Vitamin D deficiency is one of the most common and underdiagnosed nutrient deficiencies we see globally. It is estimated that approximately 41.6% people in the U.S. and 1 billion people worldwide are classified as vitamin D deficient when compared to conventional ranges (30-100 ng/mL).
Vitamin D deficiency is linked to many chronic conditions, including cancers, high blood pressure, diabetes, depression, osteoporosis, fibromyalgia and multiple sclerosis. Symptoms of low vitamin D include chronic low energy, brain fog, PMS, depression, frequently getting sick, and long recovery times from illness.
Vitamin D is crucial for the functioning of the immune system, which is our body’s first line of defense against infection and disease. It has both anti-inflammatory and immunoregulatory properties to stimulate the activation of our immune system defenses.
Despite how important vitamin D is for our overall health, we are still not getting enough! There are a few major reasons for this. For one, during the colder months, it is harder for individuals to receive appropriate sunlight exposure. When our skin is exposed to sunlight, it produces vitamin D. The sun’s ultraviolet B (UVB) rays interact with a protein known as 7-DHC in the skin, which then converts to the active form of vitamin D (D3) in our body. It can also be quite difficult to get adequate vitamin D from food sources, especially if you do not eat eggs and seafood frequently enough.
There is a substantial clinical difference between what is considered a “normal” serum vitamin D status by conventional terms and what is considered “optimal” for a unique individual. In traditional medicine, a “normal” vitamin D status is considered between 20-40 ng/mL. However, I am typically recommending that my clients strive for a more optimal level of at least 50 ng/mL (which, of course, is further dependent on the individual person and their specific nutrient needs.
There is a substantial clinical difference between what is considered a “normal” serum vitamin D status by conventional terms and what is considered “optimal” for a unique individual.
Vitamin D2 vs. D3 - What the Heck is the Difference?
The vitamin D that we receive from food sources, sun exposure, and supplementation comes packaged in two different forms: vitamin D2 and D3. Both forms of vitamin D are fat-soluble and effectively absorbed in the bloodstream, but the liver metabolizes them very differently. That said, Vitamin D2 and D3 are not equal when it comes to their contributions to your vitamin D status.
Let’s break down the difference a little further…
The liver metabolizes vitamin D2 to 25-hydroxyvitamin D2 and vitamin D3 into 25-hydroxyvitamin D3, both collectively known as calcifediol.
Many studies have shown that vitamin D2 produces less calcifediol than vitamin D3 and vitamin D3 is more effective at raising blood levels of calcifediol. In the case of vitamin D deficiency and suboptimal levels, this may be an important consideration when choosing supplements.
Vitamin D2 (ergocalciferol) → (Less Active form) is found in plant-based food sources such as mushrooms (exposed to sunlight or IV light), fortified foods - i.e. cereals, plant-based milks, and orange juice, and also through supplementation.
Vitamin D3 (cholecalciferol) → (More Active form) is found in animal-based food sources such as oily fish and fish oil, liver, egg yolks, and butter. It is also taken in through appropriate sun exposure and dietary supplementation.
The Synergistic Role of Vitamin D, Vitamin K and Calcium
Some studies have shown that better absorption of vitamin D is improved by consuming other fat-soluble vitamins such as vitamin A and vitamin K. That is why, when working with clients who have suboptimal vitamin D levels, I am typically recommending a vitamin D3 + K2 supplement in addition to optimizing food sources.
Vitamin D and vitamin K both play a large role in regulating calcium. Specifically, vitamin D aids in the absorption of calcium and helps to maintain the balance of calcium in the blood.
Vitamin K, on the other hand, initiates the activation of a protein called osteocalcin, and serves as a taxi cab to shuttle calcium to appropriate storage in places like our bones and teeth. Think of it this way - picture a busy New York City street - people swiftly moving through the city sidewalks and flagging down taxi cabs to travel to their next destinations. The same is true for calcium. As osteocalcin is activated, the taxi cabs come swooping in to redirect calcium to the appropriate storage units. Vitamin K also activates the matrix GLA protein to prevent calcium build up in soft tissues like your organs.
This is why it is incredibly important (when supplementing) to avoid taking vitamin D without the presence of vitamin K. Too much vitamin D without vitamin K can contribute to an overaccumulation of calcium in the blood vessels or kidneys (which we certainly do not want!).
However, just like vitamin D, vitamin K also comes in two forms: vitamin K1 and K2. Vitamin K2 (specifically in the form of MK-7) is considered the most effective for supplementation, but we can also find both vitamin K1 and vitamin K2 readily available in food sources:
Vitamin K1 can be found in dark leafy greens, cauliflower, Brussels sprouts, and cabbage; and
Vitamin K2 can be found in fermented foods like kimchi, sauerkraut, and animal sources such as liver, egg yolks, and chicken. Our gut bacteria (when healthy!) also does a great job of producing some vitamin K2!
Vitamin K can be found in dark, leafy greens like kale and spinach and assists in the mechanism of blood clotting. It also helps with calcium metabolism and bone health.
Vitamin K just like vitamin D comes in two forms - K1 and K2, but it is even more advanced and breaks into MK-4 and MK-7. Vitamin K2 is the most well-researched form of vitamin K and does the best job at transporting calcium to appropriate storage.
As an important side note, if you are on blood thinners, taking coumadin, or have blood clotting issues, then vitamin K can be contraindicated. Remember to always consult your healthcare practitioner before taking any new supplement.
A Note on Supplements and Vitamin D Optimization
Before jumping in to purchasing any new supplement, I highly recommend the following:
First and foremost, make sure you are getting your vitamin D labs checked regularly. If your values are within normal limits, I recommend a blood test at least once annually. However, if your vitamin D values are low, I recommend checking your labs every 3-6 months. Since vitamin D is a fat-soluble vitamin, there is a toxicity level that can be obtained by taking too much of the vitamin in supplementation form. An optimal range to shoot for, key word: optimal, is between 40-70 ng/ml. You want to make sure you are taking the right amount of vitamin D!
Work with a practitioner! Whether this is a physician, registered dietitian, or trained specialist, do not purchase any new supplements without the recommendation and approval from a practitioner. Every person has a unique medical history, genetic makeup, and vitamin D needs so it is crucial to seek guidance before investing in any new supplements.
Not all supplements are created equal! Work with your practitioner to find a high-quality, medical grade supplement in the form of vitamin D3. Even better, shoot for a vitamin D3/K2 combination for optimal vitamin D absorption and calcium storage.
Have patience. Remember, a deficiency status does not develop overnight. It can take months to years to progress to this. That said, keep in mind that correcting a vitamin D deficiency will not happen immediately. It can often take upwards of 6-10 months for your body to restore vitamin D status to optimal levels.
When supplementing, be sure to take your supplement with a fat source for optimal absorption. Both vitamin D and vitamin K are fat-soluble vitamins, and thus, when taken in the presence of a fat source (think nuts, seeds, olive oil, avocado, nut butters, etc.) it will increase the rate of absorption.
And finally, while always considering a “food first” approach, try to incorporate more dietary sources of vitamin D:
Fatty fish such as wild caught salmon, mackerel, and sardines
Fish liver oils, such as cod liver oil
Eggs, including the yolk
Vitamin D is crucial for so many aspects of our health. The end goal is to strive for health that reflects not just the “absence of disease” but the optimization of wellness. Establishing appropriate vitamin D levels is one of the most fundamental aspects of reaching this goal.
If you are considering how to enhance your vitamin D status or are curious about proper supplementation, schedule a consult with me through my website to learn more!
Interested in learning more about your vitamin D status? Book a 1-on-1 session with me!