The evidence is growing that those with low vitamin D levels are at a higher risk for respiratory infections, including COVID-19. However, purists argue that we need more evidence and better evidence from randomized trials. This is quite irresponsible considering that we have so much correlational data and that the risk of taking vitamin D is minuscule. You can read some of the debates on this question in the recent issue of the Irish Medical Journal.
As I mentioned in a recent post, it is important to keep your vitamin D level not only in the normal range, which in most laboratories is between 30 and 100, but at least in the middle of this range.
One piece of supporting evidence is the fact that patients with multiple sclerosis (MS) whose vitamin D level is in the bottom quartile of the normal range are four times more likely to have a flare-up of their MS than those in the top quartile. Another MS study showed “…profound association of 25(OH)D levels with MRI measures of disease activity and progression” Those with vitamin D deficiency were also found to have higher risk of developing Alzheimer’s disease.
The above-mentioned evidence is not necessarily transferable to respiratory infections, however, multiple sclerosis is an autoimmune inflammatory condition, while Alzheimer’s has an inflammatory component and it is possible that inflammation could be where vitamin D exerts its beneficial effect.
So the debates need to end and everyone should take at least 50 mcg (2,000 units) of vitamin D. An important fact to keep in mind is that some people do not absorb vitamin D well so if you were found to be deficient, it is a good idea to recheck your level since you may need to increase the dose.
