Mercola by Dr. Joseph Mercola 7/7/2022
Story at-a-glance • Recent research assessing the effectiveness of vitamin D supplementation for the prevention of COVID-19 in frontline health care workers found only 6.4% of those taking vitamin D tested positive for COVID, compared to 24.5% of controls
• The treatment group received 4,000 international units (IUs) of vitamin D per day for 30 days. The use of fixed dosing is a shortcoming of this study, as the most accurate way to assess vitamin D’s benefits is by comparing the effects of different serum vitamin D levels
• Data from GrassrootsHealth’s D*Action studies suggest the optimal level for disease prevention and good health is a vitamin D level between 60 ng/mL and 80 ng/mL. The cutoff for sufficiency appears to be around 40 ng/mL
• Sun exposure is exponentially superior to oral supplementation, as it not only triggers vitamin D production but also melatonin production inside your mitochondria
• Melatonin has been shown to be an important part of COVID treatment, reducing incidence of thrombosis and sepsis and lowering mortality. Evidence suggests sun exposure may help combat any number of respiratory infections, including COVID, and the production of melatonin in your mitochondria — not merely vitamin D production — appears to be a key part of how and why that works
Early on in the COVID-19 pandemic, it became apparent that vitamin D played an important role and could help reduce incidence of positive tests, infection severity and the risk of hospitalization and death.
The evidence of benefit was so clear, I published a scientific review1 in the journal Nutrients at the end of October 2020, co-written with William Grant, Ph.D., and Dr. Carol Wagner, both of whom are part of the GrassrootsHealth expert vitamin D panel.
This paper, "Evidence Regarding Vitamin D and Risk of COVID-19 and Its Severity" — which you can download and read for free — ended up being the second-most downloaded Nutrients paper in the 12 months following its publication.
The study with the most downloads that year and the all-time highest number of views (178,562) for any Nutrients paper was another vitamin D study2 by Bhattoa et.al., which found vitamin D supplementation reduced the risk of both influenza and COVID-19 infections and deaths. One of the coauthors of my paper, Grant, was a coauthor on this paper as well.
Several other vitamin D papers topped the lists of views, downloads and citations as well, which was a testament to the fact that many were in fact paying attention to the data rather than blindly believing media claims that there was "no scientific basis" for the recommendation of vitamin D for COVID.
Why Sun Exposure Is the Best Way to Optimize Vitamin DWhy use sun exposure rather than oral vitamin D? The short answer is that sun exposure gives you far more bang for your buck. Not only is it free, but it also provides a plethora of biological health benefits over and beyond vitamin D production.
In summary, your mitochondria produce ATP, the energy currency of your cells. A byproduct of this ATP production is reactive oxidative species (ROS), which are responsible for oxidative stress. Excessive amounts of ROS will damage your mitochondria, contributing to suboptimal health, inflammation and chronic health conditions such as diabetes, obesity and thrombosis (blood clots).
The good news is your body has a built-in way to counteract these ROS. Inside your mitochondria, you also have an antioxidant system, and the main antioxidant is melatonin. Melatonin also upregulates your glutathione pathway, which is another potent antioxidant pathway. So, your body is literally designed to address the destructive impact of energy production, but you need sun exposure in order for that mechanism to work.
Sun Exposure and the Prevention of Viral InfectionsInterestingly enough, melatonin has also been shown to be an important part of COVID treatment, reducing incidence of thrombosis and sepsis11 and lowering mortality.12,13
Evidence suggests sun exposure may help combat any number of respiratory infections, including COVID, and the production of melatonin in your mitochondria appears to be a key part of how and why that works.
There are a number of observations showing COVID rates across the world correlate to the solar index or the amount of sun striking the area. Positive case rates also correlate with vitamin D levels in the blood. Higher blood levels correlate with lower incidence of COVID and higher rates of survival for inpatients.
The same correlation does not always appear when using oral supplementation, however. Here, studies have produced mixed results. Some studies looking at the effect of giving vitamin D to patients with severe COVID, for example, found no benefit, even at very high doses. So, what's going on?
In short, your vitamin D level may simply be a marker for sun exposure. Many of the benefits of sun exposure may actually be due to factors that are unrelated to vitamin D. For example, research14 looking at UVA levels and COVID mortality rates found areas of the U.S., the U.K. and Italy with higher UVA also had lower COVID mortality rates.
Vitamin D does not rise in response to UVA, only UVB, so, something in the sunlight other than vitamin D must be responsible for the beneficial impact. In that particular study, they speculated that nitric oxide, which is produced in response to UVA, could be the key, as nitric oxide has been shown to limit SARS-CoV-2 replication in vitro.
But while it's true that nitric oxide rises in response to sunlight (specifically UVA and near-infrared), the primary mechanism at work may in fact be melatonin, because it's produced in response to the infrared spectrum — which makes up a much greater portion of the solar spectrum than ultraviolet — and works regardless of the angle at which it hits the earth.
Melatonin and Sunlight Are Intimately ConnectedMelatonin and sunlight are intimately linked and their relationship is unique in the fact that there are two forms of melatonin, circulatory and subcellular, or that produced by your pineal gland and secreted into the blood, and that produced by your mitochondria and used there locally.
Vitamin D Level Is Directly Correlated to COVID-19 OutcomeOne of the reasons why vitamin D is so important against COVID-19 has to do with its influence on T cell responses. Animal research22 published in 2014 explained how vitamin D receptor signals regulate T cell responses and therefore play an important role in your body's defense against viral and bacterial infections.
As noted in that study, when vitamin D signaling is impaired, it significantly impacts the quantity, quality, breadth and location of CD8 T cell immunity, resulting in more severe viral and bacterial infections.
What's more, according to a December 11, 2020, paper23 in the journal Vaccine: X, high-quality T cell response actually appears to be far more important than antibodies when it comes to providing protective immunity against SARS-CoV-2 specifically.
More:
https://articles.mercola.com/sites/articles/archive/2022/07/07/vitamin-d-prevents-covid-19.aspxhttps://www.youtube.com/watch?v=aXw3XqwSZFo&t=7s
