Vitamins and Minerals
<p >An <b>essential nutrient</b> is a <a href="http://en.wikipedia.org/wiki/Nutrient" title="Nutrient" >nutrient</a> required for normal body functioning that either cannot be synthesized by the body at all, or cannot be synthesized in amounts adequate for good health (e.g.<a href="http://en.wikipedia.org/wiki/Niacin" title="Niacin" >niacin</a>, <a href="http://en.wikipedia.org/wiki/Choline" title="Choline" >choline</a>), and thus must be obtained from a <a href="http://en.wikipedia.org/wiki/Diet_(nutrition)" title="Diet (nutrition)" >dietary</a> source. </p>
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Essential nutrients are also defined by the collective physiological evidence for their importance in the diet, as represented in e.g. US government approved tables for <a href="http://en.wikipedia.org/wiki/Dietary_Reference_Intake" title="Dietary Reference Intake" >Dietary Reference Intake</a>.<sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Essential_nutrient#cite_note-0" >[1]</a></sup></p>
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Some categories of essential nutrients include <a href="http://en.wikipedia.org/wiki/Vitamin" title="Vitamin" >vitamins</a>, <a href="http://en.wikipedia.org/wiki/Dietary_minerals" title="Dietary minerals" class="mw-redirect" >dietary minerals</a>, <a href="http://en.wikipedia.org/wiki/Essential_fatty_acid" title="Essential fatty acid" >essential fatty acids</a>, and <a href="http://en.wikipedia.org/wiki/Essential_amino_acid" title="Essential amino acid" >essential amino acids</a>. </p>
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Different species have very different essential nutrients. For example, most mammals synthesize their own <a href="http://en.wikipedia.org/wiki/Ascorbic_acid" title="Ascorbic acid" >ascorbic acid</a>, and it is therefore not considered an essential nutrient for such species.
It is, however, an essential nutrient for human beings, who require external sources of ascorbic acid (known as Vitamin C in the context of nutrition).</p>
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<h3 >Vitamins and minerals</h3>
<div class="rellink relarticle mainarticle" >Main articles: <a href="http://en.wikipedia.org/wiki/Vitamins" title="Vitamins" class="mw-redirect" >Vitamins</a> and <a href="http://en.wikipedia.org/wiki/Minerals" title="Minerals" class="mw-redirect" >Minerals</a></div>
<p >Vitamins are materials required for normal <a href="http://en.wikipedia.org/wiki/Metabolism" title="Metabolism" >metabolism</a> but which the body cannot manufacture itself and which must therefore come from soil. Vitamins come from a number of sources including fresh fruit and vegetables (<a href="http://en.wikipedia.org/wiki/Vitamin_C" title="Vitamin C" >Vitamin C</a>), <a href="http://en.wikipedia.org/wiki/Carrot" title="Carrot" >carrots</a>, <a href="http://en.wikipedia.org/wiki/Liver_(food)" title="Liver (food)" >liver</a> (<a href="http://en.wikipedia.org/wiki/Vitamin_A" title="Vitamin A" >Vitamin A</a>), cereal bran, bread, liver e ( B vitamins), fish liver oil (<a href="http://en.wikipedia.org/wiki/Vitamin_D" title="Vitamin D" >Vitamin D</a>) and fresh green vegetables (<a href="http://en.wikipedia.org/wiki/Vitamin_K" title="Vitamin K" >Vitamin K</a>). </p>
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Many minerals are also essential in small quantities including <a href="http://en.wikipedia.org/wiki/Iron" title="Iron" >iron</a>, <a href="http://en.wikipedia.org/wiki/Calcium" title="Calcium" >calcium</a>, <a href="http://en.wikipedia.org/wiki/Magnesium" title="Magnesium" >magnesium</a> and
<a href="http://en.wikipedia.org/wiki/Sulphur" title="Sulphur" class="mw-redirect" >sulphur</a>; and in very small quantities <a href="http://en.wikipedia.org/wiki/Copper" title="Copper" >copper</a>, <a href="http://en.wikipedia.org/wiki/Zinc" title="Zinc" >zinc</a> and <a href="http://en.wikipedia.org/wiki/Selenium" title="Selenium" >selenium</a>. The micronutrients, minerals, and vitamins<sup id="cite_ref-5" class="reference" ><a href="http://en.wikipedia.org/wiki/Cooking#cite_note-5" >[6]</a></sup> in fruit and vegetables may be destroyed or eluted by cooking. </p>
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Vitamin C is especially prone to oxidation during cooking and may be completely destroyed by protracted cooking.<sup id="cite_ref-news.bbc.co.uk_6-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Cooking#cite_note-news.bbc.co.uk-6" >[7]</a></sup></p>
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