Vitamin D and Immunity



The second article in our immunity series will cover a study pertaining to Vitamin D and immunity. It is important to remember that while this article does talk specifically about Vitamin D and immunity, it does NOT relate specifically to covid. We have gotten quite a few questions related to certain supplements and their effects on Covid, and the reality is that not many reliable studies have been conducted examining supplementation and covid.


The reasons I chose this study in particular to write about were two-fold. First, it is one of the earliest studies to actually investigate Vitamin D and immunity in a randomized placebo control trial. Most studies up to this point were animal studies, population studies, or in vitro. The second reason I chose this study is the sample size. The study began with over 5000 participants, and completed with 3444 at the end. (As always happens in studies, people dropped out, didn't complete the survey at the end, or fell to the wayside for any number of reasons).


The study, published in 2007, started with a population of 5292 people with an average age of 77. Participants were split into 4 groups, one of which received vitamin D, one received calcium, one group received both, and the last group received a placebo. At the end of the study, only 3444 responded to the completion survey.


The study looked at numerous outcome factors among all the groups but we will focus on the immunity aspect. The groups that received Vitamin D reported having fewer infections and used antibiotics less than the groups which received no vitamin D supplementation. Participants who received vitamin D but still reported infections reported shorter time spent ill than non-vitamin D subjects.


What does this all mean?


While the results were interesting, they did not meet the criteria for statistical significance. However, the authors of the study noted that subjects who supplemented Vitamin D reported improved immunity related outcomes. Once again, this study is not related specifically to Covid, but we still maintain the importance of improving lifestyle factors that improve immunity as well as decrease co-morbidities. Vitamin D is an important supplement to take in the winter months. It is one of the more well researched supplements on the market, and is an essential vitamins (essential meaning that we require it but don't make it). Foods fortified with Vitamin D are not enough to significantly raise vitamin D levels, and where we live in Illinois, we don't get adequate sun exposure between November and March to raise vitamin D levels.

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