Vitamin K2 : Health Benefits And Sources

algaecal plus vitamin k2 source

Why is Vitamin K Necessary? | Forms of Vitamin K | Vitamin K Deficiency | Vitamin K2’s Richest Food Sources | Vitamin K2 and Your Health | Adequate Intake of Vitamin K

Why Is Vitamin K Necessary?

Vitamin K2 cleans calcium deposits from your arteries and deposits it in your bones, and you have most likely never heard of it? It’s almost like the old good news/bad news jokes. The good news is Vitamin K2 has been clinically proven to provide extraordinary benefits for bone health and cardiovascular health, plus it is a powerful anti-oxidant and some emerging science indicates it might help your joints and intestinal health. Now for the bad news. It costs $1.5 million per kilogram so most supplement companies find it is not cost effective to include in their formulas. As long as we can buy a house and a Ferrari for the price of a kilo of K2, it may remain a secret that is relegated to research papers! A few companies like AlgaeCal International are dedicated to making vitamin K2 available in significant dosages in spite of the cost, so read on and see why we think it is worth the price.

Forms of Vitamin K

Vitamin K is the name of a group of compounds that are all related to one another. The first one discovered was Phylloquinone or K1. In the last decade most of the research has turned to the more effective Menaquinones, or vitamin K2. The vitamin K2’s are further divided into MK-4, MK-7 and several other forms. Recent studies have shown vitamin MK-7 to be more complete and have additional heart condition benefits.

Vitamin K Deficiency

A healthy intestinal tract can produce Vitamin K but in many cases it is not produced efficiently so it must be supplied by your food. Vitamin K is different from other fat soluble vitamins because it cannot be stored in the body either. It will almost always be necessary to get Vitamin K from your diet.

When you eat vitamin K1 in your food, only 5-10% of ingested K1 is absorbed and reaches your blood, but almost 100% of K2 is absorbed into your blood stream where it can be distributed for beneficial use in tissues including bones and arteries. Vitamin K2 also lasts for several days in your bloodstream compared to K1 which mostly disappears in a few hours.

Foods that include reasonable amounts of vitamin K1 include leafy vegetables, olive oil, cheese, liver, soy beans, brussel sprouts, broccoli, cauliflower, coffee, and green tea. More than 80% of the Vitamin K in western diets consists of vitamin K1. The more beneficial form, K2, is difficult to find in your diet with the exception of the Japanese traditional food, Natto1

Vitamin K2’s Richest Food Sources

The following video by Lara Pizzorno, author of “Your Bones” reveals the best dietary sources of long-chain menaquinone such as the MK7 version of vitamin K2.


While you get a tiny bit of K2, the long-chain menaquinones from certain cheeses such as:

  • English cheese
  • English Blue cheese
  • Swiss Emmental
  • Norwegian Drawsburg cheeses

These cheeses contain somewhere between 0.2 and 0.65, so less than one microgram per gram of cheese. There are 28 grams in an ounce, so this translates to 5.6 to 18.2 micrograms per ounce of cheese.

At least the form of K2 in these cheeses is the most likely to be the longer chain versions of the menaquinones MK7, 8, 9 or 10 and these forms of menaquinones remain in your body for at least three days. A lot longer than the MK4 version of K2, which is cleared out of your system within about six hours.

So how do you know which cheeses are likely to have these long-chain menaquinones in them?

K2 is produced by a lactic acid bacteria that’s used in making these cheeses. In particular, the leuconostoc species and it’s also found in cheeses in which mesophilic lactic acid bacteria species are used as starters, especially lactococcus species. The K2 is not present at all in cheeses that are made through fermentation with thermophilic species such as streptococcus thermophilus, lactobacillus, and bifidobacterium. When these are used as a lactic acid bacteria starter, these thermophilic species do not produce K2.

So what is the practical take away from this arcane information? You are probably rolling your eyes at me now saying, “Good grief. What is she trying to tell us?”

What this means is that only certain cheeses are going to give you K2.

france-605450_640And neither yogurt nor cottage cheese, while they are great sources of calcium and protein are going to give you K2.

What you need to do is ask at you grocery store if they know or if they can find out for you which bacteria were used to produce the cheeses that they are selling. And you want to look for English Blue cheese, Swiss Emmental cheese or Norwegian Drawsburg cheese. The bacteria that are used in the fermentation process to produce these cheeses will give you some vitamin K2.

