Vitamin K1 & K2: Stimulates Joint Health
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 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 promote joint health.
Additionally, vitamin K is necessary for osteocalcin, a protein produced in bone. Recent research has demonstrated that osteocalcin 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 micrograms/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. Geuwissen, “Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women,” Osteoporosis International, vol. 24, no. 9, pp. 2499–2507, 2013.)
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
- National Institutes of Health. (2016). Vitamin K fact sheet for health professionals. Retrieved from https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/
- Micronutrient Information Center. (2017). Vitamin K. Retrieved from http://lpi.oregonstate.edu/mic/vitamins/vitamin-K
- The World’s Healthiest Foods. (2017). Vitamin K. 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. Geriatrics & Gerontology International, 14(1), 1-7. https://doi.org/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. Journal of Endocrinology, 207(3), 257-263. https://doi.org/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. https://doi.org/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. https://doi.org/10.1002/art.21735
- Neogi, T., Felson, D. T., Sarno, R., & Booth, S. L. (2008). Vitamin K in hand osteoarthritis: Results from a randomized clinical trial. Annals of the Rheumatic Diseases, 67(11), 1570-1573. https://doi.org/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 and Cartilage, 23(3), 370-378. https://doi.org/10.1016/j.joca.2014.12.008
- Stern, J. T. (1999). The cost of bent knee, bent hip bipedal gait. A reply to Crompton et al. Journal of Human Evolution, 36(5), 567-570. https://doi.org/10.1006/jhev.1999.0290
- Yamaguchi, M. (2006). Regulatory mechanism of food factors in bone metabolism and prevention of osteoporosis. Yakugaku Zasshi, 126(11), 1117-1137.
- Cockayne, S., Adamson, J., & Lanham-New, S. (2006). Vitamin K and the prevention of fractures: Systematic review and meta-analysis of randomized controlled trials. Archives of Internal Medicine, 166(12), 1256-1261.
- Shiraki, M., Shiraki, Y., Aoki, C., & Miura, M. (2000). Vitamin K2 (menatetrenone) effectively prevents fractures and sustains lumbar bone mineral density in osteoporosis. Journal of Bone and Mineral Research, 15(3), 515-521.
- Iwamoto, J., Takeda, T., & Sato, Y. (2004). Effects of vitamin K2 on osteoporosis. Current Pharmaceutical Design, 10(21), 2557-2576.
- Knapen, M. H. J., Drummen, N. E., Smit, E., Vermeer, C., & Geuwissen, E. (2013). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International, 24(9), 2499-2507.
- Neogi, T., Booth, S. L., Zhang, Y. Q., et al. (2006). Low vitamin K status is associated with osteoarthritis in the hand and knee. Arthritis and Rheumatism, 54(4), 1255-1261.
- Misra, D., Booth, S. L., Tolstykh, I., et al. (2013). Vitamin K deficiency is associated with incident knee osteoarthritis. American Journal of Medicine, 126(3), 243-248.
- Abdel-Rahman, M. S., Alkady, E. A. M., & Ahmed, S. (2015). Menaquinone-7 as a novel pharmacological therapy in the treatment of rheumatoid arthritis: A clinical study. European Journal of Pharmacology, 761, 273-278.
- Knapen, M. H. J., Drummen, N. E., Smit, E., Vermeer, C., & Geuwissen, E. (2013). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International, 24(9), 2499-2507.
