WhyNotNatural Dietary Supplement: D3-K2 with Coconut MCT Oil, organic peppermint flavor

Combining Vitamin D3 and K2: Top Benefits Explained for Optimal Health

Are you looking to boost your overall health? Combining vitamin D3 and K2 might be the magical combination you need. 

Vitamin D3 is vital in calcium absorption, muscle strength, nerve communication, and immune system regulation. Vitamin K2, on the other hand, prevents calcium build-up in your arteries and ensures it goes straight to your bones where it’s needed most.

These vitamins are powerful for optimal skeletal and cardiovascular health. They work synergistically to enhance bone density, prevent heart disease, and regulate your mood and energy levels. The benefits are vast and impactful, from boosting serotonin to reducing the risk of certain cancers.

In this article, discover how these two essential vitamins can transform your health, the food sources for both, and the best ways to take them. 

Overview of vitamin D3

Vitamin D3, also known as the sunshine vitamin, is essential for many body functions, most importantly, calcium absorption and bone health. Below, we cover vitamin D3 in detail. 

What is the role of vitamin D3 in the body?

Vitamin D plays four core functions in the human body: calcium absorption and bone growth, muscle strength, nerve communication, and immune system modulation. 

Additionally, many studies show a strong correlation between normal vitamin D levels and certain medical conditions. There are many reasons to add vitamin D to your supplement regime. 

Let’s examine the role in detail. 

Calcium absorption and bone health

Calcium and phosphorus are two major building blocks of healthy bones and teeth. When combined, they create calcium phosphate, which hardens and strengthens bone.

The bone-building process requires the body first to absorb calcium and phosphorus from food sources and then for bone mineralization. 

Vitamin D plays an integral part in these two processes. Additionally, the body requires calcium for continued bone strength and maintaining bone mineral density. This is especially important for older adults, protecting them from osteoporosis. 

Osteoporosis increases the risk of fracture. It typically develops when the bone does not receive enough calcium, either through vitamin D deficiency or through lack of calcium. 

Muscle strength and movement

There’s also strong evidence that vitamin D supports muscle thickness and, thus, strength. Thicker skeletal muscles are more likely to be stronger and able to prevent falls.

A peek into the skeletal muscles of adults suffering from vitamin D deficiency showed a significant decline in predominantly type II muscle fibers. Type II muscles are essential for preventing falls. 

Research shows that vitamin D supplementation increased the average diameter of type II muscle fibers and the total number of type II fibers present. 

Enables nerve communication

The brain and the body are constantly exchanging information. From the retina, which informs the brain that it’s day or night, to ghrelin and leptin, which inform the brain that it’s time to eat or stop eating. 

This information passes through the nerves of the central nervous system. Vitamin D is essential for this process, as it is energy for nerves to carry messages between the brain and body

Research has shown that vitamin D level is correlated with nerve fiber density. The lower the vitamin D levels, the less dense the nerve fibers are, compromising the ability of the nerves to communicate with other nerves and, consequently, the brain. 

Immune system regulation

Vitamin D also benefits your innate immunity and ability to fight off bacteria and viruses. Innate immunity refers to your body’s first line of defense against invading pathogens. 

It’s no wonder research shows that those with high levels of vitamin D or its receptors are more likely to be naturally resistant to HIV-1 infection

Researchers have also observed that participants given vitamin D supplements were significantly less likely to get type A influenza. 

Boosts serotonin levels

Serotonin plays many important roles in the body. It helps control mood, regulate sleep patterns, and manage sexual desire. 

Studies show that having enough vitamin D can increase serotonin levels in the brain. This means that if you don't get enough vitamin D, you might feel moody and be at higher risk for mood disorders.

The National Institute of Mental Health (NIMH) says that having a vitamin D deficiency can make seasonal affective disorder (SAD) worse

This is because vitamin D is essential for producing serotonin, and low serotonin levels are a significant cause of SAD. 

Reduces cancer risk

Some scientific evidence suggests an association between the levels of vitamin D in the body and the risk of some cancers, although it's inconclusive. A study on colon cancer found that higher vitamin D levels can protect against the disease

More colon cancer deaths were observed in people living at higher altitudes, where UVB rays are weaker, and vitamin D production is lower. Other studies show that higher vitamin D levels are associated with reduced colorectal cancer risks

Research also indicates that vitamin D can improve cancer survival rates, with a 13% lower death rate in patients taking vitamin D supplements than those given a placebo.

