<p><strong>Taurine</strong>, or <strong>2-aminoethanesulfonic acid</strong>, is an <font color="#0066cc">organic acid</font>. It is also a major constituent of <font color="#0066cc">bile</font> and can be found in the lower intestine and in small amounts in the tissues of many animals and in humans as well.<sup class="reference" id="cite_ref-0"><font color="#0066cc"><span>[</span>1<span>]</span></font></sup><sup class="reference" id="cite_ref-1"><font color="#0066cc"><span>[</span>2<span>]</span></font></sup> Taurine is a derivative of the sulfur-containing (<font color="#0066cc">sulfhydryl</font>) <font color="#0066cc">amino acid</font>, <font color="#0066cc">cysteine</font>. Taurine is one of the few known naturally occurring <font color="#0066cc">sulfonic acids</font>.</p><p>Taurine is named after the Latin <em>taurus</em>, which means bull or ox, as it was first isolated from <font color="#0066cc">ox</font> <font color="#0066cc">bile</font> in 1827 by German scientists <font color="#0066cc">Friedrich Tiedemann</font> and <font color="#0066cc">Leopold Gmelin</font>.<sup class="reference" id="cite_ref-2"><font color="#0066cc"><span>[</span>3<span>]</span></font></sup> It is often called an amino acid, even in scientific literature,<sup class="reference" id="cite_ref-3"><font color="#0066cc"><span>[</span>4<span>]</span></font></sup><sup class="reference" id="cite_ref-4"><font color="#0066cc"><span>[</span>5<span>]</span></font></sup><sup class="reference" id="cite_ref-5"><font color="#0066cc"><span>[</span>6<span>]</span></font></sup> but as it lacks a <font color="#0066cc">carboxyl group</font> it is not strictly an amino acid.<sup class="reference" id="cite_ref-6"><font color="#0066cc"><span>[</span>7<span>]</span></font></sup> It does contain a <font color="#0066cc">sulfonate group</font> and may be called an amino sulfonic acid. Small polypeptides have been identified which contain taurine, but to date no <font color="#0066cc">aminoacyl tRNA synthetase</font> has been identified as specifically recognizing taurine and capable of incorporating it onto a <font color="#0066cc">tRNA</font>.<sup class="reference" id="cite_ref-7"><font color="#0066cc"><span>[</span>8<span>]</span></font></sup></p>

<p>The major pathway for mammalian taurine synthesis occurs in the pancreas via the cysteine sulfinic acid pathway. In this pathway, the sulfhydryl group of <font color="#0066cc">cysteine</font> is first oxidized to cysteine sulfinic acid by the enzyme <font color="#0066cc">cysteine dioxygenase</font>. Cysteine sulfinic acid, in turn, is decarboxylated by <font color="#0066cc">sulfinoalanine decarboxylase</font> to form <font color="#0066cc">hypotaurine</font>. It is unclear whether hypotaurine is then spontaneously or enzymatically oxidized to yield taurine.</p><p>Taurine in the pharmaceutical and lab setting is synthesized through a combination of cysteine, <font color="#0066cc">methionine</font>, and <font color="#0066cc">vitamin E</font>. It is naturally produced in the testicles of many mammals. <font color="#0066cc">Urban legends</font> surrounding the source of taurine have included <font color="#0066cc">bull</font> urine extract and bull semen. While it's true that taurine is found in both sources, it is not the source of taurine in the pharmaceutical or <font color="#0066cc">food industry</font>.</p>

<p>Taurine is <font color="#0066cc">conjugated</font> via its amino terminal group with <font color="#0066cc">chenodeoxycholic acid</font> and <font color="#0066cc">cholic acid</font> to form the <font color="#0066cc">bile salts</font> sodium taurochenodeoxycholate and sodium taurocholate. The low <font color="#0066cc">pKa</font> (pKa (1.5) of taurine's sulfonic acid group ensures that this <font color="#0066cc">moiety</font> is negatively charged in the pH ranges normally found in the intestinal tract and thus improves the <font color="#0066cc">surfactant</font> properties of the cholic acid conjugate, which