Taurine

James Meschino DC, MD, ROHP
General Features
Taurine is a non-essential, sulfur–containing amino acid. In the body it can be synthesized from the sulfur-containing amino acids methionine and cysteine. However, some dietary taurine appears to be important to ensure adequate taurine status as retarded growth and degeneration of the retina of the eye have been shown in animals fed a taurine-deficient diet.¹ Very large quantities of taurine are found in the retina of many mammals (including humans), where it helps to protect the photoreceptors in the retina of the eye from ultra-violet light-induced free radical damage. Studies indicate that it may be important as a dietary supplement in cases of optic endemic neuritis and other conditions of the retina.² Besides the retina, taurine is concentrated in other organs that have high electrical activity such as the heart and the brain. Premature infants, patients with cystic fibrosis and some otherwise normal individuals are unable to synthesize sufficient amounts of taurine, making it an essential nutrient in these cases.^1,5 Taurine is only found in foods of animal origin and thus, a vegan vegetarian, with an inborn defect resulting in impaired taurine synthesis, may be at higher risk in developing a taurine deficiency state.^1,5

Clinical Application and Mechanism of Action

1. Congestive Heart Failure

Taurine helps to regulate the contraction and pumping action of the heart muscle. Studies indicate that taurine may support heart muscle function while helping to reverse symptoms of congestive heart failure. In a double-blind, randomized, crossover, placebo-controlled study, taurine supplementation in patients with congestive heart failure was shown to result in significant improvement in the New York Heart Association functional class, pulmonary crackles, and chest film abnormalities as compared to the placebo. Side effects did not occur in the taurine group and the researchers concluded that these results indicate that addition of taurine to conventional therapy is safe and effective for the treatment of patients with congestive heart failure.⁶ In a second study by J Azuma et al, 24 patients with congestive heart failure were given 2 gms of taurine supplementation per day for four to eight weeks. Taurine supplementation resulted in objective signs of improvement in 19 of the 24 patients and, thirteen of fifteen patients who were designated as New York Heart Association functional class III or IV before receiving taurine could be designated as class II after they completed the study, suggesting that taurine was capable of reversing congestive heart disease to a very significant degree in these patients.⁷

2. Insulin-dependent Diabetes Mellitus

There is evidence to show that Insulin-dependent diabetics (IDDM) may have low taurine levels, which may be a factor in their increased susceptibility to excessive platelet clotting leading to cardiovascular disease. In a study by F Franconi et al, 39 IDDM patients and 34 control subjects were recruited for a taurine supplementation study using a dose of 1,500 mg of taurine per day. Initially, the IDDM patients were shown to have significantly lower plasma and platelet levels of taurine than the controls prior to taurine supplementation. After supplementation with taurine the IDDM group realized the same plasma and platelet levels of taurine as the control group and platelet aggregation in this group was reduced, as compared to pre-supplementation measures. This study showed that taurine appears to help reduce the activation of arachidonic acid in the biochemical pathway leading to the formation of pro-inflammatory eicosanoids such as thromboxane A2, which increases platelet aggregation.⁸

3. Cystic Fibrosis

Children with cystic fibrosis frequently have steatorrhea (high levels of fat in their stools due to impaired fat absorption), which has now been linked in part to a deficiency of taurine in their bile acids. Bile acids emulsify fats as part of the fat digestion process. Cystic Fibrosis patients secrete normal levels of pancreatic enzymes and thus, their inability to absorb fat stems from some other defect. Studies have shown that taurine supplementation can effectively reverse steatorrhea in cystic fibrosis patients.^3,4 The study by LJ Smith et al, used a daily dosage of 30 mg/kg body weight per day, in thirteen children with cystic fibrosis. They showed a significant reduction in steatorrhea with a reduction of fecal fatty acid excretion dropping from 26.5g/24 hours to 15.4g/24 hours. Taurine appears to improve the micellar phase of fat digestion as an essential component of the bile complex.⁴

4. Liver Protective Effect (Hepatoprotection) and Detoxification

Animal studies show that taurine supplementation can reduce the toxic effects of cadmium, acetaminophen and carbontetrachloride on the liver and other organs. Under these test conditions, taurine appears to help maintain normal levels of glutathione (in a similar fashion as N-acetyl cysteine, the anti-dote for acute acetaminophen poisoning), which is otherwise greatly depleted by these toxic compounds. Liver cell damage is also minimized to a significant degree and increased fecal elimination of cadmium has been noted with taurine supplementation in these experimental studies.^9,10,11 In general, the dose of taurine commonly used in animal testing is approximately 200 mg/kg of body weight, which is the dose that prevented acetaminophen toxicity in rats injected with 800 mg/kg body weight of acetaminophen intraperitoneally − a level that would otherwise severely damage liver cells. The above noted dose of taurine prevented liver damage in this study and the researchers conclude that taurine supplementation possesses prophylactic and therapeutic effects in acetaminophen-induced hepatic injury.¹⁰ This is an important finding, as chronic use of the pain killer acetaminophen is a frequent cause of severe liver and kidney damage in humans.¹²

