Vitamin K
<p ><b>Vitamin K</b> is a group of structurally similar, fat-soluble <a href="http://en.wikipedia.org/wiki/Vitamin" title="Vitamin" >vitamins</a> that are needed for the <a href="http://en.wikipedia.org/wiki/Posttranslational_modification" title="Posttranslational modification" >posttranslational modification</a> of certain proteins required for blood <a href="http://en.wikipedia.org/wiki/Coagulation" title="Coagulation" >coagulation</a> and in <a href="http://en.wikipedia.org/wiki/Metabolic_pathway" title="Metabolic pathway" >metabolic pathways</a> in bone and other tissue. They are 2-<a href="http://en.wikipedia.org/wiki/Methyl" title="Methyl" class="mw-redirect" >methyl</a>-<a href="http://en.wikipedia.org/wiki/1,4-naphthoquinone" title="1,4-naphthoquinone" class="mw-redirect" >1,4-naphthoquinone</a> (3-) <a href="http://en.wikipedia.org/wiki/Derivative_(chemistry)" title="Derivative (chemistry)" >derivatives</a>. This group of vitamins includes two natural <a href="http://en.wikipedia.org/wiki/Vitamer" title="Vitamer" >vitamers</a>: vitamin K<sub >1</sub> and vitamin K<sub >2</sub>.<sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-0" >[1]</a></sup> The three basic forms of Vitamin K are K1, K2, and K3.<sup id="cite_ref-ACC_1-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-ACC-1" >[2]</a></sup></p>
<p>
Vitamin K<sub >1</sub>, also known as <a href="http://en.wikipedia.org/wiki/Phylloquinone" title="Phylloquinone" >phylloquinone</a> or phytomenadione (also called phytonadione), is synthesized by plants, and is found in highest amounts in <a href="http://en.wikipedia.org/wiki/Leaf_vegetable" title="Leaf vegetable" >green leafy vegetables</a> because it is directly involved in photosynthesis.</p>
<p>
Three synthetic types of vitamin K are known: vitamins K<sub >3</sub>, K<sub >4</sub>, and K<sub >5</sub>. </p>
<p>
Although the natural K<sub >1</sub> and K<sub >2</sub> forms are nontoxic, the synthetic form K<sub >3</sub>(menadione) has shown toxicity.<sup id="cite_ref-Higdon_2-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Higdon-2" >[3]</a></sup></p>
<p>
Vitamin K<sub >2</sub> (MK4, but not MK7 or vitamin K<sub >1</sub>) has also been shown to prevent bone loss and/or fractures in the following circumstances:</p>
<ul >
<li >caused by corticosteroids (e.g., prednisone, dexamethasone, prednisolone),<sup id="cite_ref-Inoue_2001_11.E2.80.9318_16-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Inoue_2001_11.E2.80.9318-16" >[17]</a></sup><sup id="cite_ref-Sasaki_2005_41.E2.80.9347_17-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Sasaki_2005_41.E2.80.9347-17" >[18]</a></sup><sup id="cite_ref-Yonemura_2004_53.E2.80.9360_18-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Yonemura_2004_53.E2.80.9360-18" >[19]</a></sup><sup id="cite_ref-Yonemura_2000_123.E2.80.93128_19-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Yonemura_2000_123.E2.80.93128-19" >[20]</a></sup></li>
<li >anorexia nervosa,<sup id="cite_ref-Iketani_2003_259.E2.80.93269_20-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Iketani_2003_259.E2.80.93269-20" >[21]</a></sup></li>
<li >cirrhosis of the liver,<sup id="cite_ref-Shiomi_2002_978.E2.80.93981_21-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Shiomi_2002_978.E2.80.93981-21" >[22]</a></sup></li>
<li >postmenopausal osteoporosis,<sup id="cite_ref-Iwamoto_1999_161.E2.80.93164_15-1" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Iwamoto_1999_161.E2.80.93164-15" >[16]</a></sup><sup id="cite_ref-Cockayne_2006_1256.E2.80.931261_22-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Cockayne_2006_1256.E2.80.931261-22" >[23]</a></sup><sup id="cite_ref-Iwamoto_2000_546.E2.80.93551_23-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Iwamoto_2000_546.E2.80.93551-23" >[24]</a></sup><sup id="cite_ref-Purwosunu_2006_230.E2.80.93234_24-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Purwosunu_2006_230.E2.80.93234-24" >[25]</a></sup><sup id="cite_ref-Shiraki_2000_515.E2.80.93522_25-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Shiraki_2000_515.E2.80.93522-25" >[26]</a></sup><sup id="cite_ref-Ushiroyama_2002_211.E2.80.93221_26-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Ushiroyama_2002_211.E2.80.93221-26" >[27]</a></sup></li>
<li >disuse from stroke,<sup id="cite_ref-Sato_1998_291.E2.80.93296_27-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Sato_1998_291.E2.80.93296-27" >[28]</a></sup></li>