can be found in many <font color="#0066cc">energy drinks</font> today. Taurine crosses the <font color="#0066cc">bloodblood-brain barrier</font><sup class="reference" id="cite_ref-8"><font color="#0066cc"><span>[</span>9<span>]</span></font></sup><sup class="reference" id="cite_ref-9"><font color="#0066cc"><span>[</span>10<span>]</span></font></sup><sup class="reference" id="cite_ref-10"><font color="#0066cc"><span>[</span>11<span>]</span></font></sup> and has been implicated in a wide array of physiological phenomena including inhibitory neurotransmission,<font color="#0066cc">neurotransmission</font>,<sup sup class="reference" id="cite_ref-11"><font color="#0066cc"><span>[</span>12<span>]</span></font></sup> <font color="#0066cc">long-term potentiation</font> in the striatum/hippocampus,<font colorsup class="#0066ccreference"id="cite_ref-12"><span>striatum[</fontspan>13<span>]</<font color="#0066cc"span>hippocampus</fontsup>membrane stabilization,<sup class="reference" id="cite_ref-12"><font color="#0066cc13"><span>[</span>1314<span>]</span></font></sup> <font color="#0066cc">membrane stabilization<feedback inhibition of neutrophil/font>macrophage respiratory burst, adipose tissue regulation and possible prevention of obesity,<sup class="reference" id="cite_ref-1314"><font color="#0066cc"><spanspan>[</span>1415<span>]</span></fontsup></sup> feedback inhibition of <font colorclass="#0066ccreference">neutrophil</font>/<font colorid="#0066cccite_ref-15">macrophage<span>[</fontspan> 16<font color="#0066cc"span>respiratory burst]</font>, <font color="#0066cc"span>adipose</fontsup> tissue regulation and possible prevention of obesitycalcium homeostasis,<sup class="reference" id="cite_ref-14"><font color="#0066cc16"><span>[</span>1517<span>]</span></font></sup>recovery from osmotic shock,<sup class="reference" id="cite_ref-15"><font color="#0066cc17"><span>[</span>1618<span>]</span></font></sup> calcium <font color="#0066cc">homeostasis</font>,protection against glutamate excitotoxicity<sup class="reference" id="cite_ref-1618"><font color="#0066cc"><spanspan>[</span>1719<span>]</span></font></sup> recovery from <font color="#0066cc">osmotic shock</font>,and prevention of epileptic seizures.<sup class="reference" id="cite_ref-1719"><font color="#0066cc"><spanspan>[</span>1820<span>]</span></font></sup> protection It also acts as an antioxidant and protects against glutamate toxicity of various substances (such as lead and cadmium).<font colorsup class="#0066ccreference">excitotoxicity</font><sup class="reference" idid="cite_ref-18"><font color="#0066cc20"><span>[</span>1921<span>]</span></font></sup> and prevention of epileptic seizures.<sup class="reference" id="cite_ref-1921"><font color="#0066cc"><span>span>[</span>2022<span>]</span></fontsup></sup> It also acts as an <font colorclass="reference" id="#0066cccite_ref-22">antioxidant<span>[</fontspan> and protects against toxicity of various substances (such as <font color="#0066cc"23<span>lead]</fontspan> and <font color="#0066cc">cadmium</fontsup>).<sup class="reference" id="cite_ref-20"><font color="#0066cc23"><span>[</span>2124<span>]</span></font></sup>Additionally, supplementation with taurine has been shown to prevent oxidative stress induced by exercise.<sup class="reference" id="cite_ref-21"><font color="#0066cc24"><span>[</span>2225<span>]</span></fontsup></supp><sup class="reference" id="cite_ref-22"p><font color="#0066cc"><span>[</span>23<span>]</span></font></sup><sup class="reference" id="cite_ref-23"><font color="#0066cc"><span>[</span>24<span>]</span></font></sup> AdditionallyIt is believed that prematurely born infants lack the enzymes needed to convert cystathionine to cysteine and may therefore become deficient in taurine. Thus, taurine is thought to be a dietary essential nutrient in these individuals and has been added to many infant formulas as a measure of prudence, supplementation with taurine since the early 1980s. However, this practice has never been shown rigorously studied, and as such it has yet to be proven to prevent oxidative stress induced by exercisebe beneficial, or even necessary.