Vitamin K supplements

Vitamin K is a fat-soluble vitamin that you primarily get from food, such as green vegetables. Your gut bacteria also produce this vitamin. 

But sometimes that is not enough and then supplements are a good addition.

This article will help you understand why vitamin K is important and when you need extra vitamin K.

What does vitamin K do for your body?

The main function of vitamin K is to support blood clotting, so that you do not lose too much blood in the event of an injury.

But it also contributes to the maintenance of strong bones. 

If you want to buy vitamin K supplements, it is good to know that there are 2 types of vitamin K.

What is the difference between vitamin K1 and K2?

Vitamin K comes in two major forms: K1, which is primarily found in food, and K2, which is primarily produced by intestinal bacteria.

These are the main differences between K1 and K2:

Vitamin K1

• Also called phylloquinone, phytomenadione or phylloquinone
• It is the form of vitamin K that is primarily involved in blood clotting
• If you eat enough green leafy vegetables such as spinach, kale and broccoli, you usually get enough vitamin K1

Vitamin K2

• Also called menaquinone
• Contributes to blood clotting, but is also good for strong bones (1)
• May also help keep blood vessels supple, which is good for the heart*
• Produced by your gut bacteria, it is also found in fermented foods such as natto (fermented soybeans), hard cheeses, and some animal products such as eggs

Vitamin K in nutritional supplements

Vitamin K supplements are available with only vitamin K1 or K2, but also as a combination (K1 + K2).

You can also choose between tablets or drops. Liquid vitamin K is especially useful for babies, children, and people who have difficulty swallowing tablets.

K1 supplements

Are you looking for vitamin K1?

Then phytomenadione is the primary and most commonly used form for vitamin K1 supplements.

This form is often chosen because it is effective in supporting healthy blood clotting and is easily processed by the body.

K2 supplements

If you want to supplement vitamin K2, the most common forms are MK-7 and MK-4.

The difference between MK-4 and MK-7 is in the length of the molecular chain and the origin, but both fall under the broader category of menaquinone (K2).

• MK-7 is a special form of vitamin K2 that is better absorbed by your body and remains active longer than other forms of vitamin K2 (2). This makes it an effective choice for supplementation, as it stays in your system longer and can thus better deliver its benefits.
• MK-4 is also commonly used in bone health supplements, but higher doses are needed to achieve long-lasting effects as it breaks down quickly.

In short: Choose the MK-7 variant if you're looking to buy a vitamin K2 supplement. This form is better absorbed by your body and remains active longer. There aren't many options for vitamin K1. Phytomenadione is the most commonly used and effective form.

Vitamin D and K

Vitamin K supplements are often combined with vitamin D because they complement each other. Together, these two vitamins play an important role in bone health.

• Vitamin D helps absorb calcium from food, but without enough vitamin K, this calcium may build up in unwanted places, such as your blood vessels.
• Vitamin K helps move calcium to your bones and not into your arteries, where it can clog blood vessels.

This type of combination is often recommended for people who have both vitamin D and vitamin K deficiencies.

Do I need extra vitamin K?

Adults (men and women) need 70 micrograms of vitamin K daily.

Although you can easily get vitamin K1 and K2 from your diet, some people may find it helpful to consider a supplement.

For example, if you:

1. You have a vitamin K deficiency, for example by not eating enough green vegetables.
2. Taking certain medications. Some medications, such as blood thinners, can prevent your blood from clotting, reducing the amount of vitamin K available. (3)
3. Taking antibiotics . These medications kill the good bacteria in your gut, which normally help make vitamin K. (3)
4. If you have certain conditions , such as osteoporosis, your bones may need extra support.
5. Are a woman and have (or have been) in menopause. A large-scale study of 16 different studies showed that women who had been in menopause and used vitamin K2 had a 57% lower risk of bone fractures compared to those who did not take vitamin K2. (1)

Note: If you are taking blood thinners or anticoagulants, always consult your doctor before taking a vitamin K supplement. Vitamin K can affect the way these medications work, making them less effective. Your doctor can advise you on whether it is safe to use vitamin K and, if so, the dosage.

Vitamin K for babies

Newborn babies do not yet have enough intestinal bacteria to produce the vitamin themselves and vitamin K is not passed on through the placenta.

That's why breastfed babies need extra vitamin K (150 micrograms per day) in the first three months. Special liquid vitamin K supplements are available for this purpose, which you can give to your baby in drops.

Please note : Formula usually contains sufficient vitamin K, but if a baby drinks less than 500 ml per day, additional vitamin K may be necessary.

What do I need, K1 or K2?

Whether you should buy vitamin K1 or K2 depends on your specific health situation and goals:

• K1 - Is ideal for supporting blood clotting.
• K2 - If you're interested in supporting your bones, vitamin K2 is an excellent choice.

Note : If you are unsure about which form of vitamin K you need, it may be helpful to discuss this with your doctor, especially if you are taking medications or have specific health conditions.

Sources used

1. Ma, M., Ma, Z., He, Y., Sun, H., Yang, B., Ruan, B., Zhan, W., Li, S., Dong, H., & Wang, Y. (2022). Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials. Frontiers in Public Health , 10 . https://doi.org/10.3389/fpubh.2022.979649
2. Sato, T., Schurgers, L. J., & Uenishi, K. (2012). Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women. Nutrition Journal , 11 (1). https://doi.org/10.1186/1475-2891-11-93
3. Yan, H., Chen, Y., Zhu, H., Huang, W., Cai, X., Li, D., Lv, Y., Si-Zhao, N., Zhou, H., Luo, F., Zhang, W., & Li, The Relationship Among Intestinal Bacteria, Vitamin K and Response of Vitamin K Antagonist: A Review of Evidence and Potential Mechanism. Frontiers in Medicine , 9 . https://doi.org/10.3389/fmed.2022.829304