Cell growth and differentiation

More recent research has shown that tissues and cells in regions like the breast and prostate contain vitamin D receptors (VDR). Multiple studies “indicate that this process may regulate cell growth and differentiation.” 

In simple terms, cell differentiation is how cells change their structure to take on a more specialized role in the body. 

For example, white and red blood cells have specialized roles in fighting invading pathogens and carrying oxygen around the body from the lungs, respectively. 

What are the sources of vitamin D3?

Three sources of vitamin D3 include:  


Image of a paper sun showing that it is a source of vitamin D

Exposure to the sun turns 7-dehydrocholesterol in the skin to pre-vitamin D3 and subsequently to vitamin D3. Although the sun is readily available, certain factors influence how much vitamin D your body can synthesize from it. Let's explore some key factors that can impact your vitamin D synthesis:

  • Dark skin: According to the CDC, non-Hispanic whites have higher levels of 25(OH)D than Mexican Americans, who in turn have higher levels than non-Hispanic Blacks. This is partly because melanin in darker skin reduces the body's ability to produce vitamin D from sunlight.
  • Older adults: People's ability to produce vitamin D from the sun wanes as they age.  This is why experts recommend that adults up to 70 take at least 600 IU of Vitamin D. Also, older adults, especially those with declining health, have reduced mobility and may spend more time indoors, leading to less sun exposure.
  • Altitude: People living at high altitudes are more likely to synthesize little vitamin D from the sun.  A study on sunlight exposure found that someone in Miami (2 meters above sea level) needs just three minutes in the sun to get enough vitamin D for the day. In comparison, someone in Boston (100 meters above sea level) needs 23 minutes.
  • Lifestyle choices: Lifestyle habits also contribute to how much vitamin D you can get from the sun.  For example, people who wear overalls and cover most of their bodies due to cultural or religious reasons will likely not synthesize enough vitamin D even if they spend quality time in the sun.  People who apply sunscreen may also not get enough vitamin D because of the added protective layer.  

Food sources

Various foods rich in vitamin D, such as fish, eggs, milk, and cheese, displayed on a table.Various foods rich in vitamin D, such as fish, eggs, milk, and cheese, displayed on a table.

Few foods naturally provide abundant vitamin D. Foods rich in vitamin D include fatty fish like tuna and salmon and fish liver oils. Other foods contain only small amounts. 

Due to limited natural sources of vitamin D, many foods are fortified with it. In the United States, milk is often fortified with 120 IU of vitamin D3 per cup. Cereals and fruit juices are other sources. 

Dietary supplements

Dietary supplements are also a viable way to meet the daily recommended allowance of vitamin D. There are organic vitamin D supplements made with clean, vegan-friendly ingredients, like Why Not Natural’s D3+K2 combination. 

What should I avoid when taking vitamin D3?

While taking any vitamin D supplement, you want to avoid taking high doses of calcium supplements, especially without medical advice. 

Although both work together to maintain bone health, too much calcium may lead to hypercalcemia, a condition with symptoms like nausea, vomiting, weakness, and severe kidney problems like renal failure. Additionally, excess calcium in the blood can deposit—and clog—the arteries. 

Alcohol consumption can interfere with the liver's ability to convert vitamin D into its active form, leading to limited absorption. 

Lastly, certain medications can reduce the absorption rate of vitamin D, including steroids like prednisone, diltiazem and weight-loss drugs like Orlistat. 

What is the key difference between vitamin D and vitamin D3?

Vitamin D3 is a vitamin D variant. The most common variants of vitamin D are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). 

The primary difference between the two is that D2 is from plant-based foods like mushrooms, and D3 is from animal-based foods like liver and eggs. D3 is the vitamin D the body produces from sun exposure. Both forms are available in dietary supplements. 

Research also shows that vitamin D3 is superior to vitamin D2 in restoring a person’s severe vitamin D deficiency. 

Overview of vitamin K2

Vitamin K2, also known as menaquinone, is a form of vitamin K. Below, we examine its role in the body and share other important information about it. 

What is the role of vitamin K2 in the body?

Vitamin K2 has two primary functions in the body, including:

Prevents calcification of blood vessels

Vitamin K2 is very active in the blood vessels, initiating the Matrix Gla-protein (MGP) protein. MGP is one of the vitamin K-dependent proteins; that is, it needs the vitamin for activation. Its primary function is to inhibit calcification in the arteries. 

Consider vitamin K2 as the command center that deploys police, in this case, MGP, to clear excess calcium lining the blood vessels. MGP's ability to clear the blood vessels is tied to its high affinity for binding to calcium ions. 

