Vitamin K1 & K2

Vitamin K comes in various forms, but the most common forms are derived from plants and bacteria. We get most of our vitamin K from plants, a smaller amount from fermented foods, such as tempeh, and a similarly small amount from bacteria residing in our gut.

In the plant kingdom, vitamin K serves a vital role in photosynthesis. Vitamin K acts as an electron carrier, helping to efficiently capture and store the sun’s energy. In humans, 

vitamin k’s biggest claim to fame is the role it plays in ‘coagulation’ or blood clotting, activating proteins that help blood clot. In fact, the “K” comes from the German word koagulation, which means blood clotting.

Musculoskeletal Health Benefits of Vitamin K

Vitamin K actually describes more than one molecule. In terms of well being there are three important types of vitamin K: vitamin K1, vitamin K2 (M4), and vitamin K2 (M7).

Vitamin K1 is synthesized by plants and is the predominant form in the diet. Vitamin K2 is synthesized by good gut bacteria and found in fermented foods, and in animal products.All variants of vitamin K are structurally similar, but vitamin K1 and vitamin K2 seem to have different effects on various body processes. For instance, vitamin K1 is critical for normal blood clotting, while research suggests vitamin K2 is important for bone and joint health.

The primary distinction between vitamin K2 (M4) and vitamin K2 (M7) is the duration of their activity in the body, with M7 acting longer than M4; giving M7 a more favored status in supplement formulations. The body can convert K1 into K2, but in many people this process is insufficient to achieve optimal K2 levels.

1.  Vitamin K2 Supports Joint Health

Vitamin K2 is required to activate matrix Gla proteins. These proteins are pivotal for optimal cartilage mineralization. Cartilage is mostly soft, which is key  for  cartilage’s shock absorbing properties. Often, bone-like material gets deposited in cartilage; sabotaging its softness and shock absorbing attributes. Matrix Gla proteins help protect cartilage against these unhealthy calcium deposits and promotes joint health.

Additionally, vitamin K is necessary for osteoclacin, a protein produced in bone. Recent research has demonstrated that osteoclacin is important for healthy blood glucose levels and healthy weight. High sugar levels and excess fat are risk factors for unhealthy joints.

 

Boston researchers showed that individuals who have low intake of vitamin K have an increased risk of unhealthy knee joints. (T. Neogi, S. L. Booth, Y. Q. Zhang et al., “Low vitamin K status is associated with osteoarthritis in the hand and knee,” Arthritis and Rheumatism, vol. 54, no. 4, pp. 1255–1261, 2006.)

2.  Vitamin K2 Supports Bone Health

Some research suggests vitamin K2 stimulates bone building cells called osteoblasts. Well-functioning osteoblasts promote normal bone density. Moreover, vitamin K dependent proteins are expressed in certain immune cells. Some investigation implies that these vitamin k dependent proteins help support a healthy response to injury and support healthy inflammation. Chronic, unhealthy inflammation has been shown to increase the cellular activity of osteoclasts, cells that absorb bone. Vitamin k may help re-balance bone cellular activity and support bone health.

 

Dutch investigators demonstrated that supplementing vitamin K2 at 180 microgram/day promoted a healthy bone mineral density in the lumbar spine and femoral neck.(M. H. J. Knapen, N. E. Drummen, E. Smit, C. Vermeer, and E. euwissen, “ Three-year low-dose menaquinone-7 supple- mentation helps decrease bone loss in healthy postmenopausal women,” Osteoporosis International, vol. 24, no. 9, pp. 2499– 2507, 2013)

 

Other Health Benefits of Vitamin K

There are other conditions that folate may assist, although more research is needed and for some conditions results to date have been mixed. Those include:

  • Improves heart health
  • Boosts oral health
  • Supports immune system

Rich Sources of Vitamin K

Green leafy vegetables are major contributors of dietary vitamin K1. Vitamin K2 is frequently found in fermented foods such as natto (fermented soybeans), cheese, and curds.

 

Recommended Dietary Allowance (RDA)

The RDA for vitamins explains how much of each vitamin most people need each day. The quantity of the vitamins depend on gender and age. At the same time, illness, pregnancy and breastfeeding may increase the amount needed.

The recommended adequate intakes (AIs) of vitamin K for individuals, according to the Food and Nutrition Board at the Institute of Medicine:

Infants

0-6 months: 2.0 micrograms (mcg) per day

7 to 12 months: 2.5 mcg per day

Children

1 to 3 years: 30 mcg per day

4 to 8 years: 55 mcg per day

9 to 13 years: 60 mcg per day

Adolescents and adults

Males and females aged 14-18 years: 75 mcg per day

Males and females aged 19 and older:

90 mcg per day for females (including pregnant and breastfeeding mothers)

120 mcg/day for males

 

Precautions

Vitamin K from natural foods is generally well tolerated. RDA amounts can usually be obtained from a balanced, healthful diet.

Upper limits for vitamin K consumption have not been established given vitamin K's low potential for toxicity.

However, vitamin K interacts with certain prescription blood thinners and any consideration of supplementation should be discussed with a qualified health professional familiar with your unique medical history. 

