The Importance of Vitamin K2
While vitamin K1 is widely known for its role in blood clotting, vitamin K2 (menaquinone) plays a crucial part in regulating calcium in the body. Its primary function is to activate proteins that direct calcium to where it is needed, such as bones and teeth, and away from soft tissues like arteries and kidneys. A sufficient intake of K2 is essential for promoting bone density and supporting cardiovascular health by preventing arterial calcification. However, unlike K1, K2 is not abundant in the standard Western diet, making it necessary to focus on specific food groups to obtain it naturally.
The Two Main Forms of Vitamin K2: MK-4 vs. MK-7
Vitamin K2 exists in several subtypes, with MK-4 and MK-7 being the most recognized. Their primary difference lies in their origin and half-life within the body.
MK-4 (Menaquinone-4)
- Source: Found exclusively in animal products.
- Foods: Examples include egg yolks, liver, and grass-fed butter.
- Function: Plays a vital role in the health of various organs and tissues, including the brain and salivary glands.
- Half-Life: Has a shorter half-life in the body than MK-7.
MK-7 (Menaquinone-7)
- Source: Primarily synthesized by bacteria during fermentation.
- Foods: Exceptionally high in natto, with moderate amounts found in certain cheeses and sauerkraut.
- Function: Has a stronger effect on bone health and arterial stiffness.
- Half-Life: Possesses a longer half-life, meaning it remains active in the body for an extended period.
Where Can I Find Vitamin K2? The Richest Food Sources
To boost your intake of this vital nutrient, you need to look beyond leafy greens and include a mix of fermented and high-fat animal products in your diet. Absorption is significantly enhanced when K2 is consumed with dietary fats.
Fermented Foods
- Natto: The undisputed king of vitamin K2. This traditional Japanese dish of fermented soybeans is the most concentrated natural source, particularly rich in the long-chain MK-7 subtype. It is an acquired taste, but a small serving provides a massive dose of K2.
- Sauerkraut: Fermented cabbage contains a moderate amount of K2, along with beneficial probiotics that support gut health, which in turn helps your body produce its own K2.
- Kefir and Fermented Milk: These fermented dairy drinks also contain good levels of K2, especially in the full-fat versions.
High-Fat Animal Products
- Organ Meats: Liver, especially from grass-fed animals, is an excellent source of the MK-4 form of K2. Goose liver pâté is particularly high.
- Egg Yolks: Eggs from pasture-raised, grass-fed chickens contain more K2 than those from conventionally raised hens. The yolk is where the K2 is concentrated.
- Certain Cheeses: Hard and soft cheeses, especially Gouda, Brie, and blue cheese, contain notable amounts of K2. The menaquinone content is higher in full-fat varieties.
- Grass-Fed Butter: Butter from grass-fed cows is a source of MK-4. Since K2 is fat-soluble, the higher fat content contributes to a higher concentration.
- Fatty Fish: While not as potent as natto, fatty fish like salmon and sardines contain some vitamin K2.
Comparison of Key Vitamin K2 Sources
| Food Source | Type of K2 (Menaquinone) | Approximate K2 per 100g | Notes |
|---|---|---|---|
| Natto | Primarily MK-7 | 1103.4 mcg | Richest known source; strongest effect on bones and arteries. |
| Goose Liver Pâté | Primarily MK-4 | 369.0 mcg | Excellent, but often not a staple food source. |
| Hard Cheeses (e.g., Gouda) | Primarily MK-8, MK-9 | 76.3 mcg | Good source, higher in full-fat varieties. |
| Soft Cheeses (e.g., Brie) | Primarily MK-8, MK-9 | 56.5 mcg | Moderate source, good for boosting intake. |
| Egg Yolk (pasture-raised) | Primarily MK-4 | 15.5 mcg | K2 is concentrated in the yolk, not the white. |
| Chicken Liver | Primarily MK-4 | 12.6 mcg | Organ meats are a concentrated source. |
Enhancing Your K2 Intake
- Pair with Fat: As a fat-soluble vitamin, K2 is best absorbed when consumed with a source of healthy fat, such as the fat naturally present in dairy, eggs, or meats, or by adding healthy oils to fermented foods.
- Support Gut Health: A healthy gut microbiome can produce some K2. Eating fermented foods like sauerkraut not only provides K2 directly but also supports the beneficial bacteria in your gut.
- Consume with Vitamin D: K2 and Vitamin D work synergistically to support bone and heart health. They help ensure calcium is utilized correctly by the body.
- Consider Supplements: For those who cannot consume these specific foods regularly, supplements containing MK-4 and MK-7 are a practical alternative. Always consult a healthcare professional before starting supplementation.
Conclusion
While finding vitamin K2 requires moving beyond standard fruits and vegetables, its crucial role in bone and cardiovascular health makes the effort worthwhile. By incorporating fermented foods like natto, alongside pasture-raised animal products such as eggs, liver, and high-fat cheeses, you can ensure a consistent and effective dietary intake. For a convenient way to boost your levels, especially if these foods are not part of your regular diet, consider discussing supplementation with a healthcare provider. Understanding where to find vitamin K2 and how to best absorb it is a key step toward a balanced and nutritious diet.
Learn more about vitamin K2 and bone health in this authoritative study(https://www.lesaffre.com/trends-mag/vitamin-k2-a-super-vitamin-with-lifelong-benefits/).
