When to take Vitamin K | PlanYourVitamins.com

What is vitamin K good for?

Short answer: Vitamin K has potential benefits for cardiovascular health, wound healing, bone health, brain health and mental health.

Vitamin K is actually a group of fat-soluble vitamins that are essential to human life, as they play a vital role in several aspects of our health, such as blood clotting, wound healing, tissue repair, bone health and cardiovascular health.

Vitamin K deficiency

Vitamin K deficiency can result in bleeding problems, and an increased risk of bone fractures, among many other complications. Our body is able to produce a small amount of vitamin K by itself, however it needs to obtain most of it via dietary intake, through foods such as leafy greens, fish, meat, liver and eggs.

The vitamin K group is divided into two main forms, which are called vitamin K1 and vitamin K2.

Vitamin K1 & vitamin K2

Vitamin K1, also known as phylloquinone, is the primary form of dietary vitamin K, and is especially present in leafy greens such as collard greens, kale and spinach.

Vitamin K2, also known as menaquinone, is found mainly in animal-sourced foods, as well as some fermented foods, and it is also the type of vitamin K that our gut bacteria is able to produce in small amounts naturally.

Vitamin K2 is in turn divided into several subtypes, with the two most common being menaquinone-4, or MK-4, and menaquinone-7, or MK-7. This level of granularity can be an important factor in certain aspects of our health, which is why some vitamin K2 supplements specify the subtype, although MK-7 is generally the preferred form, as it has a longer half-life, increasing its bioavailability.

Role in blood clotting

As mentioned above, vitamin K is critical for proper blood clotting, as it is required to make 4 of the 13 proteins that are required for blood clots to form, a crucial first step in wound repair, without which we would quite literally bleed to death.

In fact, the name "K" in vitamin K comes from the German word "Koagulationsvitamin", quite literally "coagulation vitamin", as this is how it was presented for the first time in a German scientific journal shortly after it was discovered. I bet you didn't know that!

Vitamin K plays a crucial role in the process of blood clotting and wound repair.

Role in bone health

Vitamin K's role in our bone health is due to its role in osteocalcin production, which ensures healthy bone density. Studies have been able to confirm that vitamin K deficiency is associated with increased risk of conditions such as osteoporosis and osteopenia.

Vitamin K also works together with vitamin D to distribute calcium properly throughout the body, and the two are often supplemented together to promote bone health for this purpose. More on that later.

Role in mental health

In addition to our physical health, vitamin K also appears to play an important role in our mental health. For example, one study involving older adults found that those with the highest levels of vitamin K in their blood also achieved the highest scores in verbal episodic memory performance.

When should I take vitamin K?

Short answer: Vitamin K is best taken with a meal, at any time of day, preferably including fatty foods (fish, meat, eggs, dairy, avocado, olive oil, nuts, seeds).

There is no specific time of day that appears to be best suited for taking vitamin K, however it is a fat-soluble vitamin, which means that in order for your body to properly absorb vitamin K supplements, they should be taken in combination with a meal, ideally one that contains dietary fat.

What does vitamin K combine well with?

Short answer: Vitamin K has been shown to work well together with vitamin D.

Vitamin K with vitamin D, for calcium distribution & bone health

As mentioned above, vitamin K and vitamin D are known to work as a team that benefits bone health, and research has demonstrated that taking a combination of both supplements, specifically vitamin D3 and vitamin K2, can significantly increase total bone mineral density.

Vitamin D is tasked with helping the body absorb calcium properly and ensuring that there are sufficient calcium levels in the blood, while vitamin K2 is tasked with transporting the calcium to where it is needed, such as in the bones and teeth, instead of allowing it to be deposited in dangerous places, such as in your artery walls.

This means that not only are vitamin K and vitamin D responsible for optimal bone health, but they benefit cardiovascular health too. Sadly, deficiencies in both of these vitamins are fairly common.

What should I avoid taking vitamin K with?

Short answer: Avoid taking vitamin K supplements at the same time as vitamin E or blood thinners.

Avoid with vitamin E

Vitamin K's effects could be reduced when taken in combination with vitamin E, due to the former being conductive towards blood clotting, while the latter is known to have a blood-thinning effect. It is advised to take them at least two hours apart in order to avoid them interfering with each other.

This conflict between vitamin K's coagulant and vitamin E's anticoagulant mechanisms can be especially problematic for people who have been prescribed vitamin K supplementation explicitly for the purpose of assisting with blood clotting.

Avoid with blood-thinning medication

Vitamin K's role in blood clotting means that it can have a serious and potentially dangerous interaction with anticoagulant or blood-thinning medication, so it is advised to avoid combining vitamin K with any such drugs.

What are natural sources of vitamin K?

If you are interested in achieving your daily vitamin K intake through your diet, rich sources of vitamin K include:

Leafy greens
Soybeans
Kiwis
Prunes
Avocados
Eggs
Chicken

Vitamin K data sources & further reading

Last updated by Asklepios on 30th January, 2025