Vitamin D, RDA, COVID-19 and You!

Dr. Garreth MacDonald


Vitamin D, RDA, COVID-19 and You!


Many of you may not be aware of the growing research on the relationship between low levels of vitamin D and COVID-19 severity.


The importance of vitamin D with respect to immunity, cancer, neurologic diseases, joint pain, autoimmune disorders, depression, just to name a few, is vast in the literature. Its impact on respiratory diseases has long been well-known. So much so, I was surprised how little publicity vitamin D received when this new respiratory disease showed up (however see my last blog post on Vitamin D and COVID, May 2020)


I consider myself an orthopedic chiropractor, not a nutritionist, but I was quick to recommend to my patients to get their vitamin D levels up when COVID hit the scene. I’ve heard nothing but reinforcement about this since.


The latest discovery was that the RDA for vitamin D was wrong, by more than a factor of 10. The recommended 600 IU/day cannot raise D levels into the normal range. The actual calculated RDA was supposed to have been 8895 IU/day. This was pointed out in 2014 in the journal Nutrients. In the article titled “A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D” the authors pointed out

One of these recommendations is the Recommended Dietary Allowance (RDA). The RDA is the nutrient intake considered to be sufficient to meet the requirements of 97.5% of healthy individuals. The RDA for vitamin D is 600 IU per day for individuals 1 to 70 years of age and is assumed to achieve serum 25-hydroxyvitamin D (25(OH)D) levels of 50 nmol/L or more in 97.5% of healthy individuals.”

The authors concluded that:

The public health and clinical implications of the miscalculated RDA for vitamin D are serious. With the current recommendation of 600 IU, bone health objectives and disease and injury prevention targets will not be met”.


This was not the only such publication, and despite this dire observation no correction was ever made. Furthermore, medical doctors were cautioning patients not to take too much, and people became afraid to take more. Now, by some estimates, 42% of Americans are deficient, vulnerable to infection as well as many chronic and debilitating health issues. As low vitamin levels are worst among the elderly, and in part it helps explain their vulnerability.


As it is so unusual for someone with normal vitamin D levels to die from COVID, I have to ask the question, without such a mistake, why isn’t testing D levels a priority recommendation, particularly in nursing homes and communities for the elderly?


Because raising vitamin D levels can take time, it is probably not a valid treatment option once someone is sick, but I would recommend all communities, including ours, get it tested and respond appropriately.


This is by no means medical advice to you, nor am I making a “miracle cure” recommendation. I am simply pointing out some connections to this article and my previous COVID-19 and Vitamin D Blog post. I would recommend, before downing large dose of Vitamin D, to get tested and know exactly where you are. Then take some Vitamin D and in 90 days retest to see if the dosage you took made a difference and achieved the levels you were looking for. GO GET TESTED.


Dr. Garreth MacDonald

Chiropractic Physician

Cascade Health Center



Veugelers PJ, Ekwaru JP. A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients. 2014;6(10):4472-4475. Published 2014 Oct 20. doi:10.3390/nu6104472.

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