B vitamins
<p><b >B vitamins</b> are a group of water-soluble <a href="http://en.wikipedia.org/wiki/Vitamin" title="Vitamin" >vitamins</a> that play important roles in <a href="http://en.wikipedia.org/wiki/Cell_(biology)" title="Cell (biology)" >cell</a> <a href="http://en.wikipedia.org/wiki/Metabolism" title="Metabolism" >metabolism</a>. </p>
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The B vitamins were once thought to be a single vitamin, referred to as <b >vitamin B</b> (much as people refer to <a href="http://en.wikipedia.org/wiki/Vitamin_C" title="Vitamin C" >vitamin C</a>). </p>
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Later research showed that they are <a href="http://en.wikipedia.org/wiki/Chemical" title="Chemical" class="mw-redirect" >chemically</a> distinct vitamins that often coexist in the same foods. In general, supplements containing all eight are referred to as a <b >vitamin B complex</b>. </p>
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Individual B vitamin supplements are referred to by the specific name of each vitamin (e.g., B<sub >1</sub>, B<sub >2</sub>, B<sub >3</sub> etc.).
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<ul >
<li ><b>Vitamin B<sub >1</sub></b> (<a href="http://en.wikipedia.org/wiki/Thiamine" title="Thiamine" >thiamine</a>)</li>
<li ><b>Vitamin B<sub >2</sub></b> (<a href="http://en.wikipedia.org/wiki/Riboflavin" title="Riboflavin" >riboflavin</a>)</li>
<li ><b>Vitamin B<sub >3</sub></b> (<a href="http://en.wikipedia.org/wiki/Niacin" title="Niacin" >niacin</a> or <a href="http://en.wikipedia.org/wiki/Niacinamide" title="Niacinamide" class="mw-redirect" >niacinamide</a>)</li>
<li ><b>Vitamin B<sub >5</sub></b> (<a href="http://en.wikipedia.org/wiki/Pantothenic_acid" title="Pantothenic acid" >pantothenic acid</a>)</li>
<li ><b>Vitamin B<sub >6</sub></b> (<a href="http://en.wikipedia.org/wiki/Pyridoxine" title="Pyridoxine" >pyridoxine</a>, <a href="http://en.wikipedia.org/wiki/Pyridoxal" title="Pyridoxal" >pyridoxal</a>, or <a href="http://en.wikipedia.org/wiki/Pyridoxamine" title="Pyridoxamine" >pyridoxamine</a>, or <a href="http://en.wikipedia.org/wiki/Pyridoxine_hydrochloride" title="Pyridoxine hydrochloride" class="mw-redirect" >pyridoxine hydrochloride</a>)</li>
<li ><b>Vitamin B<sub >7</sub></b> (<a href="http://en.wikipedia.org/wiki/Biotin" title="Biotin" >biotin</a>)</li>
<li ><b>Vitamin B<sub >9</sub></b> (<a href="http://en.wikipedia.org/wiki/Folic_acid" title="Folic acid" >folic acid</a>)</li>
<li ><b>Vitamin B<sub >12</sub></b> (various <a href="http://en.wikipedia.org/wiki/Cobalamin" title="Cobalamin" class="mw-redirect" >cobalamins</a>; commonly <a href="http://en.wikipedia.org/wiki/Cyanocobalamin" title="Cyanocobalamin" >cyanocobalamin</a> in vitamin supplements)</li>
</ul>
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The B vitamins are necessary to:</p>
<ul >
<li >Support and increase the rate of <a href="http://en.wikipedia.org/wiki/Metabolism" title="Metabolism" >metabolism</a><sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-0" >[1]</a></sup></li>
<li >Maintain healthy skin, hair and <a href="http://en.wikipedia.org/wiki/Muscle_tone" title="Muscle tone" >muscle tone</a><sup id="cite_ref-1" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-1" >[2]</a></sup><sup id="cite_ref-2" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-2" >[3]</a></sup></li>
<li >Enhance <a href="http://en.wikipedia.org/wiki/Immune_system" title="Immune system" >immune</a> and <a href="http://en.wikipedia.org/wiki/Nervous_system" title="Nervous system" >nervous system</a> function<sup id="cite_ref-3" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-3" >[4]</a></sup><sup id="cite_ref-4" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-4" >[5]</a></sup></li>
<li >Promote <a href="http://en.wikipedia.org/wiki/Cell_growth" title="Cell growth" >cell growth</a> and <a href="http://en.wikipedia.org/wiki/Cell_division" title="Cell division" >division</a>, including that of the <a href="http://en.wikipedia.org/wiki/Red_blood_cell" title="Red blood cell" >red blood cells</a> that help prevent <a href="http://en.wikipedia.org/wiki/Anemia" title="Anemia" >anemia</a></li>
<li ></li>
<li >Reduce the risk of <a href="http://en.wikipedia.org/wiki/Pancreatic_cancer" title="Pancreatic cancer" >pancreatic cancer</a> - one of the most lethal forms of cancer<sup id="cite_ref-5" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-5" >[6]</a></sup> - when consumed in food, but not when ingested in vitamin tablet form.<sup id="cite_ref-6" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-6" >[7]</a></sup><sup id="cite_ref-7" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-7" >[8]</a></sup></li>
<li ></li>
</ul>
<p >All B vitamins are water-soluble, and are dispersed throughout the body. Most of the B vitamins must be replenished regularly, since any excess is excreted in the <a href="http://en.wikipedia.org/wiki/Urine" title="Urine" >urine</a>.<sup id="cite_ref-8" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-8" >[9]</a></sup> This can result in the urine produced being a bright green-yellow colour.</p>
<p>
B vitamins have also been hypothesized to reduce the symptoms of <a href="http://en.wikipedia.org/wiki/Attention_deficit_hyperactivity_disorder" title="Attention deficit hyperactivity disorder" >attention deficit hyperactivity disorder</a>.<sup id="cite_ref-9" class="reference" ><a href="http://en.wikipedia.org/wiki/Vitamin_B_complex#cite_note-9" >[10]</a></sup>
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