As such, the activities of the MGP help reduce the risk of heart disease. 

Aids bone tissue formation

Osteocalcin is a protein that helps draw calcium from the blood and deposit it in the bone tissues, ensuring proper bone mineralization. Osteoblasts produce osteocalcin; however, vitamin K2 activates the protein. 

Due to osteocalcin’s role in bone health, doctors use it “as a serum marker of osteoblastic bone formation.” This means that the osteocalcin level shows osteoblasts’ activity, that is, how active osteoblasts are in forming new bone tissues.

When the osteoblasts are working properly, bones maintain their density and prevent issues like osteoporosis, a condition characterized by soft bones. 

What are the sources of vitamin K2?

Foods rich in vitamin K2 are rare. You’ll typically find K2 in fermented and animal-based foods. Fermented foods like fermented soybeans (Natto), yogurt, and certain cheeses are some of the best sources of vitamin K2. Chicken liver, egg yolks, beef, pork, salmon, and organ meats are rich in vitamin K2. 

Also, gut bacteria in the large intestine produce some vitamin K2. However, the volume produced may not meet the body’s needs.

Interestingly, the body also converts some vitamin K1 to K2. However, the process is fraught with many challenges. First, only 10-15% of vitamin K intake from food sources is absorbed in the gut. 

Additionally, the conversion process doesn’t yield enough K2 that your body needs, hence the need to get K2 from other sources like food and supplements

What should I avoid when taking vitamin K2?

Vitamin K2 disrupts the effects of blood thinning medication, warfarin. So, if you’re on warfarin or other blood thinners, avoid taking vitamin K2 to prevent heart attack, stroke, or blood vessel blockages. 

Furthermore, drugs like cholesterol-lowering medications, weight-loss medications, phenytoin, and antibiotics like cefamandole, cefoperazone, and cefmetazole reduce the body’s ability to absorb or prevent the body from using vitamin K2. 

Can vitamin K2 help clear arteries?

Vitamin K2 activates Matrix Gla-protein (MGP), which helps clear the arteries of only calcium deposits. It does this by binding to the calcium deposits and moving them from the lining of the blood vessels.

However, there is no substantial evidence that vitamin K2 helps clear other elements like fat and cholesterol from the arteries. 

Does vitamin K2 reduce cholesterol levels?

Vitamin K2’s primary roles in the body are related to bone and cardiovascular health, particularly in regulating calcium deposition. Emerging research suggests that vitamin K2 may affect cholesterol levels; however, this evidence is not conclusive. 

Moreover, the bulk of the evidence comes from animal studies. For example, a study targeting eight rabbits showed that “the pharmacological dose of vitamin K2 prevents both the progression of atherosclerosis and the coagulative tendency by reducing the total cholesterol in hypercholesterolemic rabbits.” 

Only a few human studies have explored this potential effect. Some studies indicate that vitamin K2 might have a beneficial impact on cholesterol levels. Still, these findings are only consistent across some studies. As such, more evidence is needed to confirm that vitamin K2 can help reduce cholesterol levels.

Is vitamin K2 safe for kidney health?

Vitamin K2 is generally safe for kidney health in normal, healthy individuals. However, backed by research, healthcare professionals urge caution for those receiving dialysis for kidney disease.

As a matter of fact, the risk of suffering any side effects or toxicity while taking vitamin K2 supplements is very slim. That’s why no published Tolerable Upper Intake Level (UL) set for the vitamin exists.

The only major caution is to avoid taking vitamin K2 with warfarin, as vitamin K2 may counteract the drug’s effect, leading to more blood clots. If you must use vitamin K2, your doctors may need to change your warfarin dose. 

Can vitamin K2 lower blood pressure?

Vitamin K2 has an indirect effect on blood pressure. The vitamin activates a protein, the Matrix Gla-protein (MGP), that clears the arteries of calcium deposits. By preventing artery calcification, vitamin K2 ensures that blood continues to flow freely without built-up pressure from clogged arteries. 

Research supports this notion. In a population-based study, researchers found that consuming at least 32 mcg of vitamin K2 daily “resulted in 50 percent reduction of arterial calcification, 50 percent reduction of cardiovascular risk, and 25 percent reduction of all-cause mortality.” 

What are the benefits of combining vitamin D3 and K2?