<sup class="reference" id="cite_ref-24"><font color="#0066cc25"><span>[</span>2526<span>]</span></font></sup></p><p>It There is believed also evidence that prematurely born infants lack taurine is beneficial for adult human blood pressure and possibly, the enzymes needed to convert alleviation of other cardiovascular ailments (in humans suffering essential hypertension, taurine supplementation resulted in measurable decreases in blood pressure).<font colorsup class="#0066ccreference" id="cite_ref-26">cystathionine<span>[</fontspan>27<span> to ]<font color="#0066cc"/span>cysteine</fontsup> and may therefore become deficient in taurine. ThusIn a recent 2008 study, taurine is thought has been shown to be a dietary essential nutrient reduce the secretion of apolipoprotein B100 and lipids in these individuals and has been added to many infant formulas as a measure HepG2 cells.<sup class="reference" id="cite_ref-27"><span>[</span>28<span>]</span></sup> High concentrations of prudence, since the early 1980sserum lipids and apolipoprotein B100 (essential structural component of VLDL and LDL) are major risk factors of atherosclerosis and coronary heart disease. HoweverHence, this practice has never been rigorously studied, and as such it has yet to be proven to be it is possible that taurine supplementation is beneficial, or even necessaryfor the prevention of these diseases.<sup class="reference" id="cite_refIn a 2003 study, Zhang et al. have demonstrated the hypocholesterolemic (blood cholesterol-25"><font color=lowering) effect of dietary taurine in young overweight adults. Furthermore, they reported that body weight also reduced significantly in the taurine supplemented group.<sup class="#0066ccreference" id="cite_ref-28"><span>[</span>2629<span>]</span></fontsup>These findings are consistent with animal studies.</supclass="reference" id="cite_ref-29"><span>[</pspan>30<pspan>There is also evidence that taurine is beneficial for adult human <font color="#0066cc"]</span>blood pressure</fontsup> Taurine has also been shown to help people with congestive heart failure by increasing the force and possibly, the alleviation effectiveness of other cardiovascular ailments (in humans suffering essential heart-muscle contractions.<font colorsup class="#0066ccreference"id="cite_ref-30"><span>hypertension[</font>, taurine supplementation resulted in measurable decreases in blood pressure).<sup class="reference" id="cite_ref-26"><font color="#0066cc"span>31<span>[]</span>27<span>]</spansup></fontp></supp> In Taurine levels were found to be significantly lower in vegans than in a recent 2008 study, taurine has been shown to reduce the secretion control group on a standard American diet. Plasma taurine was 78% of <font color="#0066cc">apolipoprotein B100</font> control values, and lipids in HepG2 cellsurinary taurine 29%.<sup class="reference" id="cite_ref-27"><font color="#0066cc31"><span>[</span>2832<span>]</span></fontsup></supp> High concentrations of serum lipids and apolipoprotein B100 (essential structural component of <font color="#0066cc">VLDL</fontp> In the cell, taurine keeps potassium and <font color="#0066cc">LDL</font>) are major risk factors of <font color="#0066cc">atherosclerosis</font> and <font color="#0066cc">coronary heart disease</font>magnesium inside the cell while keeping excessive sodium out. In this sense it works like a diuretic. HenceBut unlike prescription diuretics, it is possible that taurine supplementation is beneficial for not a cellular poison. Because it aids the prevention movement of these diseases. In a 2003 studypotassium, sodium, Zhang et al. have demonstrated and calcium in and out of the hypocholesterolemic (blood cholesterol-lowering) effect of dietary taurine in young overweight adults. Furthermorecell, they reported that body weight also reduced significantly in the taurine supplemented grouphas been used as a supplementation for epileptics as well as for people who have uncontrollable facial twitches.