Vitamin K: All you need to know

by | Jul 19, 2025 | General Knowledge, Vitamins

When it comes to essential nutrients, Vitamin K is often overshadowed by more well-known vitamins like D or C. But don’t let its low profile fool you. Vitamin K plays a crucial role in your body’s ability to clot blood, strengthen bones, and protect the heart. In this post, we’ll break down everything you need to know about this vital nutrient, including its types, benefits, sources, and how it works alongside other key vitamins.

What is vitamin K?

Vitamin K is a fat-soluble vitamin essential for several biological functions. The “K” comes from the German word Koagulation, highlighting its primary function in blood clotting. But beyond its role in preventing excessive bleeding, vitamin K also contributes to bone metabolism, calcium regulation, and cardiovascular health.

Vitamin K exists in two main forms:

  • Vitamin K1 (phylloquinone): Found primarily in green leafy vegetables.
  • Vitamin K2 (menaquinone): Found in fermented foods and animal products and produced by gut bacteria.

Each form serves similar functions but may work differently in the body. K2, in particular, is associated with more benefits for bone and heart health.

Health benefits of vitamin K

1. Blood clotting and wound healing

Vitamin K is a key player in producing proteins that allow blood to clot properly. Without it, even small cuts could lead to dangerous bleeding. According to the National Institutes of Health, deficiencies are rare but can occur in people with malabsorption conditions or those taking certain medications.

2. Stronger bones

Vitamin K supports the function of osteocalcin, a protein needed to bind calcium to bones. Research suggests that higher vitamin K intake is associated with greater bone density and a lower risk of fractures, especially in postmenopausal women.

3. Cardiovascular health

Vitamin K helps prevent calcification of the arteries, a process where calcium deposits build up in the blood vessels, potentially leading to heart disease. Vitamin K2 is especially effective in activating matrix GLA protein (MGP), which helps keep calcium in your bones and out of your arteries.

How much vitamin K do you need?

The recommended daily intake varies by age and gender, but for adults, it’s generally around:

  • Men: 120 micrograms/day
  • Women: 90 micrograms/day

These guidelines are mostly based on vitamin K1, as there’s no official RDA for K2 yet. However, many experts believe we may benefit from higher intakes of K2, especially for bone and heart health.

Top dietary sources of vitamin K

Vitamin K1-rich foods include:

  • Kale
  • Spinach
  • Collard greens
  • Broccoli
  • Brussels sprouts

Vitamin K2 can be found in:

  • Natto (a fermented soybean dish)
  • Hard and soft cheeses
  • Egg yolks
  • Liver
  • Chicken

Because it’s fat-soluble, vitamin K is better absorbed when consumed with healthy fats, just like vitamins A, D, and E, which we’ve covered in other posts on voltasante.com/blog.

Can you take too much?

Toxicity from vitamin K is extremely rare, especially from food sources. The body stores only small amounts, and excess is usually excreted. However, people on blood-thinning medications like warfarin should monitor their vitamin K intake closely, as it can interfere with the drug’s effects.

Vitamin K and supplement synergy

Vitamin K2 is often paired with vitamin D3 in supplements, especially those aimed at bone and heart health. This combo supports better calcium utilization. D3 helps with calcium absorption, while K2 ensures it goes to the right places.

The bottom line

Vitamin K may be small in quantity, but it’s mighty in function. From clotting your blood to fortifying your bones and protecting your arteries, this underrated vitamin deserves a place in your daily diet. Whether through leafy greens or fermented foods, or with the help of well-formulated supplements, getting enough vitamin K is an easy step toward stronger, healthier living.

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