Demystifying Vitamin D

Vitamin D.  We keep hearing about this vitamin on the news.  The news is often conflicting and confusing:  We hear something about sunshine and not getting enough sun rays (but wear sunscreen so you don’t get skin cancer!), as well as hearing we need some but not “too much.”  I hope to take you on an adventure into the demystification of vitamin D,  teach you why it is important, how to get it in your body, and what actually happens when there is too little, too much, as well as how to find the perfect balance to support your body in resilience and good living.  


Why is vitamin D important for our body to be in a state of resilience?  Vitamin D plays many roles in our body.  The most familiar role is its part in how our body absorbs and uses calcium.  But a lesser known activity of vitamin D is that it plays an essential role in the regulation of our body’s immune system, specifically in our body’s defense against viral invasions. In May of 2020, researchers found that individuals who had low levels of vitamin D had more serious disease when their bodies became hosts to the virus known as Sars-CoV-2, the coronavirus that causes the illness known as COVID-19.


The Immune System and Vitamin D

To understand vitamin D and its role in protection against severe viral diseases, such as COVID-19, we must first understand a bit more about the immune system.  The immune system has many divisions that are each responsible for different activities.  One division is responsible for detecting the invasion, while another part is responsible for signaling the need for a specific kind of response to that particular type of infection.  Other divisions are responsible for the actual killing or neutralization of the invader, and other parts are responsible for “cleaning up” after the war.  Yet another division of the immune system is responsible for remembering the previous attack and helping the body respond more quickly and efficiently to future invasions (this is the division boosted by vaccinations).  Lastly, there is a division that helps identify when one of our own cells has become a problem, either by becoming cancerous or by being overtaken by a virus.  It is this last category where vitamin D may play an essential role.  


When a virus attacks our body, the virus actually inserts its genetic material into a particular kind of cell of the body (note: different viruses chose different host cells), then uses the host cell’s machinery to manufacture copies of itself.  Once a cell becomes infected and is now making hundreds of virus copies, the cell is no longer able to perform its usual functions, and, once it is filled up with the copies of the virus, the host cell explodes and dies, releasing brand new virus particles that then go and infect more cells. 


When fighting against a viral invasion, such as Sars-CoV-2, our body must quickly identify the infected cells, and then launch an initial generalized attack to destroy the infected cells.  The initial response is very generalized, meaning both infected cells and noninfected cells are destroyed.  This initial response must then be calmed down, or “de-escalated” in order for a more precision response to take its place.  Vitamin D appears to play a role in regulating, or “de-escalating” the response of the immune system once the immune system has started its initial attack against the virus-infected cells.   


To make this simpler, let’s imagine a typical day in a neighborhood in your body where yellow cars (lungs cells) are busy doing their job delivering groceries (oxygen).  The call comes in from “Immune Center Headquarters” that several of the yellow cars have been taken over by drivers (viruses) that no longer have the goal of grocery delivery, but instead intend to deliver less-than-nourishing items to the intended recipients. [-insert dramatic music here-].  To quickly prevent spread, “Immune Center Headquarters” initiates “flame thrower attacks” on all the yellow cars in the reported area of infection.  This generalized flame-thrower attack does indeed effectively destroy the cars that are infected, but also ends up annihilating healthy yellow cars that are not yet infected.  After a bit of initial chaos, “Team Vitamin D” is called in to put out the fires and turn off the flame-throwers, which then safely allows new specialized teams, equipped to identify and destroy only the infected yellow cars, to take charge of the situation [-insert hero music here-].


So vitamin D plays a key role in calming down the initial generalized immune response so that normal cells do not continue to be involved in “friendly fire.”  Imagine not having “team vitamin D” due to a low level of vitamin D in the body. The initial immune response is very necessary to quickly stop the early infectious stage, but if left unregulated, this generalized response can actually cause more harm than good.  Making sure very few “innocent cells” are impacted by the initial response requires vitamin D.


How Do We Get Vitamin D into Our Body?

So how do we get vitamin D into our body?  Most vitamins are in a class called water soluble.  This means that they can be dissolved in water, and, as a result, our body can get rid of any excess easily through our urine.  Vitamin D, however, is in a class of vitamins called “fat soluble.”   Fat soluble vitamins (Vitamins A, D, E and K) require several extra steps to get them out of the foods we eat as well as additional steps to distribute the vitamin and then store extra for future use when needed.  When we eat foods containing vitamin D, our liver produces a substance called bile that helps “collect” the vitamin from the food source, allowing the small intestine to absorb it into the lymphatics system.  Once in the lymphatic system, another “escort” protein is attached so that the vitamin can now be moved via the bloodstream.  When vitamin D is needed, it must then be converted to its active form in order to fulfill its duties throughout the body.  


As you now can see, there are many steps to successfully getting vitamin D into our body and then using it for its various roles.  At any one of these steps, things can interfere, making the process inefficient or not possible.    



