Vitamin D helps you absorb calcium, Vitamin K tells your body where to put it
Vitamin K is well known as a blood clotting agent, without which, an injury could cause us to bleed to death. In fact, vitamin K was named after the German word "koagulation". Most people get sufficient dietary K to maintain adequate blood clotting. HOWEVER, they do NOT obtain enough or the right type of vitamin K to perform the more recently discovered important functions/roles of vitamin K, including:
Fat-Soluble vitamin K exists in two basic natural forms, K1 and K2. Each now found to have quite DIFFERENT physiological functions:
(1) Vitamin K1 (PHYLLOQUINONE) - ~90% of vitamin K intake in typical Western diet
(2) Vitamin K2 (E.g. MENAQUINONE 4, 7,8,9 thru 14). ~10% of vitamin K intake in typical Western diet found in primarily fermented foods and aged cheeses; also produced by gut bacteria;
K2 is preferentially used by vessel walls, bones, and tissues other than your liver
Spronk, H.M., Soute, B.A., Schurgers, L.J., Thijssen, H.H., De Mey, J.G., Vermeer, C., 2003. Tissue-specific utilization of menaquinone-4 results in the prevention of arterial calcification in warfarin-treated rats. J. Vasc. Res. 40(6), pp 531-537.
K2 has several subforms (with repeating 5-carbon units in the side chain of the molecule) -denoted as menaquinone-n or MK-n, where n is the number of 5-carbon units) :
MK-7, 8, 9 and 10 come from bacterial fermentation.
Beneficial gut bacteria (called probiotics) produce several subforms of vitamin K2. These lactic acid bacteriapartially contribute to body's K-status as the K2 is absorbed in small amounts from the distal small intestine (ileum).
Conly, J; Stein K (1994). "Reduction of vitamin K2 concentrations in human liver associated with the use of broad spectrum antimicrobials". Clinical and investigative medicine. Médecine clinique et experimentale 17(6): 531-539. PubMed
K2 subforms found in animal foods(especially organs and pastured dairy), curds and fermented foods. Many of them containing saturated fat:
Amount of K2 in fermented Foods is dependent on type of K2-producing bacteria used for fermentation:
Cheeses - E.g.Swiss Emmental cheese and Norwegian Jarlsberg cheese use the genus Proprionibacterium (creates CO2 bubbles that make the familiar holes in the cheese). These bacteria can make large amounts of vitamin K2 in the form of MK-9
Fermented soy foods - the most important K2-producing bacteria are Bacillusgenus, which create the MK-7 subform of K2. Studies demonstrate that higher blood levels of MK-7 (obtained by consuming Bacillus in fermented soy) are associated with lower risk of hip fracture in older Japanese women. Natto has been an integral part of Asian cuisine for many centuries. Bacillus (E.g. B. subtilis var. natto strain used in natto production) has the potential ability to stay alive for several days in the lower intestine after consumption providing the body with MK-7.
Newborns are sometimes given K1 shots to prevent intracranial hemorrhage - to tide them over until at just over a week old, their intestinal bacteria produce K2 and the the infant has been ingesting K in colostrum, breastmilk or non-soy based formula (contains more K than breastmilk);
Under ideal circumstances, gut bacteriaor enzymes in cell metabolism can convert K1 from food and convert it into K2 - maintaining an optimal balance between the K1 and K2 forms of this vitamin. The mammary glands are especially efficient at producing K2 from K1, presumeably to supply growing breast-fed infants.
Certain factors can interfere with the K1 to K2 conversion:
Tsugawa N, Shiraki M, et al. Am J Clin Nutr 2006
The body's K1 => K2 conversion ratio is said to be about 10:1 and is enhanced by the presence of fat
Although animals can convert K1Ã K2 , evidence suggests that the human diet needs to contain preformed K2 for optimal health:
Unden, G. and J. Bongaerts (1997). "Alternative respiratory pathways of Escherichia coli: energetics and transcriptional regulation in response to electron acceptors." Biochim Biophys Acta 1320(3): 217-234.
Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MHJ, van der Meer IM, Hofman A and Witteman JCM. "Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: The Rotterdam Study" November 2004; J Nutr 134:3100-3105
Schurgers LJ, Vermeer C., 2000. Determination of Phylloquinone and Menaquinones in Food. Haemostasis. 2000; 30: 298-307
The study showing vitamin K2′s dramatic role in treating prostate cancer, revealed that vitamin K1 had no effect.