Using vitamin D3 and K2 separately offers tremendous health benefits. However, the two together are like a superpower, especially regarding bone health. The benefits include: 

Promotes supreme bone health

Vitamins D and K2 work synergistically with calcium to ensure optimal bone strength and density. Vitamin D absorbs calcium from food in the small intestine. Calcium can be a bit tough for the body to absorb, but optimal vitamin D in the blood makes it possible. 

Additionally, the body needs calcium for other bodily functions beyond bone health. If you’re not consuming enough calcium from your diet or your body is not absorbing enough calcium due to vitamin D deficiency, the body pulls calcium from the bones. 

That’s unhealthy, as continuous retrieval of calcium from the bones reduces its strength and density, making it more prone to fracture and deformity. So, vitamin D ensures your body absorbs enough calcium and “signals” to the brain that there’s adequate calcium in the blood and no need to take it from the bones. 

Vitamin K2 complements vitamin D’s work by ensuring the absorbed calcium is used well. With vitamin D flowing sufficiently in the bloodstream, vitamin K2 is the tool to route the calcium from the blood to the bone tissues. 

To emphasize the synergy between and need for these two vitamins, researchers analyzed 80 studies. They concluded that “Current evidence supports the notion that joint supplementation of vitamins D and K might be more effective than the consumption of either alone for bone and cardiovascular health.” 

Research also shows that taking vitamins K and D together creates new osteoblasts, cells tasked with creating bone tissues. 

Helps remove excess calcium from the blood vessels to prevent heart attacks

Heart disease is the leading cause of death annually in the United States. One of the leading causes of heart-related issues is plaque or deposit buildup in the arteries, known as atherosclerosis. 

Calcium, fat, and cholesterol make up the bulk of plaque constitution. This makes calcium deposits in the arteries a big concern for heart disease. Vitamin K2 activates a protein known as Matrix Gla-protein that mops up calcium from the blood vessels. 

Without this protein, plaque will build up faster in the arteries. This can affect your blood pressure, but it is more dangerous because the plaque can break loose and cause total blockage of a blood vessel. Such a situation leads to a heart attack if the blockage happens in a significant vessel supplying blood to the heart. 

So, vitamin D with vitamin K supplementation leads to less calcium lining the walls of your blood vessels and better overall cardiovascular health. 

May help fight diabetes

Researchers explored the effect of vitamin K2 on insulin sensitivity and found that the vitamin improved this key metric

Insulin sensitivity measures how the cells in the body respond to insulin. The cells should respond to insulin rather than be resistant. Insulin resistance leads to diabetes. Furthermore, the researchers concluded that vitamin K2 had a better effect than vitamin K1 on type 2 diabetes mellitus (T2DM). 

In another study, researchers noted that joint vitamin K2 and D3 supplementation significantly reduced blood glucose levels. 

How do I take a combination of vitamin D3 and K2?

The easiest way to combine vitamin D3 and K2 is by getting a supplement that already contains both, like the Organic Vitamin D3 Liquid Drops with K2 (MK-7) from Why Not Natural. 

Doing so has many benefits, including ease of use and remembering to use the two daily. Moreover, the Organic Vitamin D3 Liquid Drops with K2 (MK-7) from Why Not Natural comes with a dropper that makes dosing very easy. 

For example, every drop contains 200 IU of vitamin D3 and four mcg of vitamin K2. 

What is the recommended dosage of vitamin D3 and K2?

The recommended dosage of vitamin D3 varies based on age, health status, and individual needs. 

Here are the general guidelines for vitamin D3:

  • Infants (0-12 months): 400 IU (10 mcg) per day
  • Children (1-18 years): 600 (15 mcg) per day
  • Adults (19-70 years): 600 IU (15 mcg) per day
  • Older Adults (71+ years): 800 IU (20 mcg) per day
  • Pregnant and Breastfeeding Women: 600 (15 mcg) per day

For individuals suffering from vitamin D deficiency (< 30 nmol/L or 12 ng/mL), their dosing is usually different. 

Doctors often recommend very high dosages, ranging from 2,000 IU to 5,000 IU daily, in the first few weeks to attain normal vitamin D levels before reducing the dose.  

There are no specific RDA values for vitamin K2. Here are the general guidelines for vitamin K, which is inclusive of K1, K2, and other forms of vitamin K: 

  • Infants (0-6 months): 2 mcg per day
  • Infants (7-12 months): 2.5 mcg per day
  • Children (1-3 years): 30 mcg per day
  • Children (4-8 years): 55 mcg per day
  • Children (9-13 years): 60 mcg per day
  • Children (14-18 years): 75 mcg per day
  • Adults (19+): 120 mcg for males and 90 mcg daily for females 

Maintaining these RDA intakes will help avoid vitamin K deficiency, including vitamin K2. 