<sup class="reference" id="cite_ref-28"><font color="#0066cc32"><span>[</span>2933<span>]</span></fontsup></supp><p> These findings are consistent with According to animal studies, taurine produces anxiolytic effect and may act as a modulator or anti-anxiety agent in the central nervous system.<sup class="reference" id="cite_ref-29"><font color="#0066cc33"><span>[</span>3034<span>]</span></fontsup></sup> Taurine has also been shown to help people with <font colorclass="reference" id="#0066cccite_ref-34">congestive heart failure<span>[</fontspan>35<span>]</span></sup> by increasing the force and effectiveness of heart-muscle contractions.<sup class="reference" id="cite_ref-30"><font color="#0066cc35"><span>[</span>3136<span>]</span></font></sup></p><p>Taurine levels were found to be significantly lower in is necessary for normal skeletal muscle functioning. This was shown by a 2004 study,<font colorsup class="#0066ccreference" id="cite_ref-36">vegans<span>[</fontspan> than in 37<span>]</span></sup> using mice with a control group on genetic taurine deficiency. They had a standard American diet. Plasma taurine was 78% nearly complete depletion of control values, skeletal and urinary cardiac muscle taurine 29levels. These mice had a reduction of more than 80%of exercise capacity compared to control mice. The authors expressed themselves as &quot;surprised&quot; that cardiac function showed as largely normal (given various other studies about effects of taurine on the heart).<sup class="reference" id="cite_ref-31"><font color="#0066cc"><span>[</span>32<span>]</span></font></sup></p><p>In the cell, Studies have shown that taurine keeps potassium can influence (and magnesium inside the cell while keeping excessive sodium out. In this sense it works like a diuretic. But unlike prescription diuretics, it is not a cellular poison. Because it aids the movement of potassium, sodiumpossibly reverse) defects in nerve blood flow, motor nerve conduction velocity, and calcium nerve sensory thresholds in and out of the cell, taurine has been used as a supplementation for epileptics as well as for people who have uncontrollable facial twitchesexperimental diabetic neuropathic rats.<sup class="reference" id="cite_ref-32PubMed_16624563_37-0"><font color="#0066cc"><span>span>[</span>3338<span>]</span></fontsup></supclass="reference" id="cite_ref-PubMed_11259114_38-0"><span>[</pspan>39<pspan>According to animal studies, taurine produces ]<font color="#0066cc"/span>anxiolytic</fontsup> effect In another study on diabetic rats, taurine significantly decreased weight and may act as a modulator or anti-anxiety agent in the central nervous systemdecreased blood sugar in these animal models.<sup class="reference" id="cite_ref-33"><font color="#0066ccJapanese_rats_39-0"><span>[</span>3440<span>]</span></font></sup><sup class=Likewise, a 2008 study demonstrated that taurine administration to diabetic rabbits resulted in 30% decrease in serum glucose levels.<sup class="reference" id="cite_ref-34"><font color="#0066cc40"><span>[</span>3541<span>]</span></font></sup>According to the single study on human subjects, daily administration of 1.5g taurine had no significant effect on insulin secretion or insulin sensitivity.<sup class="reference" id="cite_ref-35"><font color="#0066cc41"><span>[</span>3642<span>]</span></font></sup></p><p>Taurine However it is necessary for normal skeletal muscle functioningpossible that an effect may occur at higher dosages. This was shown by There is evidence that taurine may exert a 2004 study,beneficial effect in preventing diabetes-associated microangiopathy and tubulointerstitial injury in diabetic nephropathy.