Vitamin K2 in Bone and Heart Health

Gosh I love cheese! There are so many varieties, including different flavors, textures, and smells. Sometimes I will indulge in a cheese plate with an aged goat, a creamy blue, and an assortment of fruits and olives. It’s so easy and so delicious! However, not only does cheese taste good but it also contains some very important vitamins and minerals, especially vitamin K (we will focus on K2) and calcium. These two important nutrients are unique in the fact that they work together to maintain bone and heart health. Along with fat-soluble vitamins A and D, a concert of actions comes together to offer protective health benefits. 

So firstly lets talk about calcium, since everyone is somewhat familiar with this mineral. Calcium is an essential mineral that plays prominent roles in both bone health and cell-signaling. In order to have adequate amounts of calcium we must make sure to get it through our diet via calcium rich foods. As with everything, a fine balance between too much and too little is essential in regards to optimal health. Luckily a healthy body will be able to regulate the amounts accordingly, drawing calcium from the bones if there is too little in the blood, or reducing absorption when dietary intake is adequate (1). However, in order for calcium to be properly absorbed, distributed, and utilized, additional vitamins are key!

Read more about calcium is in this wonderful blog post!

Lets start with vitamin K. There are two natural forms of vitamin K, including vitamin K1 (phylloquinone), which is found in darky leafy greens and is known for its ability to clot blood, and the lesser-known vitamin K2 (menaquinone). When an animal grazes on vitamin K1 rich foods such as quickly growing spring grass, vitamin K1 is converted to vitamin K2 through enzymatic action and stored in the tissues. This conversion rate varies widely between different animal species and happens to be most present in mammary glands. Vitamin K2 can also be produced through certain lactic acid bacterial fermentation (2).

It is very important to note that these two vitamins do not have similar roles and are actually quite different in their biochemical functions. In the past researchers had a tendency to disregard vitamin K2, however new research is demonstrating that these two forms of vitamin K should be seen as two different vitamins all together with complete unique functions within the body. While K1 is preferentially used to activate blood-clotting proteins, vitamin K2 is used to help distribute dietary calcium into places where it belongs, such as bones and teeth, and keep it away from soft tissues such as arteries (2).

Furthermore, vitamin K2 works in synergy with vitamins A and D. Both vitamins A and D act as messengers, telling cells to make certain proteins, while vitamin K2 activates these proteins to complete their functions. The function of these proteins is to bind calcium and to move/organize the calcium throughout the body. One of these proteins is called osteocalcin, which directs calcium and phosphorous salt deposits into bones and teeth. Furthermore, vitamins A and D control the amounts of Gla protein made available which also plays an essential role in moving calcium into bone tissue and protecting soft tissues, such as arteries from becoming calcified. Both the Gla and osteocalcin proteins absolutely require the presence of vitamin K2 to become activated. Finally, vitamin D plays an additional very important role, helping to increase calcium absorption in the gut. So as you can see….it is a very complex synergistic activity of all combined to promote optimal bone density and protect soft tissues from calcification (2).

So where am I going with this? Bone health and heart health! If there is too little K2, then consequently these important proteins osteocalcin and Gla, remain deactivated, and therefore calcium is not distributed where it should be. Consequentially, bone density may decrease and the risk of depositing calcium in soft tissues such as arteries increases. Multiple studies have found an association between vitamin K2 supplementation and a reduced risk of coronary heart disease, while vitamin K1 was not correlated to any positive outcomes (3,4). Furthermore, a large clinical study found that K2 supplementation significantly increased bone mineral density in Chinese postmenopausal osteoporotic women, with effects comparable to that of a current drug used in the treatment of osteoporosis called alfacalcidol (5). Similar results were found in a study of postmenopausal Japanese women treated with a low dose of 1.5mg/day of menaquinone-4 (vitamin K2, MK-2). Researchers found that participants who were not given K2 supplementation had a lower bone mineral density after 12 months than those who had low dose supplementation (6).

