-19 patients in the hospital conducting the study had deficient vitamin D levels. The Mayo Clinic did a study of 489 individuals being tested for COVID-19. They reported that patients who had a vitamin D deficiency were more likely to test positive.
One small study looked at high dose vitamin D supplementation in patients who were hospitalized with COVID-19 and found supplemental vitamin D was associated with dramatically improved outcomes. Just one out of about 25 patients who received vitamin D required treatment in the ICU, while 13 out of 26 who did not receive vitamin D had to be admitted to the ICU.
Another very recent study reported that vitamin D or Omega-3 supplements were associated with a reduction in rates of infection (including COVID-19) in a group of over 2,000 people age 70 years or older.
The possibility is intriguing enough that multiple clinical trials (currently 60 are listed in clinicaltrials.gov) are underway evaluating the impact of vitamin D on COVID-19.
Vitamin D deficiency is common in the Northwest; it's probably due to the sometimes intense cloud cover and resulting lack of solar exposure we experience particularly in the winter. Given the important role we know vitamin D plays in immune function and hundreds of important biochemical reactions in our bodies, the lack of vitamin D toxicity if taken in reasonable doses, and the low cost, it makes sense to consider supplementation. It's interesting to note that Dr. Anthony Fauci has indicated that he takes supplemental vitamin D (as well as C). If you want to consider taking supplemental vitamin D, please talk to your prescriber or your pharmacist first about an appropriate dose. Vitamin D can be toxic if taken in large doses.
John R. White is the chair of the Department of Pharmacology at WSU College of Pharmacy and Pharmaceutical Sciences based in Spokane.