Nutrient Spotlight: Vitamin K2
Vitamin K is one of the fat soluble vitamins, along with Vitamins A, D, and E. This means it’s absorbed with dietary fat. In short, it’s important for blood clotting, bone health and impacts hormone regulation.
What many people don’t know is there are actually 2 natural forms of vitamin K:
- Vitamin K1 (phylloquinone) is found in plant sources. It’s most useful for blood clotting.
- Vitamin K2 (menaquinone) is synthesized in the intestines or gut with the help of bacteria. For this reason, it’s found in animal foods and fermented plant foods. Vitamin K2 is most useful in bone health (including teeth), cardiac health, improving the way the body uses blood sugar, and hormone production (1-7). A new study has shown a 12% (very significant) increase in cardiac output from Vitamin K2 (1) supplementation. This may be because Vitamin K2 is part of the electron transport chain for mitochondria function, which may boost energy.
Vitamin K2 has several sub types, the most well known being MK7. However, all the subtypes–MK4, MK7, MK10, etc–are referred to as MKs, which is short for menaquinone.
Some providers and researchers reference Vitamin K2 as an “activator” nutrient, meaning it helps other nutrients do their jobs more efficiently, or “work,” the way they should. Vitamin K2 supports cardiac function, specifically improving arterial calcification, or how the body deposits calcium for reduction of heart disease (4).
An example of this “activator” nutrient includes calcium and Vitamin D. Calcium, Vitamin D and K2 work synergistically for cardiac and bone health (7). Think of vitamin K2 as a carrier nutrient to help take calcium to the bone, versus arteries, kidneys and other tissues. It’s kind of like the hose that takes gas from the pump to your car. We need K2 to ensure calcium goes to the right place. For this reason, you may see more and more supplements coming to stores combining Vitamin D3 and K2; opt for those when possible. Some recommended brands include: Microbiome Labs, Thorne, Seeking Health, OrthoMolecular, Designs for Health
Persons with extended periods of antibiotic usage, compromised gut flora, liver function or dysbiosis, may test low in K2. So, consider intake with food and/or try supplementation. In fact, studies have shown broad spectrum antibiotic use substantially decreases Vitamin K2 as much as 70 to 80% (5).
How much do we need?
The general recommendation = 90 ug/day (though no official Recommended Dietary Allowance exists).
Food sources include:
Unfortunately, the foods highest in K2 are not very favorable to most people’s taste buds. The best foods include natto (a fermented soybean popular in Japan) and liver.
- Fermented foods (natto, fermented soy)
- Liver and organ meat
- Egg yolks
- Dark meat from chicken
- Ground beef
In general, this is a nutrient most of us could use more of. Ideally, we’d all be consuming more of the food sources above, but palate and food tolerances come into play. Supplements can be helpful when combined with a foundation of real food.