Taurine, a lesser known amino acid, is not part of our muscle protein yet is important in metabolism, especially in the brain. It is essential in newborns, as they cannot make it. Adults can produce sulfur-containing taurine from cysteine with the help of pyridoxine, B6. It is possible that if not enough taurine is made in the body, especially if cysteine or B6 is deficient, it might be further required in the diet. In foods, it is high in meats and fish proteins.
Taurine functions in electrically active tissues such as the brain and heart to help stabilize cell membranes. It also has functions in the gallbladder, eyes, and blood vessels and appears to have some antioxidant and detoxifying activity. Taurine aids the movement of potassium, sodium, calcium, and magnesium in and out of cells and thus helps generate nerve impulses. Zinc seems to support this effect of taurine. Taurine is found in the central nervous system, skeletal muscle, and heart; it is very concentrated in the brain and high in the heart tissues.
Taurine is an inhibitory neurotransmitter, and its main use has been to help treat epilepsy and other excitable brain states, where it functions as a mild sedative. Research shows low taurine levels at seizure sites and its anti-convulsant effect comes from its ability to stabilize nerve cell membranes, which prevents the erratic firing of nerve cells. Doses for this effect are 500 mg. three times daily.
The cardiovascular dosage of taurine is higher. In Japan, taurine therapy is used in the treatment of ischemic heart disease with supplements of 5–6 grams daily in three divided doses. Low taurine and magnesium levels were found in patients after heart attacks. Taurine has potential in the treatment of arrhythmias, especially arrhythmias secondary to ischemia. People with congestive heart failure have also responded to a dosage of 2 grams three times daily with improved cardiac and respiratory function. Other possible cardiovascular uses of taurine include hypertension, possibly related to effects in the renin-angiotensin system of the kidneys, and in patients with high cholesterol levels. Taurine helps gallbladder function by forming tauracholate from bile acids; tauracholate helps increase cholesterol elimination in the bile.
Other possible uses for taurine include immune suppression (by sparing L-cysteine), visual problems and eye disease, cirrhosis and liver failure, depression, male infertility due to low sperm motility, and as a supplement for newborns and new mothers. Overall, the dosage used may range from 500 mg. to 5–6 grams, with the higher amounts needed for the cardiovascular problems and possibly epilepsy. Possible symptoms of toxicity from taurine supplementation include diarrhea and peptic ulcers.