Health knowledge made personal
|
The Amazing Vitamin K Story by JP Saleeby, MD Vitamin K is a lipophilic vitamin (meaning it is fat soluble) and is required chiefly for blood coagulation and metabolism of bone and other tissues. There are two natural forms of this vitamin and several synthetic versions. Vitamin K1, also known as phytomenadione, and Vitamin K2, menaquinone, are the two natural forms. Vitamin K2 is produced chiefly by bacteria in our large intestines. Vitamin K1 is found in green leafy vegetables such as spinach, turnip greens, Swiss chard, and the brassica vegetables like cabbage, broccoli, Brussels sprouts, and kale. Fruits like kiwifruit and avocado, as well as soybean oil are other food sources of Vitamin K. The chief utilization of Vitamin K in medicine as a "therapeutic" is in its role with the coagulation of blood. It plays a key role in factors II, VII, IX and X as well as in protein-C and protein-S. All of these blood factors and proteins are linked to the clotting cascade that prevents us from hemorrhaging in the event of a severe traumatic injury. Additionally, Vitamin K has a significant role in bone metabolism with a relation to osteocalcin. It acts as a bone building hormone in a way, much like Vitamin D. Osteocalcin is synthesized by Vitamin K and is the "matrix" in bone that holds the calcium molecules together. Without Vitamin K, hip bone fracture rates increase despite adequate Vitamin D and calcium intake. In the 1998 Nurse’s Health Study, oral administrations of 110 micrograms per day of Vitamin K proved to decrease hip fractures when compared to control subjects. Vitamin K is important in vascular biology as well, especially in the realm of artery plaque formation (calcification). There are Vitamin K dependent proteins involved in atherosclerosis or hardening of the arteries. The process of calcium plaque formation is hindered with adequate Vitamin K levels in circulation. Warfarin (Coumadin ®) is a drug often used to treat folks with coronary artery disease (CAD) and to prevent blood from clotting in heart chambers and deep veins where severe compilations may arise. However, while treating certain medical conditions with these blood thinners, which inactivate Vitamin K, we create other problems. Chief among these problems are an increase in our risk for developing arterial plaques, the possibility of affecting our immune system, and the likely impediment of bone mineralization. Vitamin K's effect on coronary arteries goes like this. With low levels of circulating Vitamin K in the serum, there is an impact on the function of a protein within the endothelial lining of the arteries called the Matrix Gla protein (MGP). The effect of low Vitamin K on this protein is that it allows for an increase deposition of calcium in arteries. Drugs that lower Vitamin K's effect in a sense raise the risk for coronary artery disease. Vitamin K facilitates our immune system with positive links to phagocytosis and chemotaxis (the process by which “microorganism attacking cells" in our body find and eliminate infectious organisms). Furthermore, Vitamin K appears to have a role in apoptosis, the process of natural and desirable cell death. Apoptosis is the process by which our bodies can eliminate damaged, old or mutated cells thus reducing many forms of cancers. cephalosporins (an antibiotic class) can lead to K1 deficiencies by interference with enzyme function. Furthermore, the drugs cholestyramine, cholestipol, orlistat, and the fat substitute, olestra, have been noted to decrease Vitamin K absorption, in all probability leading to a drop in serum Vitamin K levels that can affect health. Because newborns are susceptible to clotting abnormalities, due to immature livers and sterile guts (inability to have E. coli produce Vitamin K2), they are usually born deficient in varying degrees. There is a 1.5% incidence of unexpected bleeding in newborns due to low levels of Vitamin K. Mothers on anticonvulsants, rifampin and isoniazid (both antibiotics) while pregnant tend to have offspring with sterile guts and an even higher incidence of Vitamin K deficiency. Therefore, the American Academy of Pediatrics recommends about 1.0 milligram of Vitamin K1 be administered to each newborn. There is a connection in theory with Alzheimer’s disease. The APOE4 gene that has been implicated in Alzheimer's disease seems to be responsible for low Vitamin K levels in this subset of patients. It is surmised that supplementation with Vitamin K may reduce the occurrence of Alzheimer's disease, but more research is needed. There also appears to be a connection with some types of cancers. Interestingly, there are two Japanese studies showing females with liver disease with a high risk for liver cancer, having a 90% reduction in development of liver malignancy if they were supplemented with Vitamin K. In a 2008 published German study of male subjects, there was a drop in prostate cancer risk with Vitamin K supplementation. Vitamin K must be rather important to our body as there are at least three ways in which it is maintained; by diet (eating greens), by production in our gut (bacterial), and by enzymatic recycling. Sometimes the importance of a particular substance can be found in the redundancies our body creates to conserve it, such is the case with Vitamin K. Pearls from Dr. Saleeby:
JP Saleeby, MD is an integrative and nutritional medicine practitioner. He has been the chief formulator for a number of independent nutraceutical companies. He is a medical writer / blogger and offers telemedicine consultations to his patients. (c) 2011 References: Berkner, K. L. and Runge, K. W. (2004), “The physiology of vitamin K nutriture and vitamin K-dependent protein function in atherosclerosis”. Journal of Thrombosis and Haemostasis, 2: 2118–2132. Neil C Binkley, Diane C Krueger, Tisha N Kawahara, Jean A Engelke, Richard J Chappell and John W Suttie. (2002) "A high phylloquinone intake is required to achieve maximal osteocalcin {gamma}-carboxylation". American Journal of Clinical Nutrition 76 (5). Higdon (2008). "Vitamin K" . Linus Pauling Institute, Oregon State University. http://lpi.oregonstate.edu/infocenter/vitamins/vitaminK/ . Retrieved 01-10-2011. Warner, E.D.; Brinkhous, K. M.; Smith, H. P. (1938). Proceedings of the Society of Experimental Biology and Medicine 37: 628. Stafford, D.W. (2005), “The vitamin K cycle.”. Journal of Thrombosis and Haemostasis, 3: 1873–1878. Saxena S.P.; Israels, E.D.; Israels L.G. (2001). "Novel vitamin K-dependent pathways regulating cell survival.". Apoptosis 6 (1-2): 57–68. Nimptsch K, Rohrmann S, Linseisen J (2008). "Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition. (EPIC-Heidelberg)". Am. J. Clin. Nutr. 87 (4): 985–92. Brown, S.E., "Key vitamins for bone health — vitamins K1 and K2" . www.womentowomen.com . http://www.womentowomen.com/bonehealth/keynutrients-vitamink.aspx. Retrieved Jan., 10 2011. Nimptsch K, Rohrmann S, Linseisen J (2008). "Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition. (EPIC-Heidelberg)". Am. J. Clin. Nutr. 87 (4): 985–92. Allison (2001). "The possible role of vitamin K deficiency in the pathogenesis of Alzheimer's disease and in augmenting brain damage associated with cardiovascular disease.". Medical hypotheses 57 (2): 151–5. Habu, D., (2004) "Role of Vitamin K2 in the Development of Hepatocellular Carcinoma in Women With Viral Cirrhosis of the Liver.". JAMA, 292 (3): 358-361. Bellido-Martin, L. (2008) "Vitamin K-dependent actions of Gas6.". Vitam. Horm. 78:185-209. Hendler S.S., Rorvik D.R., eds. (2001) “PDR for Nutritional Supplements.”. Montvale: Medical Economics Company. |
Write a comment:
|