So what foods contain vitamin K2?? Unlike vitamin K1 which is found most abundantly in new sprouts and leafy greens, vitamin K2 is found most readily in dairy, eggs, and meats, as well as some fermented foods like natto and sauerkraut. Remember what I said earlier? Animals eat the vitamin K1 rich grass, convert it to vitamin K2, and store it in their tissues, especially mammary glands. Since vitamin K2 is a fat-soluble vitamin, just like vitamins A and D, you will find it most concentrated in fat containing animal products. However, the most important part is to buy pasture-raised animal products. Since pasture-raised animals are allowed to graze on grass they not only will have higher vitamin K2 levels but they will be more nutrient dense overall compared to conventional grown. Furthermore because fermentation via lactic acid bacteria also produces vitamin K2 you can find it in fermented veggies and soybeans. Natto, a traditional Japanese breakfast staple made from soybeans, has the highest amount of concentrated K2. It requires an acquired taste as it smells and tastes very strong. Read below for a more detailed list on vitamin K2 rich foods (2,7).

Vitamin K2 (µg per 100g)
Natto (fermented soybeans)
Goose Liver
Hard Cheese
Soft Cheese
Egg Yolk (pasture-raised)
Egg Yolk (conventional)
Chicken Liver
Chicken Breast
Ground Beef  (medium-fat)
Whole Milk

So you might be asking, how much K2 do I need to eat? Interestingly humans do not possess the ability to absorb much more than 200µg of vitamin K1 per day from vegetables. Absorption is better if leafy greens are consumed throughout the day instead of eaten at one sitting. The efficiency of the conversion rate of vitamin K1 to vitamin K2 in human tissue is unknown, however studies have shown that vitamin K2 is inversely associated with heart disease and mortality while K1 did not have this effect. Therefore, new research studies are suggesting that vitamin K2 conversion from vitamin K1 is not sufficient in humans, highlighting the need to eat vitamin K2 rich food sources to meet our daily needs (2).  So the answer is…eat a little quality (grass-fed/organic) vitamin K2 rich food every day to your liking! Now you have a good reason to eat a little cheese with your glass of wine J

With that I will leave you with a delicious savory ricotta recipe, perfect for dipping or spreading. Also, if you don't want to get all fancy, eating just plain ricotta is delicious too!

Herbed Ricotta
Makes about 2 cups

1 15oz container organic pasture-raised ricotta (I use Organic Valley)
1/3 cup feta in brine, strained and crumbled
Zest of 1 lemon
2 tablespoons lemon juice
1 clove garlic, minced
1 tablespoon finely minced fresh herbs (rosemary, chives, thyme, etc)
¼ cup flat leaf parsley, finely chopped
2 tablespoons extra virgin olive oil
¼ tsp sea salt
Fresh ground pepper to taste


Mix all together and refrigerate at least 4 hours or overnight to allow the flavors to blend.

Serving Suggestion: Spread on crusty bread and top with sliced tomatoes or spread on sliced cucumber slices and top with broccoli/alfalfa sprouts as garnish.
1. Linus Pauling Institute. Calcium Accessed March 16, 2015.
2 Masterjohn C. On the Trail of the Elusive X-Factor: A Sixty-Two-Year-Old Mystery Finally Solved. Accessed March 16, 2015.
3. Geleijnse JM, Vermeer C, Grobbee DE, Schurger LJ. Dietary Intake of Menaquinone is Associated with a Reduced Risk of Cornary Heart Disease: The Rotterdam Study. Journal of  Nutrition. 2004:3100-3105
4. Juanola-Falgarona M, Salas-Salvado J, Martinez MA, et al. Dietary Intake of Vitamin K is Inversely Related with Mortality Risk. Journal of Nutrition. 2014;743-749.
5. Jiang Y, Zhang ZL, Zhang ZL, Zhu, HM, et al. Menatetrenon versus alfacalcidol in the treatment of Chinese postmenopausal women with osteoporosis: a multicenter, randomized, double-blinded, double-dummy, positive drug controlled clinical trial. Clin Interv Aging. 2014;9:121-127.
6. Koitaya N, Sekiguchi M, Tousen Y, et al. Low-dose vitamin K2 (MK-4) supplementation for 12 months improves bone metabolism and prevent forearm bone loss in postmenopausal women. J Bone Miner Metab. 2014;32(2):142-150.
7. Walther B, Karl JP, Booth SL, et al. Menaquinones, Bacteria, and the Food Supply-The Relevance of Dairy and Fermented Food Products to vitamin K Requirements. Adv Nutr. 2013;4:4630473.

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