<li ><a href="http://en.wikipedia.org/wiki/Alzheimer%27s_disease" title="Alzheimer's disease" >Alzheimer's disease</a>,<sup id="cite_ref-Sato_2005_61.E2.80.9368_28-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Sato_2005_61.E2.80.9368-28" >[29]</a></sup></li>
<li ><a href="http://en.wikipedia.org/wiki/Parkinson_disease" title="Parkinson disease" class="mw-redirect" >Parkinson disease</a>,<sup id="cite_ref-Sato_2002_114.E2.80.93118_29-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Sato_2002_114.E2.80.93118-29" >[30]</a></sup></li>
<li ><a href="http://en.wikipedia.org/wiki/Primary_biliary_cirrhosis" title="Primary biliary cirrhosis" >primary biliary cirrhosis</a><sup id="cite_ref-Nishiguchi_2001_543.E2.80.93545_30-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Nishiguchi_2001_543.E2.80.93545-30" >[31]</a></sup></li>
<li >and leuprolide treatment (for prostate cancer).<sup id="cite_ref-Somekawa_1999_2700.E2.80.932704_31-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-Somekawa_1999_2700.E2.80.932704-31" >[32]</a></sup></li>
</ul>
<p > </p>
<h2 >Sources</h2>
<table class="wikitable" ><tbody>
<tr>
<th >Food</th>
<th >Serving Size</th>
<th >Vitamin K<sub >1</sub> <sup id="cite_ref-56" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-56" >[57]</a></sup>(μg)</th>
<th >Food</th>
<th >Serving Size</th>
<th >Vitamin K<sub >1</sub> <sup id="cite_ref-57" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_K#cite_note-57" >[58]</a></sup> (μg)</th>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Kale" title="Kale" >Kale</a>, cooked</td>
<td >1/2 cup</td>
<td >531</td>
<td ><a href="http://en.wikipedia.org/wiki/Parsley" title="Parsley" >Parsley</a>, raw</td>
<td >1/4 cup</td>
<td >246</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Spinach" title="Spinach" >Spinach</a>, cooked</td>
<td >1/2 cup</td>
<td >444</td>
<td ><a href="http://en.wikipedia.org/wiki/Spinach" title="Spinach" >Spinach</a>, raw</td>
<td >1 cup</td>
<td >145</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Collards" title="Collards" class="mw-redirect" >Collards</a>, cooked</td>
<td >1/2 cup</td>
<td >418</td>
<td >Collards, raw</td>
<td >1 cup</td>
<td >184</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Swiss_chard" title="Swiss chard" class="mw-redirect" >Swiss chard</a>, cooked</td>
<td >1/2 cup</td>
<td >287</td>
<td >Swiss chard, raw</td>
<td >1 cup</td>
<td >299</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Mustard" title="Mustard" >Mustard</a> greens, cooked</td>
<td >1/2 cup</td>
<td >210</td>
<td >Mustard greens, raw</td>
<td >1 cup</td>
<td >279</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Turnip" title="Turnip" >Turnip</a> greens, cooked</td>
<td >1/2 cup</td>
<td >265</td>
<td >Turnip greens, raw</td>
<td >1 cup</td>
<td >138</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Broccoli" title="Broccoli" >Broccoli</a>, cooked</td>
<td >1 cup</td>
<td >220</td>
<td >Broccoli, raw</td>
<td >1 cup</td>
<td >89</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Brussels_sprouts" title="Brussels sprouts" class="mw-redirect" >Brussels sprouts</a>, cooked</td>
<td >1 cup</td>
<td >219</td>
<td ><a href="http://en.wikipedia.org/wiki/Endive" title="Endive" >Endive</a>, raw</td>
<td >1 cup</td>
<td >116</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Cabbage" title="Cabbage" >Cabbage</a>, cooked</td>
<td >1/2 cup</td>
<td >82</td>
<td ><a href="http://en.wikipedia.org/w/index.php?title=Green_leaf_lettuce&action=edit&redlink=1" class="new" title="Green leaf lettuce (page does not exist)" >Green leaf lettuce</a></td>
<td >1 cup</td>
<td >71</td>
</tr>
<tr>
<td ><a href="http://en.wikipedia.org/wiki/Asparagus" title="Asparagus" >Asparagus</a></td>
<td >4 spears</td>
<td >48</td>
<td ><a href="http://en.wikipedia.org/wiki/Romaine_lettuce" title="Romaine lettuce" >Romaine lettuce</a>, raw</td>
<td >1 cup</td>
<td >57</td>
</tr>
<tr>
<td colspan="6" ><i>Table from "Important information to know when you are taking: Warfarin (Coumadin) and Vitamin K", Clinical Center, National Institutes of Health Drug Nutrient Interaction Task Force.<sup ><a rel="nofollow" class="external autonumber" href="http://www.cc.nih.gov/ccc/patient_education/drug_nutrient/coumadin1.pdf" >[3]</a></sup></i></td>
</tr>
</tbody></table>
<p > </p>