Where is Vitamin K1 Mostly Obtained from? Your Guide to Phylloquinone Sources

October 30, 2025 •

5 min read

Vitamin K is a vital, fat-soluble nutrient, and phylloquinone, or vitamin K1, is the primary dietary form, making up 75% to 90% of our intake. If you're wondering where is vitamin K1 mostly obtained from? the answer lies predominantly in a variety of nutrient-dense, green plant foods. This guide explores the richest dietary sources of this crucial compound and why a consistent intake is important for your health.

Quick Summary

This guide details the primary sources of vitamin K1, also known as phylloquinone, which is most abundantly found in dark, leafy green vegetables. It also identifies other plant-based sources like vegetable oils, certain fruits, and specific herbs that contribute to a healthy diet.

Key Points

Richness in Leafy Greens: Dark, leafy green vegetables such as kale, spinach, and collard greens are the most concentrated dietary source of vitamin K1 (phylloquinone).
Fat for Absorption: As a fat-soluble vitamin, K1 is better absorbed when consumed with a source of fat, such as the dressing on a salad or oil in cooked dishes.
K1 vs K2 Sources: Vitamin K1 comes mainly from plants, while vitamin K2 is sourced primarily from animal products and fermented foods like natto.
Essential for Blood Clotting: The most important function of vitamin K1 is its role as a cofactor in producing proteins necessary for blood coagulation.
Supports Bone Health: Beyond clotting, vitamin K1 also contributes to bone health by helping to mineralize bones and potentially lowering the risk of fractures.
Warfarin Interaction: Individuals on blood-thinning medication like warfarin must maintain a consistent vitamin K1 intake to avoid interference with the drug's effectiveness.

Understanding the Forms of Vitamin K

Vitamin K is not a single compound but a group of structurally similar, fat-soluble vitamins. The two most significant forms in human nutrition are Vitamin K1 and Vitamin K2.

Vitamin K1 (Phylloquinone): This is the most common form in the diet and is found primarily in plant foods. Its name, derived from the Greek for "leaf," reflects its high concentration in green, leafy vegetables, where it plays a role in photosynthesis.
Vitamin K2 (Menaquinones): This form consists of a family of compounds (menaquinones) that are mostly found in animal-based and fermented foods, like natto and certain cheeses. It is also produced by bacteria in the large intestine, which can also convert some K1 into K2.

While both forms are crucial, they differ in their primary dietary sources and absorption pathways, underscoring the importance of consuming both plant and animal-based foods for a complete nutritional profile.

The Richest Plant Sources of Vitamin K1

When it comes to answering where is vitamin K1 mostly obtained from?, the definitive answer is dark, leafy green vegetables. These plants are true nutritional powerhouses, providing exceptionally high amounts of phylloquinone. Consuming these vegetables, especially with a little oil, can significantly increase the vitamin's absorption since it is fat-soluble.

Top-Tier Leafy Greens

Cooked Kale: A true superstar, with one cup of cooked kale providing a massive 1,062 micrograms, which is well over the recommended daily intake for adults.
Raw Swiss Chard: With 830 micrograms per 100 grams, Swiss chard is another excellent source that can be easily added to salads and other dishes.
Mustard Greens: Just a half-cup of cooked mustard greens delivers a potent 415 micrograms, far exceeding the daily value.
Collard Greens: Whether raw or cooked, collard greens are a rich source, packing 623 micrograms per 100 grams when cooked.
Spinach: A staple in many diets, raw spinach offers 145 micrograms per cup, making it a reliable source for salads and smoothies.
Turnip and Beet Greens: Both are strong contenders, providing over 480 micrograms per 100 grams when cooked.

Beyond Leafy Greens: Other Notable Sources

While greens dominate, other plant foods also provide valuable amounts of vitamin K1.

Vegetable Oils: Oils made from soybeans and canola are significant contributors to K1 intake. One tablespoon of soybean oil can provide a notable amount of phylloquinone.
Cruciferous Vegetables: Broccoli, Brussels sprouts, and cabbage are all good sources of vitamin K1. A half-cup of cooked Brussels sprouts contains 109 mcg, while broccoli provides 110 mcg per half-cup.
Certain Fruits: While not as concentrated as leafy greens, some fruits can contribute. These include kiwi, blueberries, and grapes.
Legumes and Nuts: Some varieties, like pine nuts and cashews, contain decent amounts of K1, though significantly less than green vegetables.
Dried Herbs: Herbs such as dried basil, thyme, and parsley contain extremely high levels of vitamin K1 by weight, though they are consumed in smaller quantities.

