COVID-19 and Vitamin D

If you want a controversial vitamin, vitamin D takes the cake.  It isn’t even a vitamin in the sense that most vitamins are co-factors where this special vitamin is a prohormone that the skin can make itself with exposure to sunlight. Very weird. Vitamins are molecules generally obtained from the diet that do not become part of your body or used as energy like carbohydrates, protein or fat (the macronutrients) that help with growth and metabolism but are not minerals. What do we know about COVID 19 and vitamin D?

Vitamin D is the odd nutrient out in that it can be produced by the body when exposed to sunlight.  It makes this vitamin very unique and complicated to study.  Vitamins are “vital” to live and without vitamin D, you would get rickets or osteomalacia.

Do you know anyone with rickets in Canada?  No, you don’t, because the food supply is fortified with vitamin D to prevent this debilitating disease. 

But now we have COVID 19 and some evidence that people who had taken vitamin D had better outcomes in several studies. So what’s up with COVID 19 and vitamin D?

Innate Immune Response

This is the first response to an invading pathogen [virus, bacteria or other microorganisms] or an injury. It involves the release of cells [phagocytes, neutrophils, dendritic cells, mast cells, and eosinophils, among others] that ideally work in harmony to kill the invading pathogen, start the repair, and signal the adaptive response. While the innate response occurs quickly, the adaptive immune response is more specialized and often more effective. An example of an innate immune response: You catch a cold virus or COVID 19 and your body’s innate immune response causes you to develop a runny nose, cough, itchy eyes, etc.

Adaptive Immune Response

Adaptive immunity, although a much slower process, helps to defend the body against specific invaders. The adaptive immune response receives signals from the innate cells and can take days or weeks to develop. It has the ability to specifically recognize a pathogen and ‘remember’ it if the exposure were to occur again. An example of adaptive immune response: If you are exposed to the chickenpox virus > innate response is followed by “remembered” immunity. Of course, we now have a vaccine for this.  Soon we will have a COVID vaccine as well. 

• • Wild-caught fish such as salmon
  • Fatty fish (look for BPA-free cans or pouches, if possible)
  • Beef liver
  • Cod liver oil
  • Mushrooms 

Beyond food sources (and depending on the season), sunlight offers a natural and easy way for the body to absorb this essential vitamin, although this time of year, in Canada, we do not get enough produced so all Canadians are recommended to take 400 International Units (IU) of vitamin D, and for some populations, more.

Teriyaki Salmon

Savory Mushroom Soup

If warranted, additional supplementation of 1,000-4,000 IUs of cholecalciferol (vitamin D3) per day (depending on current levels) should be considered and individualized. If possible, find a vitamin D supplement that contains both K1 and K2 as this offers no risk of calcification of soft tissues and ensures that the vitamin D is metabolized appropriately. It is recommended that you discuss appropriate dosing, long-term use, and general supplementation information with a qualified healthcare practitioner, like a registered dietitian.

• • Pronounced interleuken-6 elevation 
  • Tumour necrosis factor-alpha elevation
  • Exaggerated interferon-gamma response
  • A shift towards amplified Th1 adaptive immune responses
  • Angiotensin-converting enzyme 2 suppression
  • Increased blood clotting

All this is the exaggerated response in the immune system; in other words, your immune system is in overdrive whether you are vitamin D deficient or infected with a virus like COVID 19. We do not want an overactive immune system when recovering from COVID 19. We want an optimal immune system. 

When it comes to immunological outcomes, optimal nutrition supports the function of immune cells and their response to pathogens and inflammation. Single micronutrients can exert multiple diverse immunological effects on the body, but excessive intake of some nutrients can also be associated with the impaired immune response so check with a healthcare provider before supplementation.

NOTE: Antioxidants are necessary for the reduction of increased concentrations of free radicals to protect cells against damage and restore cell signalling

The laboratory test for vitamin D is serum 25 (OH)D but it is not free for residents of British Columbia.  The reason why you can not get a free test is that people who do not supplement with Vitamin D, especially older adults, are likely to be deficient.  Therefore, the general consensus is that all Canadians should supplement year long with Vitamin D due to limited sun exposure due to altitude, indoor lifestyle and use of sunscreen.  Health Canada continues to recommend that people over the age of 50 years take a daily vitamin D supplement of 400 International Units (IU) (equivalent to 10 micrograms). 

It would be reasonable to consider paying for the test if you have already been supplementing for a while to check your levels. 

1) Evidence that COVID 19 patients who supplemented do better than patients who do not in case-controlled studies, intervention studies, observational studies and population studies.

2) Evidence that there is an overlap in the inflammatory processes which characterize vitamin D deficiency and severe COVID disease.

3) Evidence that good vitamin D status has improved outcomes with similar respiratory infections

4) That populations with better vitamin D status have better COVID outcomes.  For example, dark-skinned people who tend to have low vitamin D status, do worse when they are infected with COVID. 

Despite all these studies, we can not yet infer a causal relationship between vitamin D and improved outcomes with COVID 19 however they support that a vitamin D deficiency increases the risk associated with the COVID infection. It is possible that optimizing your vitamin D status will protect you from the increased risks of the COVID infection if you get it.

Things get confusing because correlation isn’t causation. Often the same people who take vitamin D supplements or have a healthy diet with adequate vitamin D will also exercise more, have less stressful jobs, don’t smoke, less obese, less diabetes and have better relationships. These people naturally recover more quickly from illness because of overall good health.  People who have diabetes and obesity also have poor outcomes with COVID 19 (e.g. obese people have 50% increase in dying – so maybe not a bad idea to talk a registered dietitian during these times about your weight.)  Or that people with darker skin are disproportionately poor, have less access to healthcare and good nutrition, have greater rates of obesity as well as making less vitamin D from sun exposure.

Everything gets murky here. Even with good study protocols, researchers control for these other factors, however, it is still very difficult to create studies without error. That makes studying these outcomes very difficult; was it the Vitamin D or was it the other factors?

There is no one magic nutrient that will protect you from the risks of a disease like COVID 19 and Vitamin D; however, making the lifestyle changes required to be a healthy weight for you, obtaining enough of all the nutrients that work together to provide anti-inflammatory benefits.  Good nutrition along with adequate healthy movement, good social connections and relationships all play a part in your healthy lifestyle.  

If taking 1000 – 4000 IU of Vitamin D daily is your next good habit you start, then you are on the right path to living the life you want to live. Download a free food tracker and learn more about having your diet assessed for the correct amount of vitamin D and any other nutrition questions you have, book a free call with a registered dietitian today!