taurine and Type I
Introduction
Taurine is a conditionally essential amino acid that
is found in the tissues of most animal species. It is
not incorporated into proteins, but is found free in
many tissues. Taurine is involved in a number of
physiological processes including bile acid
conjugation, osmoregulation, detoxification of
xenobiotics, cell membrane stabilization, modulation
of cellular calcium flux, and modulation of neuronal
excitability. Low levels of taurine have been
associated with retinal degeneration, growth
retardation, and cardiomyopathy. Taurine has been used
clinically in the treatment of cardiovascular
diseases, hypercholesterolemia, seizure disorders,
ocular disorders, diabetes, Alzheimer’s disease,
hepatic disorders, cystic fibrosis, and alcoholism.
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Biochemistry and Biosynthesis
Taurine (2-aminoethanesulfonic acid) is different from
other amino acids in that it contains a sulfonic acid
group in place of the carboxylic acid group, and it is
not incorporated into proteins. Therefore, it is not
an amino acid in the true sense of the word.1 It is
synthesized in human liver tissue from cysteine and
methionine via three known pathways, all of which
require pyridoxal-5′-phosphate, the active coenzyme
form of vitamin B6.2 The highest concentrations of
taurine are found in the neutrophil and the retina,
and the largest pools of taurine are found in skeletal
and cardiac muscles.3 Taurine excretion is via the
urine or in the bile as bile salts.4
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Physiological Functions
Bile Acid Conjugation: Bile acids, primarily cholic
acid and chenodeoxycholic acid, result from
cholesterol metabolism in the liver and are involved
in emulsification and absorption of lipids and
fat-soluble vitamins. In order for this to occur, bile
acids must be bound to either glycine or taurine,
forming bile salt conjugates. The conjugation of bile
acids by taurine results in increased cholesterol
solubility and excretion.5,6
Detoxification: Research has demonstrated that taurine
reacts with and neutralizes hypochlorous acid, which
is generated during oxidative neutrophil burst. The
result is a stable taurochloramine compound, as
opposed to unstable aldehyde compounds formed in
states of taurine deficiency. Individuals who are
taurine deficient may become more susceptible to
tissue damage by xenobiotic agents such as aldehydes,
chlorine, and certain amines.3 Animal studies have
also demonstrated taurine’s ability to complex with
and neutralize the xenobiotic effects of carbon
tetrachloride and retinol.7,8 Research also suggests
that translocation of bacterial endotoxins may be a
factor in determining a person’s response to
xenobiotic insult. Even small amounts of endotoxin
markedly enhance liver injury from hepatotoxic
substances such as carbon tetrachloride, ethanol, and
cadmium. Taurine was found to significantly inhibit
intestinal endotoxin translocation and subsequently
decrease hepatic injury from these substances.9,10
Membrane Stabilization: Taurine’s ability to stabilize
cell membranes may be attributed to several events.
Taurine has been shown to regulate osmotic pressure in
the cell, maintain homeostasis of intracellular ions,
inhibit phosphorylation of membrane proteins, and
prevent lipid peroxidation. As an osmotic regulator,
it has been suggested that taurine, along with
glutamic acid, is instrumental in the transport of
metabolically-generated water from the brain.11
Calcium Flux: Taurine is both an intra- and
extracellular calcium regulator. Excessive
accumulation of intra-cellular calcium ultimately
leads to cell death. Excessive influx of calcium into
cells has been demonstrated in various types of
myocardial injury, as well as migraines and prolonged
epileptic episodes. Taurine supplementation has been
shown to be cardioprotective, and of benefit in
patients predisposed to epilepsy or migraine.4,12
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Clinical Indications
Cardiovascular Disease: Several studies indicate
taurine is a safe, effective therapeutic tool in the
management of various types of cardiovascular disease.
Research indicates supplementation with taurine at
three to six grams daily for two to three weeks
results in reduced serum cholesterol levels in human
subjects when compared to placebo.5,6 In addition,
taurine aids in the regulation of intracellular
calcium levels, thereby protecting heart muscle from
intracellular calcium imbalances, which can lead to
cell death, and subsequent myocardial damage.11
Taurine’s use in preventing cardiac arrhythmia is well
documented and it is thought it may act by modulating
potassium flux in and out of cardiac muscle cells.13
Research has also shown taurine to be capable of
lowering blood pressure, due to its positive inotropic
effects.14,15
Taurine’s antioxidant properties are seen in its
ability to inhibit neutrophil burst and subsequent
oxidative stress, which can result in reperfusion
injury to heart tissue.16 It is also capable of
improving the clinical manifestations of congestive
heart failure. A Japanese study revealed taurine was
significantly more effective than placebo at
decreasing the severity of dyspnea, palpitation,
crackles, and edema in congestive heart failure
patients, while increasing their capacity for
exercise.17
>>>>>Diabetes:<<<<<
Animal and human studies indicate that taurine
supplementation is effective in alleviating some of
the complications of insulin-dependant diabetes.
Taurine has been found to influence blood glucose and
insulin levels, as well as increasing glycogen
synthesis, and it may also be involved in the
functioning and integrity of pancreatic beta cells.3
In insulin-dependent diabetic patients, both plasma
and platelet taurine levels were decreased but were
corrected by oral taurine supplementation.22
I hope some can find this of some use.
All the best
Michael