K2 is also present again, in very small amount and just in the MK4 form which doesn’t stick around long enough to be very helpful for you in liver, chicken, beef, and egg yolks. You need at least 100 micrograms of MK7 every day to activate the vitamin K proteins that put calcium into your bones and keep it out of your arteries. You need 15,000 micrograms of the MK4 version of K2 to produce benefit for your bones and you need 15,000 micrograms of the MK4 version every six to eight hours to have an effect. So what you get in three and a half ounces of pan fried chicken is 12.6 micrograms when you need 15,000 of MK4.

In three and a half ounces of chicken tenders, you are going to get 6.2 micrograms, again, a ridiculously small amount. In three and a half ounces of medium fat boiled ground beef, you are going to get 8.1 micrograms of MK4. And if you go for the low fat beef version, that’s going to give you just 1.7 micrograms. If you like eggs, they will give you a little MK4. Three eggs, if they are hard cooked, contain seven micrograms and if they are fried, you will get a little bit more because there’s a little K1 in the oil. If fried, you will get nine micrograms.

But still, you are going to be getting MK4 and you need 15,000 micrograms every six hours of MK4, so it’s not going to be enough.

In quantities sufficient to really produce a positive effect on your bones, K2 is only found in one unusual and unpalatable in the Western diet food.

And this is a Japanese fermented soybean product called Natto.

Natto, a typical breakfast food, is made from steamed and fermented soy beans. It’s use in Japan dates back hundreds of years to the age of Samurais who believed it increased their strength and quickened their reflexes.

Today about 7.5 billion packages of Natto are sold in Japan each year and Japanese health authorities have invested resources promoting regular use of Natto, including making it an integral part of the Japanese school breakfast programs. In the last ten years several studies have found natto, containing the active component vitamin K2, to increase bone mineral density and reduce bone fractures.2-5

Also, several studies on Vitamin K2 specifically has been found to promote bone metabolism and reduce the incidence of fracture in osteoporosis.6-12 As compared to vitamin K1, vitamin K2 has been found to be more effective in decreasing bone turnover in vitro13-14 and in vivo,15 suggesting that it may offer more bone health benefits than K1.

Natto contains a lot of MK7 form of K2 which is the form that you want. In Japan, natto is sold in 40 grams or 1.4-ounce containers, and each container is considered one serving. But some people eat more than a package of natto at a time and they eat natto very often.

Each package of natto is going to give you 380 micrograms of the MK7. So that is a very healthy serving and it’s enough to support bone health.

So to sum up in the United States, our dietary intake of all forms of vitamin K combined vitamin K1, and all the forms of K2, MK4 and MK7, 8, 9 and 10 is only about 80 micrograms a day, largely because we consume so few leafy green vegetables.

Even in the Netherlands where they eat a lot more vitamin K rich leafy greens and more vitamin K2 rich cheeses that actually contain the long-chain menaquinones than we do, the Rotterdam study found that dietary vitamin K intakes amongst those who are consuming the highest amounts of vitamin K averaged 370 micrograms per day for vitamin K1, and just 45 micrograms a day of menaquinones. But they were the long-chain menaquinones, seven, eight and nine. And these people were eating 100 grams or 3 ounces of green vegetables and 100 grams or 3 ounces of the special cheeses that contain the long-chain menaquinones every day.

So what’s the bottom line for you here? What’s practical?

If natto is not featured in your grocery store, or if you just can’t get passed the slimy texture and the gym sock smell of this fermented soybean product, then to get adequate K2 in the MK7 form which is going to stick around and do something for your bones, you really need to take a supplement. If you are taking AlgaeCal Plus, you are covered. Two capsules of AlgaeCal Plus in the morning and two capsules again at night as is directed, will give you 100 micrograms of MK7. And that is the amount that has been shown to be beneficial to bone in a number of studies now.


Vitamin K2 and Your Health

Vitamin K2 Safety

If you take an anti-coagulant (blood thinner) you should consult your physician before taking vitamin K2 supplements. Vitamin K2 helps normal coagulation of blood. High levels of K2 do not cause abnormal blood clotting. You should not be concerned about taking levels of 45 mg/day or less, as numerous Japanese studies have shown even this high level is safe for adults. Most vitamin K2 supplements offer 45 – 150 micrograms per day.