Dosage and Standardized Grade

1. Congestive Heart Failure – 1500 to 2000 mg per day in divided doses ⁷
2. Insulin-dependent Diabetes Mellitus – 1500 mg per day in divided doses ⁸
3. Cystic Fibrosis – 30 mg per kg body weight per day, in cases of steatorrhea ⁴
4. Liver Support and Protection – 500 to 5,000 mg per day, depending upon exposures to toxic compounds and degree of previous liver damage ⁵ (see also N-acetyl cysteine in compendium)

Adverse Side Effects, Toxicity and Contraindications
Taurine has been shown to have a depressant effect on the central nervous system and may adversely affect short-term memory. It is the nerve-depressant aspect of taurine that has attracted interest in those who are examining its potential as an agent to treat epilepsy, which involves a state of over excitation. Some preliminary studies indicate that it may have application for epileptics, but further investigation is necessary to establish its efficacy in these cases.^5,13,14,15

Drug-Nutrient Interactions
There are no known instances where taurine supplementation interferes with or potentiates the effects of any drugs, although its biological action in reversing congestive heart failure may be similar to that of cardiac glycoside drugs, such as digitalis and digoxin. Thus, the attending physician should be made aware of the patient’s intent to use taurine supplementation in cases where digitalis is being administered. ^5,6,7

It has been established that various chemotherapy drugs, such as cyclophosphamide, cisplatin, docetaxel, fluorouracil, methotrexate and paclitaxel, deplete body stores of taurine and, thus, supplementation with taurine may be advisable when taking these drugs. ¹⁶

1. Hendler S. The Doctor’s Vitamin and Mineral Encyclopedia. Simon and Schuster 1990;224-5
2. Gonzalez-Qevedo A, Obregon F, Santiesteban Freixas R, et al. Amino acids as biochemical markers in epidemic and endemic optic neuropathies. Rev Cubana med Trop 1998;50(Suppl):241-4
3. Thompson GN. Excessive fecal taurine loss predisposes to taurine deficiencyin cystic fibrosis. J Pediatr Gastroenterol Nutr Mar1988;7(2):214-9
4. Smith LJ, Lacaille F, Lepage G, et al. Taurine decreses fecal faty acid and sterol excretion in cystic fibrosis. A randomized double-blind trial. Am j Dis Child Dec1991;145(12):1401-4
5. Dietary Suplement Information Bureau, USA: Taurine (Dietary Supplementation Education Alliance, copyright 2001)
6. Azuma J, et al. Therapeutic Effect of taurine in congestive heart failure: a double-blind crossover trial. Clin Cardiol May 1985;8(5):276-82
7. Azuma J, et al. Therapy of congestive heart failure with orally administered taurine. Clin Ther 1983;5(4):398-408
8. Franconi F et al. Plasma and platelet taurine are reduced in subjects iwith insulin-dependent diabetes mellitus: effects of taurine supplementation. Am J Clin Nutr May1995;61(5):1115-9
9. Hwang DF, Wang LC. Effect of taurine on toxicity of cadmium in rats. Toxicology Oct2001;167(3):173-80
10. Waters E, Wang JH, Redmond HP, et al. Role of taurine in preventing acetaminophen-induced hepatic injury in the rat. Am J Physiol Gastrointest Liver Physiol Jun2001;280(6):G1274-9
11. Wu C, Kennedy DO, Yano Y, et al. Thiols and polyamines in the cytoprotective effect of taurine on carbon tetrachloride-induced heptotoxicity. J Biochem Mol Toxicol 1999;13(2):71-6
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13. Barbeau A. Zinc, taurine and epilepsy. Archives of Neurology 1974:30-52
14. Barbeau A, et al. The neuropharmacology of taurine. Life Sciences 1975;17:669-78
15. Takahashi R, Nakane Y. Clinical trial of taurine in epilepsy. In:Barbeau A and Huxtable RJ (eds.), Taurine and Neurological Disorders, New York. Raven Press 1978:p375
16. Desai TK, Maliakkal J, Kinzie JL, et al. Taurine deficiency after intensive chemotherapy and/or radiation. Am J Clin Nutr 1992;55:708-11