Is it better to take vitamin D3 and K2 in the morning or at night?

You can take vitamin D3 and K2 any time of the day. However, some experts recommend taking them in the morning, mainly because of vitamin D3. If we're relying on the sun, we should ideally generate a bulk of our vitamin D3 in the morning-noon period. 

There are concerns that taking vitamin D at night can interfere with melatonin production, but there is no concrete evidence to support this yet. 

That said, decide on a time you can consistently remember. Establishing a routine, whether in the morning or evening, helps ensure you take appropriate doses. 

Lastly, observe how your body reacts to taking these vitamins. If you find that taking them at night disrupts your sleep pattern, then taking them in the morning might be better for you. 

Who should avoid taking vitamin D3 and K2?

For starters, anyone diagnosed with hypercalcemia should avoid taking vitamin D3 and K2. Hypercalcemia is a condition where calcium levels in the blood are above average. Taking vitamin D3 and K2 can increase calcium absorption, potentially worsening hypercalcemia. 

Also, vitamin K may disrupt the actions of blood thinners like warfarin. Similarly, those suffering from kidney conditions should consult a healthcare professional before taking vitamin D3 and K2. 

Our general recommendation is that anyone with underlying health conditions should consult with a healthcare provider before starting vitamin D3 or K2 supplements or any supplements.

Can I take vitamin D3 without K2?

You can take vitamin D3 without K2 and vice versa. While vitamin D3 and K2 work synergistically in some aspects, particularly in regulating calcium metabolism, they can still be taken independently, depending on your specific health needs and dietary intake.

Taking the two together, however, provides some form of balance. Vitamin K2 ensures that the calcium absorbed through the help of vitamin D3 is put to good use. Vitamin K2 also ensures there are fewer calcium deposits in the blood vessels.

Can I take vitamin D3 and K2 on an empty stomach?

Although taking vitamin D3 and K2 on an empty stomach has no adverse effects per se, we strongly advise against it. An empty stomach can reduce how well these vitamins are absorbed. 

Both vitamin D3 and K2 are fat-soluble, so taking them with a meal that includes fat can enhance absorption. Some meals to consider include eggs, cheese, olive oil, nuts, fatty fish, and more.

Is it possible to have an excessive amount of Vitamin D3 or Vitamin K?

It’s possible to have an excess of any vitamin, especially if you consistently and continuously take a very high dosage beyond the safe upper intake level for a long time. 

The safe upper intake level for most adults is set at 4,000 IU per day for vitamin D. However, toxicity typically occurs at much higher doses, often above 10,000 IU per day for an extended period.

Your serum vitamin D level will likely jump to 100 ng/mL and above when this happens. Such high levels are described as hypervitaminosis D. 

Symptoms of hypervitaminosis D include constipation, dehydration, fatigue, loss of appetite, urinary calcium excretion, hypercalcemia, and more. 

As for vitamin K2, there’s really no ballpark to describe excessive amounts. Scientists are still figuring out how to categorize different vitamin K status. 

Manage your dosage properly with Why Not Natural D3+K2 liquid drops. It comes with a dropper for easy dosage. Every drop of the vitamin combo contains 200 IU of vitamin D3 and four mcg of vitamin K2.

Do vitamin D3 and K2 have side effects?

Both vitamin D3 and K2 are generally safe and well-tolerated when taken within recommended dosages. However, different individuals may react to them differently. For example, some people report having stomach upset after vitamin K2 supplementation. 

For the most part, sticking to the recommended daily allowance will help you avoid most potential side effects. 

Takeaway: Embrace the power of vitamin D3 and K2 for optimal health

WhyNotNatural Dietary Supplement: D3-K2 with Coconut MCT Oil, organic peppermint flavor

Combining vitamin D3 and K2 is a powerful way to enhance your health. These vitamins work together to support bone strength, prevent heart disease, and boost your immune system. 

Whether you aim to improve muscle strength, enhance nerve function, or maintain overall wellness, adding these vitamins to your routine can make a big difference. 

Remember to take them with meals containing fat for better absorption, and consult with your healthcare provider if you have any underlying health conditions. 

Get vitamin D3 and K2 combined today from Why Not Natural. This combination is made with organic ingredients, contains no fillers, and is vegan and vegetarian-friendly.

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