 

References

(2016). Vitamin K fact sheet for health professionals. National Institutes of Health. Retrieved from https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/

(2017). Vitamin K. Micronutrient Information Center. Retrieved from http://lpi.oregonstate.edu/mic/vitamins/vitamin-K

(2017). Vitamin K. The World’s Healthiest Foods. Retrieved from http://www.whfoods.com/genpage.php?tname=nutrient&dbid=112

Azuma, K., Ouchi, Y., & Inoue, S. (2014). Vitamin K: Novel molecular mechanisms of action and its roles in osteoporosis. Geriatr Gerontol Int, 14, 1–7. doi: 10.1111/ggi.12060

Azuma, K., Casey, S. C., Ito, M., Urano, T., Horie, K., Ouchi, Y., & … Inoue, S. (2010). Pregnane X receptor knockout mice display osteopenia with reduced bone formation and enhanced bone resorption. J Endocrinol, 207(3), 257–263. doi:10.1677/JOE-10-0208.

Misra, D., Booth, S. L., Tolstykh, I., Felson, D. T., Nevitt, M. C., Lewis, C. E. & … Neogi, T. (2013). Vitamin K deficiency is associated with incident knee osteoarthritis. The American Journal of Medicine, 126(3), 243-248. doi:10.1016/j.amjmed.2012.10.011

Neogi, T., Booth, S. L., Zhang, Y. Q., Jacques, P. F., Terkeltaub, F., Aliabadi, P., & Felson, D. T. (2006). Low Vitamin K status is associated with osteoarthritis in the hand and knee. Arthritis & Rheumatism, 54(4), 1255–1261. doi:10.1002/art.21735

Neogi, T., Felson, D. T., Sarno, R., & Booth, S. L. (2008). Vitamin K in hand osteoarthritis: Results from a randomised clinical trial. Ann Rheum Dis, 67(11): 1570–1573. doi:10.1136/ard.2008.094771

Otten, J. J., Hellwig, J. P., & Meyers, L. D. (Eds.). (2006). Dietary reference intakes: The essential guide to nutrient requirements. Washington D.C.: National Academy of Sciences.

Shea, M., K., Kritchevsky, S. B., Hsu, F. C., Nevitt, M., Booth, S. L., Kwoh, C. K., & … Loeser, R. F. (2015). The association between vitamin K status and knee osteoarthritis features in older adults: The Health, Aging and Body Composition Study. Osteoarthritis Cartilage, 23(3): 370-378. doi:10.1016/j.joca.2014.12.008.

Stern, J. T. (1999). The cost of bent­knee, bent­hip bipedal gait. A reply to Cromptonet al. Journal of Human Evolution, 36(5), 567­570. http://dx.doi.org/10.1006/jhev.1999.0290

M. Yamaguchi, “Regulatory mechanism of food factors in bone metabolism and prevention of osteoporosis,” Yakugaku Zasshi, vol. 126, no. 11, pp. 1117–1137, 2006.

S.Cockayne,J.Adamson,andS.Lanham-New,“VitaminKand the prevention of fractures: systematic review and meta-analysis of randomized controlled trials,” Archives of Internal Medicine, vol. 166, no. 12, pp. 1256–1261, 2006.

M. Shiraki, Y. Shiraki, C. Aoki, and M. Miura, “Vitamin K2 (menatetrenone) e ectively prevents fractures and sustains lumbar bone mineral density in osteoporosis,” Journal of Bone and Mineral Research, vol. 15, no. 3, pp. 515–521, 2000.

J. Iwamoto, T. Takeda, and Y. Sato, “E ects of vitamin K2 on osteoporosis,” Current Pharmaceutical Design, vol. 10, no. 21, pp. 2557–2576, 2004.

M. H. J. Knapen, N. E. Drummen, E. Smit, C. Vermeer, and E. euwissen, “ ree-year low-dose menaquinone-7 supple- mentation helps decrease bone loss in healthy postmenopausal women,” Osteoporosis International, vol. 24, no. 9, pp. 2499– 2507, 2013.

T. Neogi, S. L. Booth, Y. Q. Zhang et al., “Low vitamin K status is associated with osteoarthritis in the hand and knee,” Arthritis and Rheumatism, vol. 54, no. 4, pp. 1255–1261, 2006.

D. Misra, S. L. Booth, I. Tolstykh et al., “Vitamin K de ciency is associated with incident knee osteoarthritis,” American Journal of Medicine, vol. 126, no. 3, pp. 243–248, 2013.

M. S. Abdel-Rahman, E. A. M. Alkady, and S. Ahmed, “Menaquinone-7 as a novel pharmacological therapy in the treatment of rheumatoid arthritis: A clinical study,” European Journal of Pharmacology, vol. 761, pp. 273–278, 2015.

M. H. J. Knapen, N. E. Drummen, E. Smit, C. Vermeer, and E. euwissen, “ Three-year low-dose menaquinone-7 supple- mentation helps decrease bone loss in healthy postmenopausal women,” Osteoporosis International, vol. 24, no. 9, pp. 2499– 2507, 2013

 

 

 Lucas J. Bader MD

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