Vitamin D for immunity

We are entering the time of year when colds and flus circulate. Oh joy! Today we are going to look at the role of Vitamin D on our immune system.

Did you know that on average children get about 12 colds/ year and adults tend to get about 2-4 colds/ year? YIKES that’s a lot of illness. As you can imagine this results in tons of lost productivity and of course miserable days had by all. There are a host of things you can do to improve your immunity this season, but I’m going to cover the evidence-based basics on why you should make sure you are taking Vitamin D.

Vitamin D. Indisputably one of the most important nutrients for the proper function of your immune system. We make vitamin D in our skin from exposure to UV rays from the sun. In Canada, being so far North of the equator, we don’t get enough of this essential nutrient making supplementation necessary. If you are in Alberta, you may know that Alberta Health Services is no longer funding vitamin D testing for everyone because most Canadians are deficient and they deem testing an unnecessary healthcare expense. Fair enough. Instead it is just recommended that we all take vitamin D.

What does vitamin D do for your immune system?

This is pretty cool actually. Vitamin D prevents the excessive release of cytokines.

What are cytokines you ask? They are immune chemicals we produce in response to an infection or injury. These immune chemicals are part of the fight to kill off an infection when present in the body. BUT they are the reason we feel so crummy when you get a cold or a flu. They cause aches, fever, pains, runny nose etc. We need the action of cytokines to fight infection, however sometimes they get released in excess. For example when people die or become severely ill from contracting the flu, it’s not the virus itself causing the death but your own immune reaction to the virus. Vitamin D helps to modulate this reaction. Still allowing for a normal immune response to the presence of the infection, but helping to prevent an over reaction to the virus. As you can imagine, this would result in a less debilitating cold or flu.

Vitamin D supplementation has been shown to reduce the occurrence of the flu in children. And we know that Vitamin D levels are inversely associated with the occurrence of Upper respiratory tract infections (a cold). Meaning that the lower your vitamin D status the more likely you are to contract a cold.

Who needs it the most?Young girl with white and pink robe holds a pillow to face

Those as highest risk for vitamin D deficiency are Canadians, kids with respiratory illness, older adults, women, obese individuals and those with darker skin.

I was inspired to write about vitamin D, since there are enough people I speak with here in Alberta who don’t feel the need to supplement with it. Everyone in this part of the world needs it. There are very few medical conditions that are the exception to that and if you have one of those your healthcare provider would have informed you.


How much do I take?img_1206

A good question. The level of vitamin D required for optimal health is hotly debated by experts. Health Canada currently doesn’t recommend over 1000 IU/ day, which many believe to be too low a recommendation. There have been many studies to support daily doses of up to 6,000 – 10,000 IU being safe for most adults. Some organizations and physicians think that doses above 2000 IU/ day require medical supervision. Recommendations should be based on deficiency risk factors (see above) and those on higher doses should be monitored. Ask your healthcare provider if you are confused about how much you should take.


Meaghan McCollum

Meaghan-130x150After graduating with a degree in nutritional sciences from the University of British Columbia, I went on to complete my naturopathic medical training at the Boucher Institute of Naturopathic Medicine.





Neve A, Corrado A, Cantatore F. Immunomodulatory effects of vitamin D in peripheral blood monocyte derived macrophages from patients with rheumatoid arthritis. Clin Exp Med. 2013:1–9

Sandarac M & Coleman L. Vitamin D and influenza. Adv Nutr Journ (2012) 3: 517-525

Urashima M et al. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr 2010;91:1255-60.

2 Responses to “Vitamin D for immunity”

  1. Sylvia Funk

    What do you look for in a brand of vitamin D? I have heard that vitamin D is difficult to absorb so you need to be particular about which brand. What are your thoughts on this.

    • Madison Isenor

      Hi Sylvia! We have some great Vitamin D options at Naturmend. You want to look for a Vitamin D without any fillers, all the brands we carry (bioclinic, AOR, Natural Factors etc) don’t have any included. We have liquid and capsules-liquid would absorbed quicker into the system as it would bypass digestive system. Hopefully this helps to clarify!

Leave a Reply