Vitamin D and the Immune System

Vitamin D is required for a properly-functioning immune system.

Individuals with deficient levels of Vitamin D have a higher probability of developing diseases related to a poorly-functioning immune system.

The level of Vitamin D, specifically 25-(OH)D3, needed is much higher than was realized 20 years ago when Michael Casparian, MD, and I wrote an article on Vitamin D. At that time, the optimal level of 25-(OH)D3 in a person’s blood was considered to be 30 – 40 ng/mL. However, new research has now shown that to achieve an optimal level that enables the immune system to fight off pathogens such as Covid-19, the level of 25-(OH)D3 must be at least 50 ng/mL.

The winter months in the Northern Hemisphere are when flu and Covid cases spike. January and February could be really bad months for Covid.

This is because it is impossible to achieve and maintain optimal levels of 25-(OH) D3 during the winter months in the Northern Hemisphere as the angle of the sun prevents UVB radiation from penetrating the ozone layer to activate pro-hormone D in bare, exposed skin. Sun-bathing in the winter in Chicago would be uncomfortable and useless for increasing your Vitamin D levels.

Eating several servings per day of oily fish like sardines will help raise your Vitamin D levels somewhat, but that is really the only food you could eat that would raise Vitamin D levels. The amount of Vitamin D3 you can get from other food sources is too tiny to help.

The best course of action during the winter months is to take a Vitamin D supplement that does NOT include calcium. Optimized Vitamin D levels maintain appropriate calcium regulation without taking supplemental calcium. Milk actually doesn’t do most bodies good. Excess calcium can create its own health problems such as weaker bones or kidney stones.

If you live in the Northern Hemisphere, it is highly probable that your levels of 25-(OH)D3 are far below the optimal level of 50 ng/mL. During the Pandemic, I have been taking 4000 IU/day of Vitamin D3. I will increase this to 6000 IU/day during January and February. I am also fully vaccinated with Pfizer, including a booster shot. And I wear a mask indoors or in crowds outdoors.

The Omicron variant is much more infectious than the Delta variant. As of this writing, we do not know how it compares in terms of disease and death, but it is best practice to do all we can to avoid any illness, however ‘mild’ it may be. A ‘mild’ case can still be debilitating.

Actions to take to minimize the possibility becoming ill with Covid or the Flu:

1. Get vaccinated (and boosted).
2. Wear a mask indoors and in crowds outdoors.
3. Take a daily supplement of Vitamin D3.