Sunlight  plays two roles in the life of vitamin D. Cholesterol, when acted on in the skin by UVB sunlight, can be converted into vitamin D in the skin, producing small amounts of this important molecule.  Sunlight also assists the body in turning absorbed vitamin D into its active version.  Cellular systems can also activate vitamin D, but not as efficiently, so this is why some exposure to sunlight is needed for proper functioning of the systems that depend on vitamin D.  


Extra vitamin D is stored in our body fat and in the liver, and then mobilized when needed.  If a large amount of vitamin D is absorbed in a short amount of time, and all the storage capacity is full, the excessive vitamin D remains in circulation, as it can not be easily removed in our urine.  The excessive vitamin D in circulation then causes excessive amounts of calcium to be removed from bones and put into the bloodstream, resulting in weakness, abnormal heart rhythms, and occasionally death.  Having side effects from too much vitamin D takes an enormous amount of vitamin D, but excess vitamin D does not make us more resilient, so moderate amounts easily support our body’s needs. Just because some is good, does not make “more” better!  


Vitamin D in Our Diets

So where can we get vitamin D in our diet. Foods that contain vitamin D include fatty fish, such as salmon, tuna, herring and sardines.  Other sources of vitamin D, such as egg yolks and mushrooms, can vary widely in their content of this nutrient based on where/how they are raised.  Remember the role of sunlight?  It turns out, chicken egg yolks contain significant amounts of vitamin D, but only in chickens that eat foods that have been exposed to sunlight.  In other words, free range chickens allowed to forage in the sun make egg yolks that have high amounts of vitamin D, whereas chickens eating grain in commercial settings will not get the vitamin D unless their grain is enhanced with vitamin D.  


A non-animal source of vitamin D is wild mushrooms raised in the light (Note: most commercial mushrooms are grown in the dark, therefore are of little value as a source of vitamin D).  Plant sources contain a version of vitamin D called D2.  D2 appears to be a bit more difficult for humans to absorb than the vitamin D3 version, found in the egg yolks and fish.  Vitamin D2 must be consumed in significantly higher concentrations to achieve the same active vitamin D levels as lower doses of vitamin D3.  

Vitamin D Supplements

As those of you who are familiar with my approach to health know, I rarely encourage any form of supplementation, as the body is much better at removing important nutrients from the original source than removing from a man-made version.  However, as you may have noticed, good sources of vitamin D can be hard to find in our new food jungle and vitamin D deficiency appears to be fairly common throughout the United States.  While our TLC participants are actively working on replacing processed foods with natural options, 400-800 IU once daily supplementation of D3 softgel caps is something I recommend taking daily for 3 months. In the United States, Vitamin D3 supplements are available over the counter in both tablet and softgel formulations, with vitamin D2 available only by prescription.  In my experience, the over-the-counter D3 gel caps are much more effective at raising blood levels of active vitamin D over a three-month period than either the D3 tablets or the D2 tablets.  Ideally, the supplement should be taken once daily with a meal, and even better if that meal contains dietary fat, as this enhances secretion of the bile that aids in its absorption.  Unless you have had a blood test and are being guided by a physician, it is unwise to take higher doses than 800 IU due to the side effects of overdosing mentioned earlier.


So, the bottom line is vitamin D is needed in sufficient amounts for multiple roles, including bone strength as well as immune system regulation.   Our immune system fights viral infections by first initiating a generalized blanket attack, which kills cells infected by the virus, but also normal cells.  When low in vitamin D, our immune system lacks an essential tool responsible for turning down the activity of the immune system when the initial attack is completed.  If the first wave of controlling an invasion of our own cells is not gently turned into a more precision battle, with specialized teams taking over the battlefield, normal uninfected cells continue to die, and the damage done by the immune system becomes a bigger problem than the damage caused by the actual virus.  Thus, low vitamin D can cause unregulated attack of normal cells in our body by our own immune system.  



If you are in the process of rehabilitating your gut and/or do not like the dietary sources of D vitamin, this is a time when properly selected supplements can play a temporary role in achieving resilience.  I recommend over-the-counter D3 gelcaps.  A dose of 800-1,000 IU taken once daily with a fatty meal will get your vitamin D levels up over a 3 months period.  After the initial 3 months and after establishing good gut health habits, you can effectively maintain your vitamin D needs from foods. 


Getting vitamin D from diet sources can be challenging, but is not impossible.  Once your gut is healthy, include some salmon, herring, or sardines to a meal or two each week, combined with an additional couple of meals that include 1-2 beautiful orange-yolked pasture-raised chicken eggs, and then throw in those occasional wild mushroom dishes and you will likely get enough vitamin D to maintain proper levels in circulation as well as in storage.  Canned tuna is also a good source to add to the mix of vitamin d rich meals.


Sunlight does play an important role in the vitamin D activity of our body, but you should wear sunscreen to protect against the known negative impacts of the sun.  Unless you literally bathe in sunscreen, you will have enough of your skin surface interacting with vitamin D to maintain appropriate vitamin D function. 


Being healthy can be easy, but it does take consistency.  Learn how to add vitamin D foods to your menu on a regular basis and you will have taken an important step in your body’s vitality and ability to take on unexpected challenges!