Taurine (2-aminoethanesulfonic acid) is an organic compound discovered in bull bile in 1827. It is mainly found in different animal tissues, mostly in bile and large intestines. The term 'taurine' has a Latin origin from the word 'taurus' which means bull. Taurine has many functions inside animal bodies like muscle development, cardiovascular functions, and nervous system development, among others. Initially, scientists extracted this compound before the advent of synthetic taurine. However, there are several myths and misconception about taurine products. German scientists Friedrich Tiedemann and Leopold Gmelin were the first to extract taurine from ox bile.
Sources of Taurine
Although initially thought to be exclusively in cow bile, taurine is found in food like meat, seafood, and dairy products. Taurine is low in plant foods. Animal tissues like the human intestine, breast milk, and eye retina have significant levels of taurine. People who eat normal balanced diets have enough taurine (9-400mg per day) in their bodies. Taurine in breast milk is essential since prematurely born babies have low levels of the compound since they lack the necessary enzymes that convert cystathionine to cysteine. For babies who cannot breastfeed, taurine is present as a supplement in infant formula. Most energy drinks, like Red Bull and Monster, contain significant amounts of taurine mixed with other ingredients and therefore should not pass as a taurine supplement. However, these drinks use synthetic taurine not extracted from animal tissue and therefore safe for vegetarians. Several myths emerged claiming that energy drinks contain elements extracted from bull semen. As per the above explanation, these rumors are therefore false.
Taurine Synthesis and Biosynthesis
There are many laboratories all over the world that produce synthetic taurine through the process of ammonolysis. First, ethylene oxide reacts with sodium bisulfite to obtain isethionic acid (2-hydroxyethanesulfonic acid). From here, the process of ammonolysis starts by reacting isethionic acid with ammonia to form taurine. Synthetic taurine is beneficial in the manufacturing of pet food, energy drinks, and pharmaceutical products. Other laboratories, produce taurine by alkylation of ammonia with bromoethane sulfonate salts.
Naturally in living organisms, taurine forms in the semi-essential proteinogenic amino acid called cysteine. The biosynthesis of taurine starts in the pancreas through the cysteine sulfinic acid pathway where cysteine mixes chemically combine with sulfinic acid and oxygen. The enzyme cysteine dioxygenase catalyzes this process to form hypotaurine which is further oxidized by hypotaurine dehydrogenase to form taurine. Some taurine can be synthesized through the transsulfuration pathway where there is an interconversion of cysteine and homocysteine to form cystathionine. The cystathionine is then converted to hypotaurine through the action of cystathionine gamma-lyase, cysteine dioxygenase, and cysteine sulfinic acid decarboxylase enzymes. Just like in the first biosynthesis above, hypotaurine dehydrogenase oxidizes hypotaurine thus forming taurine.
Uses and Benefits of Taurine to Human Health
Naturally, fish and meat contain taurine. This compound is arguably the most important compound in the human body. Taurine improves glucose tolerance, increases insulin action, and as an antioxidant compound it is key for the optimum functioning of body ions such as sodium, magnesium, calcium, and potassium. Extracted animal taurine, in some places, is a key component in the manufacture of other supplements beneficial to the body. Evidence from around the world suggests that high life expectancy is common within populations that take in more taurine, and they also have healthy and more active lifestyles.
In a world where heart diseases and complications are on the increase, most doctors advise people to use taurine in order to reverse cardiovascular disease factors. This compound, in higher concentration, reduces the risk of dying from heart-related complications, lowers the Body Mass Index (BMI), and lowers high blood pressure through the reduction of resistance of blood flow in blood vessel walls, as well as reducing nerve impulses in the brain that contribute to increased blood pressure. Thickening and stiffness of arteries are normally restored through oral supplements of taurine. When levels of taurine in plasma decreases, a person risks having Dilated cardiomyopathy (DCM), a condition where the heart enlarges and becomes incapable of efficiently pumping blood. If not rectified, DCM may also affect the functioning of the liver, lungs, and other body organs. For this reason, Association of American Feed Control Officials (AAFCO) advises that dry and wet food products should have at least 0.1% and 0.2% of taurine respectively.