<sup class="reference" id="cite_ref-36"><font color="#0066cc42"><span>[</span>3743<span>]</span></fontsup></supclass="reference" id="cite_ref-43"> using mice with a genetic taurine deficiency. They had a nearly complete depletion of skeletal and cardiac muscle <span>[</span>44<span>]</span></sup> Taurine acts as a glycation inhibitor. Studies have shown that taurine levels. These mice treated diabetic rats had a reduction decrease in the formation of more than 80% of exercise capacity compared to control mice. The authors expressed themselves as &quot;surprised&quot; that cardiac function showed as largely normal (given various other studies about effects of taurine on the heart)advanced glycation end products (AGEs) and AGEs content.<sup class="reference" id="cite_ref-44"><span>[</span>45<span>]</pspan><p/sup>Studies have shown that taurine can influence (and possibly reverse) defects in nerve blood flow, motor nerve conduction velocity, and nerve sensory thresholds in experimental diabetic neuropathic rats.<sup class="reference" <sup class="reference" id="cite_ref-PubMed_16624563_37-0"><font color="#0066cc45"><span>[</span>3846<span>]</span></fontsup></supp><sup class="reference" id="cite_ref-PubMed_11259114_38-0"p><font color=Lately, cosmetic compositions containing taurine have been introduced, possibly due to its antifibrotic properties. It has been shown that taurine acts as a TGFB1 inhibitor.<sup class="#0066ccreference"><id="cite_ref-46"><span>[</span>3947<span>]</span></fontsup>It also helps to maintain skin hydration.</sup> In another study on diabetic rats, taurine significantly decreased weight and decreased <font color="#0066cc">blood sugar</font> in these animal models.<sup classclass="reference" id="cite_ref-Japanese_rats_39-0"><font color="#0066cc47"><span>[</span>4048<span>]</span></fontsup></supp> Likewise, a 2008 study demonstrated that taurine administration to diabetic rabbits resulted <p>Taurine is also used in 30% decrease in serum glucose levelssome contact lens solutions.<sup class="reference" id="cite_ref-40"><font color="#0066cc"><span>[</span>41<span>]</span></font></sup> According to the single study on human subjects, daily administration of 1.5g taurine had no significant effect on insulin secretion or insulin sensitivity.<sup class="reference" id="cite_ref-41"><font color="#0066cc"><span>[</span>42<span>]</span></font></sup> However it is possible that an effect may occur at higher dosages. There is evidence that taurine may exert a beneficial effect in preventing diabetes-associated <font color="#0066cc">microangiopathy</font> and tubulointerstitial injury in <font color="#0066cc">diabetic nephropathy</font>.<sup class="reference" id="cite_ref-42"><font color="#0066cc"><span>[</span>43<span>]</span></font></sup><sup class="reference" id="cite_ref-43"><font color="#0066cc"><span>[</span>44<span>]</span></font></sup> Taurine acts as a glycation inhibitor. Studies have shown that taurine treated diabetic rats had a decrease in the formation of <font color="#0066cc">advanced glycation end products</font> (AGEs) and AGEs content.<sup class="reference" id="cite_ref-44"><font color="#0066cc"><span>[</span>45<span>]</span></font></sup><sup class="reference" id="cite_ref-45"><font color="#0066cc"><span>[</span>46<span>]</span></font></sup></p><p>Lately, cosmetic compositions containing taurine have been introduced, possibly due to its <font color="#0066cc">antifibrotic</font> properties. It has been shown that taurine acts as a <font color="#0066cc">TGFB1</font> inhibitor.<sup class="reference" id="cite_ref-46"><font color="#0066cc"><span>[</span>47<span>]</span></font></sup> It also helps to maintain skin hydration.<sup class="reference" id="cite_ref-47"><font color="#0066cc"><span>[</span>48<span>]</span></font></sup></p><p>Taurine is also used in some contact lens solutions.<sup class="reference" id="cite_ref-48"><font color="#0066cc48"><span>[</span>49<span>]</span></font></sup></p><p><font color="#0066cc"></font>&nbsp;</p>

