taurine adj : of or relating to or resembling a bull n : a colorless crystalline substance obtained from the bile of mammals

English

Etymology 1

From taurinus, from taurus.

Pronunciation

• /ˈtɔ:raɪn/

Adjective

1. Pertaining to a bull; bull-like.

Etymology 2

From taurocholic + -ine.

Pronunciation

• /ˈtɔ:ri:n/

Noun

1. An amino-sulfonic acid, NH2CH2CH2SO3H, that has regulatory functions in mammals.

Taurine, or 2-aminoethanesulfonic acid, is an organic acid. It is also a major constituent of bile and can be found in lower amounts in the tissues of many animals including humans. Taurine is a derivative of the sulfur-containing (sulfhydryl) amino acid, cysteine. Taurine is the only known naturally occurring sulfonic acid.

Taurine is named after the Latin taurus, which means bull or ox, as it was first isolated from ox bile in 1827 by Austrian scientists Friedrich Tiedemann and Leopold Gmelin. It is often called an amino acid, even in scientific literature, but as it lacks a carboxyl group it is not strictly an amino acid. It does contain a sulfonate group and may be called an amino sulfonic acid. Small polypeptides have been identified which contain taurine but to date no aminoacyl tRNA synthetase has been identified as specifically recognizing taurine and capable of incorporating it onto a tRNA.

Physiological roles

Conjugated via its amino terminal group with chenodeoxycholic acid and cholic acid to form the bile salts sodium taurochenodeoxycholate and sodium taurocholate. The low pKa (1.5) of taurine's sulfonic acid group ensures that this moiety is negatively charged in the pH ranges normally found in the intestinal tract and thus improves the surfactant properties of the cholic acid conjugate, which can be found in many energy drinks today. Taurine has also been implicated in a wide array of other physiological phenomena including inhibitory neurotransmission, long-term potentiation in the striatum/hippocampus, membrane stabilization, feedback inhibition of neutrophil/macrophage respiratory bursts, adipose tissue regulation, calcium homeostasis and recovery from osmotic shock.

Prematurely born infants who lack the enzymes needed to convert cystathionine to cysteine may become deficient in taurine. Thus, taurine is a dietary essential nutrient in these individuals and is often added to many infant formulas as a measure of prudence. There is also evidence that taurine is beneficial for adult human blood pressure and possibly, the alleviation of other cardiovascular ailments.

Obese mice demonstrate reduced blood levels of taurine, which may promote further weight gain, and taurine supplementation prevented obesity in mice fed a high-fat, low-taurine diet. Recent studies have also 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. Taurine levels were found to be significantly lower in vegans than in a control group on a standard American diet. Plasma taurine was 78% of control values, and urinary taurine 29%.

According to some animal studies, taurine produced an anxiolytic-like effect in mice and may act as a modulator or anti-anxiety agent in the central nervous system.

In recent years, taurine has become a common ingredient in energy drinks. Taurine is often used in combination with bodybuilding supplements such as creatine and anabolic steroids, partly due to recent findings in mice that taurine alleviates muscle fatigue in strenuous workouts and raises exercise capacity. Taurine is also used in some contact lens solutions.

Taurine has also been shown in diabetic rats to decrease weight and decrease blood sugar.

Taurine and cats

Taurine is essential for cat health, as cats cannot synthesize the compound. The absence of taurine causes a cat's retina to slowly degenerate, causing eye problems and (eventually) irreversible blindness as well as hair loss and tooth decay. This condition is called central retinal degeneration (CRD). In addition, taurine deficiency can cause feline dilated cardiomyopathy, and supplementation can reverse left ventricular systolic dysfunction. Taurine is now a requirement of the Association of American Feed Control Officials (AAFCO) and any dry or wet food product labeled approved by the AAFCO should have a minimum of 0.1% taurine.

Taurine and bird development

Recent research has provided evidence that taurine is essential in early bird development of passerines. 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.

Synthesis and production

In 1993, approximately 5,000–6,000 t of taurine was produced; 50% for pet food manufacture, 50% in pharmaceutical applications. Another approach is the reaction of aziridine with sulfurous acid. This leads directly to taurine.

As a functional food

Taurine is used as a functional food in many energy drinks and energy products (and more recently, in a chocolate bar).

Despite being present in many energy drinks, 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 skeletal muscles.

References

External links

• BBC report on possible uses of taurine and alcohol damage - 2005
• Taurine Rules - energy drink review blog