What Foods Contain Vitamin K2?
Published: August 28th, 2024
Vitamin K is essential for your health. To ensure you get enough of this important nutrient, it’s crucial to understand what foods contain vitamin K2—one of the vitamin’s unique forms. While vitamin K is widely recognized for aiding with blood clotting, it has other lesser-known benefits too. Its K2 form, specifically, has been linked to heart and bone health.
Keep reading to learn what foods contain vitamin K2, and why it’s so important for your health.
What is Vitamin K2?
Vitamin K2, also called menaquinone, is a fat-soluble vitamin that’s found in animal products and fermented foods. It’s mostly created by bacteria: the same bacteria used to ferment foods, like cheeses and soybeans. It’s no wonder we see those products topping the list of foods rich in vitamin K2!
The other type of vitamin K—called phylloquinone or K1—is mostly found in leafy green vegetables.
DIGGING DEEPER
Fermentation and Vitamin K2: It’s About the Process, Not the Product
To truly understand the relationship between fermentation and vitamin K2, it’s important to recognize that it’s not just the type of food that matters—it’s the way the food is processed.
Fermentation is a powerful process that significantly enhances the vitamin K2 content of certain foods. This is because Vitamin K2 is produced by specific strains of bacteria during fermentation.
Let’s consider cabbage and sauerkraut. Cabbage on its own is a nutritious vegetable and an excellent source of vitamin K1—also known as phylloquinone, found in leafy green vegetables—but it contains little to no vitamin K2. However, when cabbage is fermented to produce sauerkraut, the bacterial fermentation process generates vitamin K2. The bacteria used in fermentation synthesize menaquinones (vitamin K2), transforming cabbage into sauerkraut and a potent source of this essential vitamin.
This phenomenon isn’t limited to fermented vegetables or dairy. The fermentation process used by Green Pasture Products in its fermented cod liver oil not only preserves the nutrients found in cod liver oil but also boosts the levels of vitamin K2, making it a concentrated supplemental source of this vital nutrient.
Best Food Sources of Vitamin K2
Unfortunately, there is relatively little information about foods rich in vitamin K2; many national food databases—the top source for nutritional information like this—simply list total vitamin K or its K1 form.
Thankfully, the databases of the United States, the Netherlands, and Turkey contain vitamin K2 data, broken down into smaller subcategories of menaquinones, MK4–MK10. These findings were presented in a 2017 analysis titled ‘Menaquinones, Bacteria, and Foods: Vitamin K2 in the Diet’ by Barbara Walther and Magali Chollet.
Here are the best food sources of vitamin K2, based on their analysis and a vitamin k food chart:
- Fermented Vegetables: A traditional Japanese food made from fermented soybeans, natto, is the richest natural source of vitamin K2, specifically MK-7. Lower on the list, but perhaps more familiar to people from other parts of the world, is sauerkraut.
- Dairy Products: Hard cheeses and fermented dairy products created with a specific type of “mesophilic” bacteria are rich in vitamin K2, particularly in the MK-8 and MK-9 forms. Fresh butter, while not concentrated as other foods, has a decent amount of the MK-4 form.
- Animal Products: An example of a non-fermented food that is rich in vitamin K2 is liver, especially from beef and pork. Eggs and meats also contain smaller amounts. The MK-4 form makes up the majority of these foods’ vitamin K2 concentration.
- Supplements: In 2023, the Weston A. Price Foundation published tests of vitamin K2 in 30 animal products and four brands of cod liver oil. Green Pasture Products’ fermented cod liver oil stood out as an excellent source of vitamin K2, offering the highest concentration per serving among the tested brands. It makes sense that Green Pasture Products’ oils are an excellent source of this essential nutrient as vitamin K2 is often found concentrated in the fat of certain foods.
Natural Vitamin K2 vs. Synthetic Sources
We at Green Pasture believe that choosing natural sources of vitamins, particularly vitamin K2, is crucial. Synthetic vitamins, while seemingly convenient, often lack the co-factors and complex compounds that make natural vitamins more effective and easier for your body to absorb. As discussed in Green Pasture’s blog on synthetic versus natural vitamins, natural vitamins come as a complete package, offering better absorption and efficacy compared to their synthetic counterparts.
Health Benefits of Vitamin K2
Research about the health benefits of vitamin K2 is about as scarce as that of the foods that contain it. More study is needed.
That being said, several observational studies and analyses have shed light on some wellness benefits of vitamin K2, including:
- Bone health: A 2022 meta-analysis of postmenopausal women found that vitamin K2 has a positive impact on building and maintaining strong bones and teeth.
- Heart health: A 2023 review of clinical studies observed a link between vitamin K2 and reduced calcium buildup in arteries, potentially helping prevent heart disease.
Although the analyses were observational, meaning they can’t prove cause and effect, there is strong evidence suggesting vitamin K2’s positive impact on both heart and bone health.
Vitamin K2 in Your Diet
To get adequate amounts of vitamin K2 in your diet, be mindful of the many different foods that contain vitamin K2. Consider trying one of Green Pasture’s fermented cod liver oil, concentrated butter oil, or blended oil. These products are made from fermented foods and dairy products known to contain vitamin K2.
If you’re unsure about how to incorporate these foods into your diet or want personalized advice, consult a nutritionist or primary care doctor.
Taking these steps will help you enjoy the full range of benefits that vitamin K2 has to offer, supporting your long-term wellness and vitality.
References
Walther, Barbara, and Magali Chollet. “Menaquinones,
Bacteria, and Foods: Vitamin K2 in the Diet.” IntechOpen, March 22, 2017.
https://www.intechopen.com/chapters/50921.
Fallon Morell, Sally. “Values for the Fat-Soluble Activators.” The Weston A. Price Foundation, December 7, 2023. https://www.westonaprice.org/health-topics/values-for-the-fat-soluble-activators.
Ma, Ming-Ling et al. “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 vol. 10 979649. 11 Aug. 2022, doi:10.3389/fpubh.2022.979649
Aaseth, Jan O et al. “Vitamin K and Calcium Chelation in
Vascular Health.” Biomedicines vol. 11,12 3154. 27 Nov. 2023,
doi:10.3390/biomedicines11123154
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