Studies in both humans and animals show that intake of 3 grams of taurine a day helps the body in fighting obesity by lowering body lipid levels as well as improving glucose tolerance which is useful since most obese people end up suffering from diabetes. This process is true owing to the fact that people with diabetics have lower concentrations of taurine as compared to healthy individuals.
Fighting Parkinson’s Disease
Common tests on patients with Parkinson’s disease reveal low levels of taurine which stimulate stem cells and increases neurons’ life which eventually helps in the growth of brain cells especially in the hippocampus.
As an antioxidant, taurine increases the antioxidant levels in patients with a chronic periodontal disease by enhancing antioxidant enzymes and lipid peroxidation products (TBARS) that fight free radicals and substances that cause an oxidative stress, thus improving the healing process.
Adequate taurine levels prevent age-related eye problems. Naturally, the retina has oxidative-stress-fighting taurine which reduces with age. In children and young people, low taurine levels in the retina may lead to retinal dysfunction and retinal ganglion cell degeneration. Introducing taurine supplements improves retina function. In cases where medical procedures like chemotherapy and radiotherapy reduce taurine levels in the body, doctors administer taurine supplements to restore retina function. Contact lens manufacturers add taurine in most contact lens solutions. Since all members of the cat family cannot synthesize taurine, the absence of this compound makes cats’ retinas degenerate over time as they age causing blindness. Opticians call this condition Central Retinal Degeneration (CRD).
Taurine is essential in reducing tinnitus and can also help reverse the biological hearing loss. Damages to the ears occur in the nerve cells responsible for converting sound into electrical signals for the brain to interpret. These nerve cells depend on the circulation of calcium to work well. When this circulation of calcium reduces, taurine helps in restoring and maintaining it at optimum levels.
A common cause of seizures is the disruption of normal functioning of excitable brain tissue. Scientific studies on animals reveal that low levels of taurine increases episodes of seizures. Taurine is important in regulating excitable tissues since it works through increasing glutamic acid decarboxylase (GAD) enzyme that produces the neurotransmitter GABA, and binds GABA receptors in the brain consequently calming them and coordinating their movements that fire electric signals. Uncoordinated electric signals increase the likeliness of seizures.
Advanced research reveals that taurine may be the key to treating non-alcoholic fatty liver disease (NAFLD). This disease occurs because of fat accumulation in the liver due to insulin resistance. If the condition remains without rectification, it leads to liver cirrhosis. Taurine helps to protect liver cells by reducing the severity of an oxidative stress-induced liver injury.
Sports and Fitness
Nutritionists and sports experts usually recommend taurine intake to boost athletes’ performance. Physically, the compound makes athletes perform better and longer. Scientifically, taurine increases the contractility of skeletal and cardiac muscles giving them more power. Taurine also removes lactic acid (responsible for pain and soreness) from muscles, enabling them to perform longer and faster. Lastly, the compound protects muscles from oxidant stress.
Members of Passeriformes bird order require taurine to grow and develop. Birds of this order feed their young ones with spiders which have taurine-rich tissues.
Safety and Toxicity of Taurine Supplements
Although one of the most prevalent and important compounds in the human body, there is not enough information about taurine, especially synthetic ones used in food and drink supplements. Due to the controversial nature of health debates on such products, a neutral but thorough explanation is necessary. From the debates, two issues emerge. One, how safe is synthetic taurine? Secondly, up to what amount is the intake of synthetic taurine safe?
Being a conditional amino acid, the body naturally manufactures this compound, unlike essential amino acids. However, some people’s bodies may not manufacture the compound or some may have conditions that require taurine and therefore entirely depend on dietary supplements. Others may just be athletes in need of better performance. Different sources advise an uptake of up to 0.11 ounces of the compound per day for normal and healthy individuals. Amounts of taurine used in energy drinks and food supplements are far below this level and therefore considered safe with no side effects. However, it is important to note that these drinks and supplements may have other chemical compounds that may have independent effects. For example, energy drinks have sugar and caffeine. Too much caffeine may result in an increase in blood pressure and increases the heart rate. This combination works directly against what taurine does, but perhaps the manufactures of such drinks have a formula and measurement for each compound to work as intended. Also, synthetic taurine absorption is more rapid than absorption from natural food and that the liver excretes excess taurine.