Study by European Prospective Investigation into Cancer and Nutrition (EPIC), Heidelburg, Germany
K2 is better absorbed than K1 and remains active much longer
Schurgers LJ, Teunissen KJ 2007
Gijsbers et al., 1996; Garber et al, 1999
Phylloquinones present in green leafy vegetables are tightly bound to the thylakoid membranes in plant chloroplasts, and are not well solubilized and absorbed without the concomitant intake of fat, which stimulates bile secretion
Gijsbers et al., 1996; Schurgers and Vermeer, 2000; Schurgers, 2002; Vermeer et al., 2004
K2 is carried in the lymph in mixed micelles composed of bile salts, and subsequently released into the circulation.
Vermeer, 2003
Schurgers and Vermeer, 2000; Schurgers, 2002.
Absorption of vitamin K ( as other fat-soluble vitaminsE.g. A, D and E) depends on healthy liver, gallbladder and digestive function. Deficiency is more likely in people with digestive problems such as pancreatic disease, celiac disease, irritable bowel syndrome (IBS), ulcerative colitis, Crohn's disease or those who have had intestinal bypass surgery.
Binkley NC, Grueger DC, Kawahara TN, Engelke JA, Chappell RJ, Suttie JW. 2002. A high phylloquinone intake is required to achieve maximal osteocalcin gamma-carboxylation. Am J Clin Nutr. 2002; 76: 1055-60.
Garber AK, Binkley NC, Krueger DC, Suttie JW. 1999. Comparison of Phylloquinone Bioavailability from Food Sources or a Supplement in Human Subjects. J Nutr. 1999; 129: 1201-1203.
Gijsbers BLMG, Jie K-SG, Vermeer C. 1996. Effect of food composition on vitamin K absorption in human volunteers. Br J Nutr. 1996; 76: 223-229.
McKeown NM, Jacques PF, Gundberg CM, Peterson JW, Tucker KL, Kiel KP, Wilson PWF, Booth SL.2002. Dietary and nondietary determinants of vitamin K biochemical measures in men and women.J Nutr. 2002; 132(6): 1329-1334.
Schurgers LJ, Vermeer C., 2000. Determination of Phylloquinone and Menaquinones in Food. Haemostasis. 2000; 30: 298-307
.Schurgers LJ, Teunissen KJF, Hamulyak K, Knapen MHJ, Hogne V, Vermeer C.2007. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2006; [Epub ahead of print].
Vermeer, C. 2003. Pharmacokinetics of vitamin K2 after ingestion of natto food and natto capsules. (Natto-1 Study). VitaK/University of Maastricht. Research Project, July 25, 2003.
Vermeer, C., Shearer, M.J., Zittermann, A., Bolton-Smith, C., Szulc, P., Hodges, S., Walter, P., Rambeck, W., Stocklin, E., Weber, P. 2004. Beyond deficiency: Potential benefits of increased intakes of vitamin K for bone and vascular health. Eur. J. Nutr. 43(6), 325-335.
Although vitamin K is a fat-soluble vitamin, the body stores very little of it, and its stores are rapidly depleted without regular dietary intake
Unlike the other fat-soluble nutrients(vitamins A, D and E), vitamin K is NOT significantly stored in the body. Beneficial bacteria(called probiotics) produce vitamin K2, but absorption of this source is poor (especially in those with digestive problems) and most people are short of these beneficial bacteria. Vitamin K must be provided daily to avoid a K- deficiency, which can develop in as few as 7 days on a vitamin K-deficient diet.
Israels LG, Israels ED, et al, The riddle of vitamin K1 deficit in the newborn.Semin Perinatol. 1997 Feb;21(1):90-6.)
Vitamin K cycle conserves K. Allowing a small amount of vitamin K to be recycled many times in the gamma-carboxylation of proteins. (see Health Benefits of Vitamin K). Warfarin/Coumadin blocks this recycling, effectively creating a functional K-deficiency
Linus Pauling Institute: http://lpi.oregonstate.edu/infocenter/vitamins/vitaminK/
Weston A.Price Foundation: http://www.westonaprice.org/fat-soluble-activators/x-factor-is-vitamin-k2
Vitamin K2 as source of vitamin K added for nutritional purposes to foodstuffs http://www.efsa.europa.eu/en/scdocs/doc/nda_op_ej822_vit_k2_en.pdf?ssbinary=true