Vitamin K2 for Pregnant Women

Pregnant women should be especially conscious of their vitamin K intake because the following birth defects have been linked to vitamin K deficiency:

  • Cardiac dysfunction
  • Craniofacial abnormalities
  • Flat nasal bridge
  • Growth disorders
  • Learning disorders
  • Microcephaly
  • Neural tube defects

Vitamin K2 and Your Heart

K2 has been reported to decrease serum cholesterol and cholesterol deposits in the aorta, contributing to the suppression of atherosclerosis.16-17 Vitamin K2 has been linked to a reduction in coronary heart disease. In fact one very large and significant study conducted in the Netherlands in 2004 followed 4800 healthy men and women for ten years. It found vitamin K2 reduced the risk of coronary heart disease mortality by 50%!19 Aortic calcification was also reduced by 30-40% in this famous Rotterdam study.

Adequate Intake Level of Vitamin K

In January 2001, the Food and Nutrition Board of the Institute of Medicine established the adequate intake level for vitamin K in the U.S. as shown below.

Adequate Intake (AI) for Vitamin K
Life Stage Age Males (mcg/day) Females (mcg/day)
Infants 0-6 months 2.0 2.0
Infants 7-12 months 2.5 2.5
Children 1-3 years 30 30
Children 4-8 years 55 55
Children 9-13 years 60 60
Adolescents 14-18 years 75 75
Adults 19 years and older 120 90
Pregnancy 18 years and younger 75
Pregnancy 19 years and older 90
Breastfeeding 18 years and younger 75
Breastfeeding 19 years and older 90

Although the “Adequate Intake” for vitamin K was recently increased, it is not clear if it will be optimal according to more recent science. Some multivitamins can contain small amounts – 10 to 25 mcg of vitamin K. To consume the amount of vitamin K associated with a decreased risk of hip fracture in the Framingham Heart Study (about 250 mcg/day), you need to eat a little more than 1/2 cup of chopped broccoli (the best source of K) or a large salad of mixed greens every day. For optimal bone and heart health most people will need to supplement. AlgaeCal® Plus contains a full 100 mcg/day of vitamin K2 in the MK-7 version.


  1. Kaneki, M et al 2001: Japanese fermented soybean food as the major determinant of large geographic difference in circulating levels of vitamin K2: Possible implications for hip-fracture risk. Nutrition. Vol 17, page 315-321
  2. Katsumaya, H. et al 2002: Usual dietary intake of fermented soybeans (Natto) is associated with bone mineral density in premenopausal women. J Nutr Sci Vitaminol June 48(3) page 207-215
  3. Katsumaya, H. et al 2004: Promotion of bone formation by fermented soybean (Natto) intake in premenopausal women. J Nutri Sci Vitaminol Apr 50(2) page 114-120
  4. Hodges, S.J et al 1991: Depressed levels of circulating menaquinones in patients with Osteoporotic fractures of spine and femoral neck. Bone vol 12, page 387-389
  5. Ikeda, Y. et al 2006: Intake of fermented soybeans, Natto, is associated with reduced bone loss in post menopausal women: Japanese population based osteoporosis study. J Nutri Vol 136, page 1323-1328
  6. Geleijnse, J.M. et al 2004: Dietary intake of menquinone (Vitamin K2) is associated with a reduced risk of coronary heart disease: The Rotterdam Study. Am Soc Nutr Science. May 2004. Nutritional Epidemiology
  7. Manoury E, Jourdon K, Boyaval P, Fourcassié P. Quantitative measurement of vitamin K2 (menaquinones) in various fermented dairy products using a reliable high-performance liquid chromatography method. J Dairy Sci. 2013 Mar;96(3):1335-46. doi: 10.3168/jds.2012-5494. Epub 2013 Jan 17. PMID: 23332840
  8. Hojo K, Watanabe R, Mori T, Taketomo N. Quantitative measurement of tetrahydromenaquinone-9 in cheese fermented by propionibacteria. J Dairy Sci. 2007 Sep;90(9):4078-83. PMID: 17699024
  9. Elder SJ, Haytowitz DB, Howe J, Peterson JW, Booth SL. Vitamin k contents of meat, dairy, and fast food in the u.s. Diet. J Agric Food Chem. 2006 Jan 25;54(2):463-7. PMID: 16417305
  10. Fujita Y, Iki M, Tamaki J, et al. Association between vitamin K intake from fermented soybeans, natto, and bone mineral density in elderly Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) study. Osteoporos Int. 2012 Feb;23(2):705-14. doi: 10.1007/s00198-011-1594-1. Epub 2011 Mar 11. PMID: 21394493
  11. Schurgers LJ, Geleijnse JM, Grobbee DE, et al. “Nutritional intake of vitamins K1 (phylloquinone) and K2 (menaquinone) in the Netherlands.” Journal of nutritional & environmental medicine 9.2 (1999): 115-122.
  12. Photo of cheeses via Pixabay


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