<p>Taurine is an essential dietary requirement for feline health, as cats cannot synthesize the compound. The absence of taurine causes a cat's <font color="#0066cc">retina</font> to slowly degenerate, causing eye problems and (eventually) irreversible blindness &mdash; a condition known as <font color="#0066cc">central retinal degeneration</font> (CRD),<sup class="reference" id="cite_ref-49"><font color="#0066cc"><span>[</span>50<span>]</span></font></sup><sup class="reference" id="cite_ref-50"><font color="#0066cc"><span>[</span>51<span>]</span></font></sup> as well as hair loss and tooth decay. It was discovered in 1987 that taurine deficiency can also cause <font color="#0066cc">feline dilated cardiomyopathy</font>.<sup class="reference" id="cite_ref-51"><font color="#0066cc"><span>[</span>52<span>]</span></font></sup> Unlike CRD, the condition is reversible with supplementation. Taurine is now a requirement of the <font color="#0066cc">Association of American Feed Control Officials</font> (AAFCO) and any dry or wet food product labeled approved by the AAFCO should have a minimum of 0.1% taurine in dry food and 0.2% in wet food.<sup class="reference" id="cite_ref-52"><font color="#0066cc"><span>[</span>53<span>]</span></font></sup></p><p><font color="#0066cc"></font>&nbsp;</p>

<p>Recent research has provided evidence that taurine is essential in early bird development of <font color="#0066cc">passerines</font>. Many passerines, regardless of spider availability, seek out many taurine-rich spiders to feed their young particularly in their youngest stages of life. Researchers later compared the behaviors and development of birds fed a taurine-supplemented diet to a control diet and found that juveniles that were fed taurine-rich diets as neonates were much larger risk takers and more adept at spatial learning tasks.<sup class="reference" id="cite_ref-Arnold2007_53-0"><font color="#0066cc"><span>[</span>54<span>]</span></font></sup></p><p><font color="#0066cc"></font>&nbsp;</p>

<p>In 1993, approximately 5,000&ndash;6,000 t. of taurine was produced; 50% for pet food manufacture, 50% in pharmaceutical applications.<sup class="reference" id="cite_ref-kirk_54-0"><font color="#0066cc"><span>[</span>55<span>]</span></font></sup> Synthetic taurine is obtained from <font color="#0066cc">isethionic acid</font> (2-hydroxyethanesulfonic acid), which in turn is obtained from the reaction of <font color="#0066cc">ethylene oxide</font> with aqueous <font color="#0066cc">sodium bisulfite</font>.<sup class="reference" id="cite_ref-55"><font color="#0066cc"><span>[</span>56<span>]</span></font></sup> Another approach is the reaction of <font color="#0066cc">aziridine</font> with <font color="#0066cc">sulfurous acid</font>. This leads directly to taurine.<sup class="noprint Template-Fact"><span title="This claim needs references to reliable sources since January 2008" style="WHITE-SPACE: nowrap">[<em><font color="#0066cc">citation needed</font></em>]</span></sup></p>

<p>Taurine is used as a <font color="#0066cc">functional food</font> in many <font color="#0066cc">energy drinks</font> and <font color="#0066cc">energy products</font><sup class="reference" id="cite_ref-56"><font color="#0066cc"><span>[</span>57<span>]</span></font></sup> Despite being present in many energy foods, it has not been proven to be energy-giving. A study of mice hereditarily unable to transport taurine suggests that it is needed for proper maintenance and functioning of <font color="#0066cc">skeletal muscles</font>.<sup class="reference" id="cite_ref-57"><font color="#0066cc"><span>[</span>58<span>]</span></font></sup> Additionally, it has been proven effective in removing fatty liver deposits in humans, preventing liver disease, and reducing <font color="#0066cc">cirrhosis</font> in rats.<sup class="reference" id="cite_ref-58"><font color="#0066cc"><span>[</span>59<span>]</span></font></sup><sup class="reference" id="cite_ref-59"><font color="#0066cc"><span>[</span>60<span>]</span></font></sup></p><p><font color="#0066cc"></font>&nbsp;</p>