Comparison of Vitamin K1 and K2 Sources

To better understand the differences, here is a comparison table outlining the main sources for each vitamin K type.


Feature	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinones)
Primary Sources	Green leafy vegetables, plant oils, some fruits and legumes	Fermented foods (natto), animal products (meat, eggs, cheese)
Primary Role	Blood clotting (activation of clotting factors in the liver)	Bone metabolism, cardiovascular health (regulates calcium binding)
Synthesized By	Plants during photosynthesis	Bacteria in the gut flora and via conversion of K1 in the body
Bioavailability	Lower than K2 from food, but enhanced with dietary fat	Higher absorption rate, depends on type (MK-7 vs MK-4)
Storage	Less efficient storage; primarily used by the liver	Longer-term storage, more efficiently distributed to extrahepatic tissues

The Function and Importance of Vitamin K1

Vitamin K1 is not just a trace nutrient; it is essential for several critical bodily functions. The most well-known is its role in blood coagulation. The 'K' in its name comes from the German word Koagulation, highlighting its function in helping blood clot properly. It acts as a cofactor for enzymes that produce specific proteins in the liver, known as Gla-proteins, which are necessary for blood clotting. Without adequate K1, this process is impaired, leading to excessive bleeding and easy bruising.

Beyond coagulation, vitamin K1 is also involved in promoting bone health. It assists in the carboxylation of osteocalcin, a protein that plays a key role in bone mineralization. While the link between K1 intake and bone health is still being researched, some studies suggest higher intake correlates with better bone mineral density.

Potential Risks and Considerations

While it is extremely rare to consume too much vitamin K1 from food alone, individuals on certain medications, particularly the blood-thinner warfarin (Coumadin), must carefully manage their intake. Vitamin K directly counteracts the effects of warfarin, so maintaining a consistent daily intake is crucial for therapeutic stability. Any major changes in dietary K1 should be discussed with a healthcare provider.

Conclusion: Incorporating Vitamin K1 into Your Diet

For most healthy adults, meeting the daily recommendation for vitamin K1 is easily achievable through a balanced diet rich in plant-based foods. As the primary dietary source of phylloquinone, dark, leafy green vegetables like kale, spinach, and collard greens are the most effective way to ensure a sufficient intake. Including these in meals alongside a source of fat, like olive oil in a salad dressing, can further enhance absorption. By prioritizing these vibrant greens, you can support your body's essential blood clotting mechanisms and contribute to long-term bone health through natural, whole food sources.

How to get the most from plant-based K1

To maximize your body's utilization of vitamin K1 from plant sources, consider pairing them with a healthy fat. Because vitamin K is fat-soluble, consuming it with oils or other fat-rich foods significantly boosts its absorption. Drizzling a vinaigrette over a spinach salad or sauteing kale in olive oil are simple strategies to enhance your intake. For those on blood-thinning medication, maintaining a consistent amount of K1 in your diet is more important than avoiding it entirely. Regular communication with your doctor about your dietary habits is the best approach to managing your intake effectively.

Frequently Asked Questions

Vitamin K1 (phylloquinone) is mainly found in plant foods, especially leafy green vegetables. Vitamin K2 (menaquinones) is found in fermented foods, some animal products like eggs and dairy, and is also produced by gut bacteria.

No, while leafy greens are the richest source, vitamin K1 is also found in other vegetables like broccoli and Brussels sprouts, some vegetable oils (soybean, canola), and certain fruits such as kiwi and blueberries.

Cooking can sometimes concentrate vitamin K1 by reducing water content, potentially increasing its presence per serving. However, the fat-soluble nature of the vitamin means that cooking with oil is the most effective way to boost its absorption.

Clinical vitamin K deficiency is rare in healthy adults who consume a varied diet. It is most commonly seen in newborn infants, who are typically given an injection at birth, and in individuals with malabsorption disorders or those taking certain medications.

To improve absorption, consume vitamin K1-rich foods with a source of dietary fat. Since it is a fat-soluble vitamin, combining it with healthy fats, like the oil in a salad dressing or avocado, significantly enhances its bioavailability.

It is extremely rare to get a harmful excess of vitamin K1 from dietary sources alone. The body effectively regulates its use. However, individuals taking blood thinners must monitor their intake carefully to maintain therapeutic consistency.

Symptoms of severe deficiency include easy bruising, excessive bleeding from wounds or gums, blood in the urine or stool, and an increased risk of bone fractures and osteoporosis.