What Provides the Most Vitamin K? A Look at Top Food Sources

Over one-third of US adults consume less vitamin K than recommended, making it important to know where to find this essential nutrient. So, what provides the most vitamin K, and how can you ensure you're getting enough for optimal blood clotting and bone health?

Quick Summary

This guide details the highest food sources of both vitamin K1 and K2, with a special focus on standout examples like natto, collard greens, and kale. It explains the differences between the two forms and offers practical tips for incorporating them into your daily diet for maximum health benefits.

Key Points

• Top Sources: Fermented soybeans (natto) and cooked leafy greens like collard and turnip greens provide the highest concentrations of vitamin K.

• Two Types, Two Roles: Vitamin K1 is found in plants and primarily aids in blood clotting, while K2 comes from fermented and animal foods and supports bone and heart health.

• Cooking Increases Concentration: Cooking leafy greens often reduces their water content, which increases the amount of vitamin K per serving.

• Absorb with Fat: Because vitamin K is fat-soluble, eating it with dietary fat, like an oil-based dressing, can improve its absorption.

• Variety is Key: For comprehensive benefits, it is best to incorporate a mix of both K1-rich vegetables and K2-rich fermented foods and dairy into your diet.

Understanding the Two Types of Vitamin K

Before diving into the top food sources, it's essential to understand that vitamin K comes in two main forms: K1 (phylloquinone) and K2 (menaquinone). These two types differ in their sources and, to some extent, their roles in the body.

• Vitamin K1: Found predominantly in plant-based foods, especially dark leafy green vegetables. Its primary function is to support proper blood clotting.
• Vitamin K2: Found in animal products and fermented foods, and also produced by bacteria in the gut. While it also aids in blood clotting, it is more heavily involved in bone metabolism and preventing arterial calcification.

The Powerhouses of Vitamin K1: Leafy Greens

When it comes to vitamin K1, dark, leafy green vegetables are the undisputed champions. Cooking these vegetables often concentrates their vitamin K content by reducing water volume, providing an even higher dose per serving.

Here are some of the most potent vitamin K1 sources:

• Collard Greens: A single cup of boiled and drained collard greens contains well over 500 mcg of vitamin K, offering several times the daily recommended intake.
• Turnip Greens: Similar to collard greens, a half-cup of boiled turnip greens provides a substantial amount of vitamin K1.
• Kale: Whether raw or cooked, kale is a powerhouse of vitamin K. Just one cup of chopped kale offers more than enough for the entire day.
• Spinach: Raw spinach is also packed with vitamin K, delivering a significant portion of your daily needs in just one cup.
• Other notable mentions: Mustard greens, Swiss chard, and beet greens are also excellent sources.

Standout Sources of Vitamin K2

While K1 is abundant in plants, getting enough vitamin K2 requires a focus on specific animal and fermented foods. The content of K2 can vary, and research on its exact levels is ongoing.

• Natto: This traditional Japanese dish of fermented soybeans is hands-down the richest food source of vitamin K2, specifically menaquinone-7 (MK-7). A single serving can provide a massive dose of K2.
• Goose Liver: Among animal sources, goose liver is exceptionally high in K2.
• Cheeses: Hard and soft cheeses, like blue cheese and cheddar, can be a good source of vitamin K2, with concentrations varying by type.
• Eggs and Meats: Eggs (especially the yolk) and certain meats like chicken and organ meats contain K2, though in much smaller amounts than natto.

How Cooking Affects Vitamin K Content

Since vitamin K is a fat-soluble vitamin, combining these foods with a small amount of dietary fat (like olive oil) can enhance absorption. Interestingly, cooking methods can also influence concentration. For instance, boiling green vegetables removes some of their water, which concentrates the vitamins, including vitamin K.

Comparison of Top Vitamin K Sources

Food (per serving)	Vitamin K (mcg)	Form of Vitamin K	Notes
Natto (3 oz)	~850	K2 (MK-7)	Unbeatable fermented source.
Collard Greens (boiled, ½ cup)	~530	K1	Concentrated by cooking.
Turnip Greens (boiled, ½ cup)	~426	K1	Another very concentrated green.
Goose Liver (100g)	~369	K2	Highest animal source.
Spinach (raw, 1 cup)	~145	K1	Excellent raw source.
Hard Cheese (100g)	~282	K2	Great dietary K2 source.
Kale (raw, 1 cup)	~113	K1	Highly versatile superfood.
Broccoli (boiled, ½ cup)	~110	K1	Common and accessible source.

Maximizing Vitamin K Intake Through Diet

To ensure you're getting a broad spectrum of vitamin K, incorporating both K1 and K2 sources into your diet is beneficial. A diet rich in both is a holistic approach to maintaining strong bones and a healthy heart. For example, you might combine a leafy green salad with an oil-based dressing for K1, and occasionally include fermented foods like natto or high-K2 cheeses for the benefits of K2.

Conclusion: The Ultimate Vitamin K Superstars

While many foods contain this vital nutrient, fermented soybeans (natto) and cooked leafy greens like collard and turnip greens provide the most vitamin K. Including a variety of these powerhouses in your meals ensures you receive both the K1 needed for blood clotting and the K2 crucial for bone and heart health. By diversifying your intake across these rich sources, you can easily meet and exceed daily recommendations for this essential fat-soluble vitamin.

For more detailed nutritional data and recommendations, the Office of Dietary Supplements at the National Institutes of Health is an excellent resource.

Sources

• Office of Dietary Supplements - National Institutes of Health: https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/
• Healthline - Foods High in Vitamin K: https://www.healthline.com/nutrition/foods-high-in-vitamin-k
• Medical News Today - Foods High in Vitamin K: https://www.medicalnewstoday.com/articles/321586

Frequently Asked Questions

What is the single best food source for vitamin K?

The single best food source for vitamin K is natto, a traditional Japanese fermented soybean dish, which contains an exceptionally high amount of vitamin K2.

Is kale or spinach higher in vitamin K?

While both are excellent sources, cooked and boiled kale or spinach typically contain higher concentrations of vitamin K1 per serving than their raw counterparts, due to the reduction of water content.

Does cooking destroy vitamin K?

No, cooking does not destroy vitamin K. In fact, for leafy greens, boiling can actually concentrate the vitamin K content per serving by reducing the water volume.

What are some vegetarian sources of vitamin K2?

For vegetarians, the best sources of vitamin K2 include natto (fermented soybeans) and certain cheeses. The bacteria in the gut also produce some K2.

How can I improve my body's absorption of vitamin K?

Since vitamin K is a fat-soluble vitamin, you can improve its absorption by eating it alongside a source of dietary fat. For example, add some olive oil to your cooked spinach or salad.

Is there a difference between vitamin K1 and K2 in foods?

Yes, vitamin K1 is primarily found in plants and aids in blood clotting, while vitamin K2 is found in fermented and animal products and is more active in bone and heart health.

Who should be cautious about their vitamin K intake?

Individuals taking blood-thinning medications like warfarin must monitor their vitamin K intake carefully, as sudden changes can interfere with the medication's effectiveness.