The Importance of Vitamin D for Immune Health

Vitamin D is a very important vitamin that many people do not get enough of. It is a fat soluble vitamin known to play an important role in bone health. It helps the body absorb and retain calcium and phosphorus which are both critical for building bones. But vitamin D does so much more for the body and studies are showing the tremendous role it plays in the immune system. Vitamin D is nicknamed “the sunshine vitamin” because vitamin D2 and D3 are naturally occurring in the presence of the sun’s ultraviolet-B (UVB) rays. Many people do not get enough vitamin D due to lack of sunlight in the winter. Interestingly enough people tend to get sick more in the winter when they are getting less vitamin D through the sun. So why is vitamin D so important to immune health you ask? Well let’s find out. 

Vitamin D and the Immune System:

  • The active form of vitamin D modulates the damaging inflammatory response of some of some white blood cells, while it also boosts immune cells’ production of microbe-fighting proteins.
  • People who have low levels of Vitamin D are more likely to have had a recent cold, cough or upper respiratory infection.
  • Deficiency in Vitamin D is associated with increased autoimmunity and an increased susceptibility to infection. 
  • Newly recognized benefits of vitamin D include effects upon cell proliferation and differentiation as well immunologic effects resulting in an ability to maintain tolerance and to promote protective immunity.
  • Multiple cross sectional studies have shown that lower levels of vitamin D has been associated with increased infection. 
  • Vitamin D was used to treat infection like tuberculosis before the advent of effective antibiotics. Patients were sent to sanitariums where they were exposed to direct sunlight which was believed to directly kill the tuberculosis. 
  • Vitamin D plays an important part in the innate antimicrobial response.
  • Vitamin D deficiency is prevalent in autoimmune disease.

Other Benefits of Vitamin D:

  • Increases Muscle and bone strength
  • Reduces Inflammation
  • Lowers risk of cancer
  • Helps to keep arteries flexed and relaxed which helps to control high blood pressure.
  • Can reduce the risk of Diabetes. 

Food Sources:

  • Salmon
  • Egg Yolks
  • Mushrooms
  • Red meat
  • Beef liver
  • Dairy and plant milks fortified with Vitamin D
  • Tuna Fish
  • Oily fish
  • Fortified Cereals


It is very important for your health to make sure you are getting enough vitamin D. Vitamin D plays such a huge role in many different functions of the body.  It is especially important in the Winter when people are not getting enough sunlight. You can eat foods rich in Vitamin D or take a supplement. I have tried many brands and I use this brand and it works great! Find it here. As always it is best to consult your doctor if you have any health concerns.


“Vitamin D.” The Nutrition Source, 3 Mar. 2021, 

Aranow, Cynthia. “Vitamin D and the Immune System.” Journal of Investigative Medicine : the Official Publication of the American Federation for Clinical Research, U.S. National Library of Medicine, Aug. 2011,

Image by Igor Link from Pixabay

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