Zip. Zero. Nada. As many expected, prior studies only were showing correlation and did not show causation. This is a high quality sufficiently large RCT that pretty much shuts down Vitamin D supplement claims.
Pretty huge news. Big (6,200) new RCT looking at vitamin D for the prevention of COVID-19 and respiratory illnesses found no benefit whatsoever from supplementation https://t.co/u1VsN4U2wJ
BACKGROUND Vitamin D metabolites support innate immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory pathogens. Randomized controlled trials of vitamin D to prevent coronaviru...
I thought vitamin D was being hyped as a treatment not for prevention?
Exactly.
Study looked at both prevention and outcomes. Hospitalizations and ventilation was actually slightly higher in the group that had Vit D supplements than the placebo group. Study is comprehensive and showed no benefit against COVID either in protection from infection or outcomes once infected. Vitamin D is a dud for COVID.
As a strong advocate of vitamin D, I'm disappointed in the outcome. I don't think it's definitive, though, for the following reasons that I can see on first reading.
1. It was not blinded; participants knew they were in the control group.
2. 49% of the control group admitted to taking supplemental vitamin D one or more times during the 6 months observation period.
3. And this is most interesting... the D levels of the control group rose from a mean of 39 to 66 at the end of the 6 month observation period. That's a 69% increase! My guess is that more people in the control group were sneaking some vitamin D on the side than was self-reported.
4. It takes a while for vitamin D to accumulate in the body, plateauing about 6-8 months after supplementation starts. It's possible that some of these infections might have come early in that build up stage before vitamin D reached protective levels.
5. The "high" dosage wasn't high at all... 3,200IU/day. Most advocates recommend supplementation of at least 5,000IU/day or more. I took 7,000IU +K2 during this same period.
6. The mean vitamin D level of the D group was 100nmol/L at the end... 40ng/ml as we measure in the US. I don't know if that is high enough to be protective. Over the past two years, my D level has been 59, 95, and 82 ng/ml... 50% to 137% greater than the mean of their vitamin D group.
7. Another variable is that vaccination rate varied from less than 5% to 90% of participants by the end of the study. Did the vaccine weaken the immune system as some claim? Did people get Covid or ARIs at a higher rate in the four weeks after vaccination? The vaccine is a bit of a wild card. It shouldn't have any effect on the efficacy of vitamin D... but does it?
Even with these shortcomings, I would have expected some statistical benefit from vitamin D so, again, I'm disappointed.
I'm curious to see what the experts who have been advocating vitamin D will have to say about this study.
