Does Kale Have K1 or K2? Understanding the Vitamin K in Your Greens

January 3, 2026 •

4 min read

A single cup of cooked kale can provide over 10 times the daily recommended dose of vitamin K. The question many health-conscious consumers have, however, is whether this immense amount comes from vitamin K1 or K2.

Quick Summary

Kale is a nutritional powerhouse, but which type of vitamin K does it contain? This article clarifies that kale is a potent source of vitamin K1, while detailing the different functions and food sources of both vitamin K1 and K2.

Key Points

Kale is rich in Vitamin K1: The leafy green is a powerhouse of phylloquinone (K1), with one cup often exceeding the daily recommended value.
K1 primarily supports blood clotting: Kale's vitamin K1 content is crucial for activating proteins necessary for proper blood coagulation.
K2 is found in fermented and animal foods: The menaquinone form (K2) is primarily sourced from bacteria in fermented products like natto and from animal products like egg yolks and cheese.
Absorption is improved with fat: Since vitamin K is fat-soluble, consuming kale with healthy fats like olive oil or avocado can enhance your body's absorption of K1.
Both K1 and K2 are important: While kale provides K1, a balanced diet should also include K2 from other sources to support both blood and bone health.
The body makes some K2: Gut bacteria can produce small amounts of vitamin K2, but dietary intake from fermented foods and animal products is still beneficial.

The Distinction Between Vitamin K1 (Phylloquinone) and K2 (Menaquinone)

Before answering the question about kale, it is essential to understand the fundamental difference between the two primary forms of vitamin K. The term "vitamin K" actually refers to a group of fat-soluble vitamins with similar chemical structures. The two main types found in the human diet are vitamin K1 (phylloquinone) and vitamin K2 (menaquinone).

Vitamin K1 is produced by plants and is the most common form of vitamin K consumed in the human diet. Its name, "phylloquinone," is derived from the Greek word for 'leaf,' a fitting descriptor given its concentration in dark, leafy green vegetables. K1 is primarily involved in blood coagulation by activating proteins that help with blood clotting.

In contrast, vitamin K2 is a group of compounds called menaquinones, which are primarily produced by bacteria. They are found in certain animal products and fermented foods and are also synthesized by the healthy bacteria in your gut. Unlike K1, which mainly supports liver functions related to blood clotting, K2 is more known for its role in directing calcium to the bones and teeth, helping to prevent its buildup in the arteries.

Kale: A Champion of Vitamin K1

To put it simply, kale is one of the most concentrated food sources of vitamin K1, not K2. As a leafy green vegetable, its high phylloquinone content is what makes it such a nutritional powerhouse. A single cup of raw kale, for example, contains a very high amount of vitamin K1, while providing virtually no vitamin K2.

This high concentration of K1 is one of the main reasons kale is a staple in many healthy diets. Its role in supporting proper blood clotting is well-documented, making it an important food for overall cardiovascular health. For those taking blood-thinning medications like warfarin, the high and consistent K1 content in kale is a crucial consideration that must be managed with a healthcare professional.

Maximizing Vitamin K Absorption from Kale

Since vitamin K is a fat-soluble vitamin, combining kale with a source of dietary fat can significantly boost your body's absorption of the nutrient. Here are some practical ways to do this:

Add a healthy dressing: A salad with kale and an olive oil-based dressing is an excellent combination.
Sauté with oil: Cooking kale with a small amount of oil, such as olive or coconut oil, can increase its bioavailability.
Pair with avocado: Including sliced avocado in a kale salad not only adds a creamy texture but also provides healthy fats.
Include in a fatty meal: Pairing kale as a side dish with a meal that includes healthy fats like salmon or nuts can help with absorption.

K1 vs. K2: Understanding the Differences

While kale is predominantly a K1 source, a balanced diet should ideally include both forms of vitamin K. The body's utilization and functions of K1 and K2 differ, with K2 having unique benefits for bone density and cardiovascular health.


Feature	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinone)
Primary Source	Plant-based foods (leafy greens)	Animal products & fermented foods
Main Function	Blood clotting, liver functions	Calcium metabolism, bone health, cardiovascular health
Chemical Name	Phylloquinone	Menaquinones (MK-4, MK-7, etc.)
Best Food Sources	Kale, spinach, broccoli, collard greens	Natto, cheese, egg yolks, liver
Produced By	Plants	Bacteria (in fermented foods and gut)

The Role of Gut Bacteria and Fermented Foods

Small amounts of vitamin K2 are produced by the beneficial bacteria in your gut. However, relying solely on this internal production might not be enough to meet optimal levels. This is why incorporating specific fermented foods and animal products into your diet is beneficial.

Natto, a traditional Japanese dish made from fermented soybeans, is one of the richest known sources of K2, particularly the MK-7 subtype. Other fermented foods like sauerkraut and kefir also contain varying amounts of K2. Including these foods, alongside the K1-rich kale, can provide a more comprehensive vitamin K intake.

Conclusion: Kale's Place in Your Vitamin K Strategy

When it comes to the question of does kale have K1 or K2, the answer is overwhelmingly K1. Kale is an exceptional source of vitamin K1, offering substantial amounts to support healthy blood clotting. While it is not a significant source of vitamin K2, its role as a nutrient-dense food makes it a valuable addition to a balanced diet. To ensure you receive the benefits of both forms of this essential vitamin, it is best to combine a daily intake of leafy greens like kale with moderate consumption of K2-rich foods, such as fermented products and quality dairy or meat. A holistic approach that includes a variety of sources is the most effective way to meet your nutritional needs for both K1 and K2.

For more information on the different types of vitamin K and their food sources, visit the Harvard T.H. Chan School of Public Health's dedicated nutrition page.

Frequently Asked Questions

Yes, kale is an excellent source of vitamin K. Specifically, it contains a very high concentration of vitamin K1, or phylloquinone, which is crucial for blood clotting.

Vitamin K1 (phylloquinone) is found in plant foods and is important for blood coagulation. Vitamin K2 (menaquinones) is found in animal products and fermented foods, and it plays a vital role in calcium metabolism for bone and heart health.

Yes, all green leafy vegetables, including spinach, collard greens, and broccoli, are primary sources of vitamin K1.

To increase your intake of K2, you can eat fermented foods like natto or sauerkraut, as well as certain animal products such as liver, egg yolks, and specific cheeses.

Cooking can increase the bioavailability of vitamin K1 in kale, meaning your body may absorb it more efficiently, especially when cooked with a source of fat.

Yes, if you take blood-thinning medication like warfarin, you should consult a doctor or dietitian about your vitamin K intake, as large fluctuations can interfere with the medication's effectiveness.

While bacteria in your gut can convert some K1 into K2, the amount is usually insufficient for optimal levels. It is best to consume a variety of foods to ensure a good intake of both forms.