Vitamin D & K2 Research

When we think about supporting our health, we often focus on eating well, staying active, getting enough sleep and managing stress. But what about the nutrients our bodies need to carry out some of their most important functions?Vitamin D is one of those nutrients that deserves a little extra attention, particularly for those of us living here in Atlantic Canada.

We are going to explore why vitamin D is so important, why supplementation may be beneficial, and what makes the combination of vitamin D3 and K2 worth considering.

Why is vitamin D so important?

Often referred to as the sunshine vitamin, vitamin D is a fat-soluble nutrient that functions much like a hormone within the body. It plays an important role in several physiological processes, extending far beyond what we traditionally associate with bone health.

Some of its most important functions include:

1. Building and maintaining strong bones and teeth

One of vitamin D’s best-established roles is helping the body absorb calcium from the digestive tract. Without adequate vitamin D, our bodies cannot effectively absorb the calcium needed to maintain healthy bones.

2. Supporting immune system function

Vitamin D plays an important role in regulating both the innate and adaptive immune systems. Vitamin D receptors are found on many immune cells, and the nutrient helps support normal immune responses.

3. Supporting muscle function

Vitamin D contributes to normal muscle function and neuromuscular health. Inadequate levels can contribute to muscle weakness, which is particularly important as we age and work to maintain strength, balance and mobility.

4. Supporting overall health

Vitamin D receptors are found throughout the entire body, and researchers continue to investigate its involvement in inflammation, cellular growth and metabolic processes.

Why is vitamin D supplementation particularly important in Canada?

Living in Canada presents some unique challenges when it comes to maintaining adequate vitamin D levels.

Our bodies naturally produce vitamin D when our skin is exposed to ultraviolet B (UVB) rays from sunlight. However, several factors influence how much vitamin D we can produce.

Geography: At northern latitudes, including here in New Brunswick, the sun’s angle during the fall and winter months limits the amount of UVB radiation available for vitamin D production.

Season: Even when we spend time outdoors, our skin may produce very little vitamin D during the winter months because most of it is obviously covered.

Lifestyle: Many of us spend most of our days indoors, particularly during colder months.

Age: Our ability to produce vitamin D through the skin decreases as we get older.

Diet: Vitamin D occurs naturally in relatively few foods. Fatty fish, egg yolks and fortified foods provide some vitamin D, but obtaining enough through diet alone can be challenging.

For these reasons, supplementation can be a practical way to help maintain adequate vitamin D intake throughout the year, particularly during the fall and winter.

Why combine vitamin D3 with vitamin K2?

Although vitamin D3 and vitamin K2 have different functions, they work together in several important ways, particularly when it comes to bone health and calcium metabolism.

Think of it this way:

• Vitamin D3 helps your body absorb calcium.
• Vitamin K2 helps activate proteins involved in calcium utilization and regulation.

Let’s look at each nutrient a little closer.

Vitamin D3: Helping your body absorb calcium

Vitamin D3 (cholecalciferol) is the form of vitamin D naturally produced by our skin in response to sunlight.

One of its primary roles is increasing calcium absorption from the digestive tract, helping ensure calcium is available for important functions, including bone mineralization.

Vitamin K2: Helping activate calcium-regulating proteins

Vitamin K2 is a form of vitamin K that plays an important role in activating certain proteins through a process called carboxylation.

Two particularly important proteins are:

Osteocalcin

Osteocalcin is produced by bone-forming cells. Vitamin K is required to activate osteocalcin, allowing it to bind calcium and contribute to normal bone mineralization.

Matrix Gla Protein (MGP)

MGP is a vitamin K-dependent protein found in tissues including blood vessels. It helps regulate soft-tissue calcification (there is ongoing research into a connection with preventing cardiovascular disease).

The interesting part is that vitamin D helps regulate the production of some of these proteins, while vitamin K is required for their activation.

What does the research say about taking vitamin D3 and K2 together?

Research into combining vitamin D and vitamin K has been particularly interesting in the area of bone health.

A 2020 meta-analysis examining eight randomized controlled trials involving 971 participants found that combining vitamin D and vitamin K was associated with improvements in total bone mineral density and reductions in undercarboxylated osteocalcin.

A 2024 review also examined clinical studies involving combined vitamin D and K supplementation, identifying potential benefits for bone and cardiovascular health in postmenopausal women.

While these findings are encouraging, there are some important considerations:

• Studies have used different forms and doses of vitamin K.
• Results are not consistent across all populations.
• Larger, longer-term clinical trials are still needed to establish the impact on fractures and cardiovascular events.

How much vitamin D should you take?

There isn’t necessarily a one-size-fits-all answer when it comes to vitamin D supplementation.

Your individual needs can depend on your age, dietary intake, sun exposure, lifestyle, health history and existing vitamin D status (which you can obtain via bloodwork through your medical provider).

For adults, 1,000–2,000 IU of vitamin D3 daily is a commonly used supplemental range, although some individuals may require less or more depending on their circumstances.

A few important things to remember:

• Vitamin D is fat-soluble, so taking liquid drops that are emulsified in a fat is preferred over tablets which you must eat alongside an adequate amount of dietary fat
• Consistency matters more than taking large, occasional doses.If you have concerns about your vitamin D status, speak with your healthcare professional about whether testing or individualized supplementation is appropriate. A blood test measuring 25-hydroxyvitamin D can help assess vitamin D status when testing is clinically indicated.

An important note about vitamin K2: Individuals taking warfarin or other vitamin K-sensitive anticoagulants should consult their prescribing healthcare professional before starting or changing vitamin K supplementation. Consistency in vitamin K intake is particularly important with these medications.

Our takeaway at East Coast Chiropractic

At East Coast Chiropractic, we believe that supporting your health starts with understanding the foundational things your body needs to function well.

Vitamin D is an important nutrient for bone health, muscle function and normal immune system function. For those of us living in Atlantic Canada, maintaining adequate intake deserves some extra attention, particularly throughout the fall and winter months.

While supplementation isn’t a replacement for a balanced diet, regular movement, getting adjusted, strength training and healthy lifestyle habits, it can be a useful part of an overall wellness routine.

Sometimes, supporting your health starts with getting the basics right. Let us know if you have any questions about Vit D supplementation and we can help guide you.