{"id":900,"date":"2017-10-26T17:00:39","date_gmt":"2017-10-26T17:00:39","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/sunynutrition\/?post_type=chapter&p=900"},"modified":"2017-11-14T17:29:41","modified_gmt":"2017-11-14T17:29:41","slug":"12-5-vitamin-k","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-herkimer-nutritionflex\/chapter\/12-5-vitamin-k\/","title":{"raw":"12.5 Vitamin K","rendered":"12.5 Vitamin K"},"content":{"raw":"
\r\n\r\nThere are 3 forms of vitamin K. Phylloquinone (K1), the plant form of vitamin K, is the primary dietary form of vitamin K. Its structure is shown below.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"800\"]\"\" Figure 12.51 Structure of phylloquinone (K1), the 3 outside of the brackets indicates that the structural unit inside the brackets is repeated 3 times1<\/sup>[\/caption]\r\n\r\n<\/div>\r\nGreen leafy vegetables, broccoli, Brussels sprouts, and asparagus are foods that are good sources of phylloquinone2<\/sup>.\r\n\r\nAnother form of vitamin K, menaquinone (K2), is synthesized by bacteria in the colon. Menaquinone comprises ~10% of absorbed vitamin K every day and can also be found in small amounts in animal products. Its structure is shown below3<\/sup>.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"800\"]\"\" Figure 12.52 Structure of menaquinone (K2). Menaquinones have side chains of varying length4<\/sup>[\/caption]\r\n\r\n<\/div>\r\nIn the structure above, if it was menaquinone-8, there would be 7 (8-1) repeating units of the structure inside the brackets above.\r\n\r\nThe synthetic form of vitamin K is menadione (K3), whose structure is shown below.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"517\"]\"\" Figure 12.53 Structure of menadione (K3)5<\/sup>[\/caption]\r\n\r\n<\/div>\r\nA tail, similar to the one found in menaquinone, has to be added to menadione for it to be biologically active.\r\n\r\nVitamin K is absorbed like other fat-soluble substances. Approximately 80% of phylloquinone and menaquinone are incorporated into chylomicrons and stored primarily in the liver2,6. Once metabolized, vitamin K is primarily excreted via bile in the feces, with a lesser amount excreted in urine6.\r\n\r\nSubsections:\r\n\r\n12.51 Vitamin K Functions<\/a>\r\n\r\n12.52 Vitamin K Deficiency & Toxicity<\/a>\r\n\r\nReferences & Links<\/b>\r\n\r\n1. http:\/\/en.wikipedia.org\/wiki\/File:Phylloquinone_structure.svg\r\n\r\n2. McGuire M, Beerman KA. (2011) Nutritional sciences: From fundamentals to food. Belmont, CA: Wadsworth Cengage Learning.\r\n\r\n3. Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw's perspectives in nutrition. New York, NY: McGraw-Hill.\r\n\r\n4. http:\/\/en.wikipedia.org\/wiki\/File:Menaquinone.svg\r\n\r\n5. http:\/\/en.wikipedia.org\/wiki\/File:Menadione.png\r\n\r\n6. Gropper SS, Smith JL, Groff JL. (2008) Advanced nutrition and human metabolism. Belmont, CA: Wadsworth Publishing.\r\n\r\n<\/div>","rendered":"
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There are 3 forms of vitamin K. Phylloquinone (K1), the plant form of vitamin K, is the primary dietary form of vitamin K. Its structure is shown below.<\/p>\n

\n
\"\"<\/p>\n

Figure 12.51 Structure of phylloquinone (K1), the 3 outside of the brackets indicates that the structural unit inside the brackets is repeated 3 times1<\/sup><\/p>\n<\/div>\n<\/div>\n

Green leafy vegetables, broccoli, Brussels sprouts, and asparagus are foods that are good sources of phylloquinone2<\/sup>.<\/p>\n

Another form of vitamin K, menaquinone (K2), is synthesized by bacteria in the colon. Menaquinone comprises ~10% of absorbed vitamin K every day and can also be found in small amounts in animal products. Its structure is shown below3<\/sup>.<\/p>\n

\n
\"\"<\/p>\n

Figure 12.52 Structure of menaquinone (K2). Menaquinones have side chains of varying length4<\/sup><\/p>\n<\/div>\n<\/div>\n

In the structure above, if it was menaquinone-8, there would be 7 (8-1) repeating units of the structure inside the brackets above.<\/p>\n

The synthetic form of vitamin K is menadione (K3), whose structure is shown below.<\/p>\n

\n
\"\"<\/p>\n

Figure 12.53 Structure of menadione (K3)5<\/sup><\/p>\n<\/div>\n<\/div>\n

A tail, similar to the one found in menaquinone, has to be added to menadione for it to be biologically active.<\/p>\n

Vitamin K is absorbed like other fat-soluble substances. Approximately 80% of phylloquinone and menaquinone are incorporated into chylomicrons and stored primarily in the liver2,6. Once metabolized, vitamin K is primarily excreted via bile in the feces, with a lesser amount excreted in urine6.<\/p>\n

Subsections:<\/p>\n

12.51 Vitamin K Functions<\/a><\/p>\n

12.52 Vitamin K Deficiency & Toxicity<\/a><\/p>\n

References & Links<\/b><\/p>\n

1. http:\/\/en.wikipedia.org\/wiki\/File:Phylloquinone_structure.svg<\/p>\n

2. McGuire M, Beerman KA. (2011) Nutritional sciences: From fundamentals to food. Belmont, CA: Wadsworth Cengage Learning.<\/p>\n

3. Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw’s perspectives in nutrition. New York, NY: McGraw-Hill.<\/p>\n

4. http:\/\/en.wikipedia.org\/wiki\/File:Menaquinone.svg<\/p>\n

5. http:\/\/en.wikipedia.org\/wiki\/File:Menadione.png<\/p>\n

6. Gropper SS, Smith JL, Groff JL. (2008) Advanced nutrition and human metabolism. Belmont, CA: Wadsworth Publishing.<\/p>\n<\/div>\n\n\t\t\t

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