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FOR IMMEDIATE RELEASE
Estimating or Measuring? What is the true effect of vitamin D on COVID-19?
by Robert G. Smith, PhD
(OMNS June 12, 2021) A recent study used genetic methods to estimate the levels of vitamin D (blood levels of 25OHD) in individuals. The method is called "Mendelian Randomization" that estimates the metabolic activity in individuals using certain genetic mutations (SNPs) relevant to genes that are associated with 25OHD metabolism. By analyzing the genetic makeup of those who had COVID-19, the study concluded that vitamin D is not effective at reducing risk of COVID-19 infection. 
However, the study had several limitations. It did not actually test blood levels of 25OHD -- it only studied the genes involved in vitamin D metabolism. Although it was based on more than 14,000 individuals with COVID-19, and more than 1,200,000 individuals without COVID-19 from European ancestry, it excluded individuals of African and Asian ancestry. Moreover, the Mendelian Randomization method utilized in the study has not been shown to be effective for determining whether the estimated vitamin D status is associated with risk or severity of disease. 
The overriding problem with the study was that the vitamin D level of an individual (as opposed to a group) cannot be determined, even approximately, by their genetics. Someone who may be at risk of a low vitamin D level based on their genetic makeup may have sufficient sun exposure or adequate supplement doses to prevent a deficiency. Someone who is not at risk based on their genetic makeup may be deficient because of a lack of sun exposure or supplement doses. Further, by its exclusion of people with African or Asian ancestry, the study biased the accuracy of the analysis. Those individuals with dark skin living in at high latitudes such as Europe are well known by environmental studies to be at risk for a deficiency of vitamin D. [3-6] They can also prevent a vitamin D deficiency with sun exposure or supplements.
If the study had included people of African and/or Asian descent living in northern Europe, very likely it would have found a different conclusion -- that a deficiency of vitamin D contributes to risk of COVID-19. Certainly a study that would analyze the blood levels of 25OHD for risk of COVID-19 is likely to be more reliable.
Further, the study ignored other vitamins and minerals that are helpful for lowering risk of serious infection (levels of vitamin C, magnesium, zinc, selenium, etc) which are all synergistic. For example, the body's utilization of vitamin D is dependent on the level of magnesium, which is deficient in many individuals. 
In the last 6 months (Dec 2020 - May 2021), dozens of studies have been published showing a clear association between vitamin D deficiency and risk for COVID-19. [8-44] It seems unlikely that they are all wrong in the implication that there is a causal connection.
Vitamin D is not a drug, and its use should not be held up because of lack of causal proof of its efficacy in interventional trials. It is an essential nutrient, and its use as a supplement can safely and responsibly be recommended by doctors worldwide to assist in eliminating deficiency, improving health, and terminating the COVID-19 pandemic.
For the immune system to function well, the body requires adequate levels of many essential nutrients, not only vitamin D, but also magnesium, vitamin C, zinc, selenium, and other vitamins and minerals. Vitamin D supplements in safe, adequate doses along with other essential nutrients can aid and empower the immune system and prevent the cytokine storm that has caused so much mortality in severe pneumonia caused by COVID-19. [45-50]
For vitamin D, dose and blood level are important. The recommended adult dose is 5000 IU/day, but this should be adjusted for body weight. Since vitamin D is fat-soluble, heavier individuals may need a larger dose such as 10,000 IU/day. After taking a dose for several months, a blood test is advised; the ideal blood level of 25OHD is 50 - 60 ng/ml (125-150 nmol/L). A recommended adult dose of magnesium is 400-600 mg/day, including diet and supplements, but this also may need to be adjusted for weight. Recommended doses of vitamin C are 1500-3000 mg/day or more, taken in divided doses. You should discuss doses of essential nutrients with your doctor.
(Robert G. Smith is Research Associate Professor at the University of Pennsylvania, Perelman School of Medicine. He is the author of The Vitamin Cure for Eye Disease and coauthor of The Vitamin Cure for Arthritis. Dr. Smith is Associate Editor of the Orthomolecular Medicine News Service.)
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